Document text
HE
203
. A56
r>o.
83-21
Department of
ransportation
)ffice of the Secretary
)f Transportation
July 1981
Field Manual on Design and
Construction of Seal Coats
DEPARTMENT OF
transportation
OCT 1983
Prepared for
Texas State Department
of Highways and
Public Transportation
department of
TRANSPORTATfON
OCT 19S3
*y,
UBRARY
FIELD MANUAL
on
DESIGN AND CONSTRUCTION OF SEAL COATS
by
J. A. Epps, B. M. Gallaway, and C. H. Hughes
Research Report 214-25
July 1981
TEXAS TRANSPORTATION INSTITUTE
The Texas A^M University System
College Station, Texas
DEPARTMENT OF
TRANSPORTATION
OCT 1983
UBRARY
STATE DEPARTMENT OF HIGHWAYS AND PUBLIC TRANSPORTATION
TASK FORCE ON ENGINEERING, ECONOMY AND ENERGY CONSIDERATIONS
Larry G. Walker, Task Force Chairman and Materials and Tests Engineer
Charles H. Hughes, Sr., Study Contact Representative and Assistant
Materials and Tests Engineer
A.H. Pearson, Jr., Assistant State Engineer-Director
Wayne Henneberger, Bridge Engineer
Robert L. Lewis, Chief Engineer, Highway Design
Byron C. Blaschke, Chief Engineer, Maintenance Operations
J.R. Stone, District Engineer
William V. Ward, Urban Project Engineer-Manager
Phillip L. Wilson, State Planning Engineer
Franklin C. Young, District Engineer
Theodore E. Ziller, Construction Engineer
The contents of this report reflect evaluations of seal coats
using a Texas Grade 4 Aggregate. Texas grade 4 aggregate
meets the following specification requirements:
% by weight
Retained
on
5/8"
seive
II
II
1/2"
II
II
II
3/8"
II
II
II
No. 4
II
II
II
No. 10
it
0
0-2
20-35
95-100
99-100
Care should be exercised when designing a seal coat by the procedure
in this manual if the aggregate varies significantly.
1
Table of Contents
Page
I. INTRODUCTION 1
II. PURPOSE AND USES OF SEAL COATS 2
III. DESIGN OF SEAL COATS 3
A. Type of Aggregate 4
B. Type of Asphalt 7
C. Design Method 9
1. Laboratory Tests 10
2. Calculations 10
3. Sample Calculations 11
4. Environmental Considerations 15
5. Aggregate Embedment 17
IV. CONSTRUCTION 17
A. Equipment 18
B. Construction Operations 19
C. Inspection and Quality Control 29
V. SUMMARY 32
INTRODUCTION
■*
Seal coats have been successfully used on Texas highways for many
years and with traffic volumes as high as 4000 vehicles per lane per day.
The average life of seal coats is about six to seven years in Texas,
however; some seal coats have performed successfully for periods of 20
or more years. These economical surfaces will continue to be a popular
rehabilitation and maintenance alternative in Texas and their use in
other states will increase as available highway funds decrease.
The purpose of this manual is to provide guidelines for the design
and construction of seal coats. If followed, these guidelines will
improve the chance of successfully placing seal coats. The manual is
directed primarily to office and field engineers, laboratory personnel,
and field inspectors responsible for the design and construction of
seal coats. An extensive discussion of the variables affecting the design
and construction of seal coats is not presented in this manual. References
1 to 15 contain a detailed discussion.
*A seal coat is a bituminous surface that results from one or more
successive alternative applications of bituminous binder and cover
aggregate to an existing paved surface. A surface treatment is a
bituminous surface that results from one or more successive alternative
applications of bituminous binder and cover stone to a prepared compacted
gravel, crushed stone, stabilized soil or similar base.
1
PURPOSE AND USES OF SEAL COATS
Seal coats are applied to an existing bituminous surface for
one or more of the following purposes:
1. Seal an existing bituminous surface against the entrance of
air and water
2. Enrich an existing dry or raveled surface
3. Provide a skid resistant surface
4. Increase pavement visibility at night
5. Reduce tire noise
6. Improve demarcation of traffic lanes or other geometric features
7. Attain a uniform appearing surface
Little increase in load carrying capacity is obtained from the additional
pavement thickness supplied by the seal coat; however, an effective seal
may improve the load carrying ability of a pavement by altering the
water content of the materials composing the pavement structure. If a
pavement surface shows evidence of traffic load associated cracking
(alligator, longitudinal, transverse), a seal coat is only a temporary
solution. A thick asphalt concrete overlay or reconstruction is
normally required to correct these types of problems.
Rough riding pavement surfaces cannot be improved significantly by
the application of a seal coat. Overlays of various thickness, spot
level-up maintenance patches, or reconstruction is normally required to
restore pavement ride quality.
Seal coats applied to pavements showing signs of non-traffic load
associated longitudinal and transverse cracks have proved somewhat
2
effective. Seal coats usually bridge these cracks in a more satis-
factory manner than thin asphalt concrete overlays. Other pavement
overlay systems, some of which contain seal coats with special binders
are being developed and appear promising.
Pavements demonstrating flushing or bleeding are difficult to
repair with seal coats. The bleeding normally migrates through
the new seal coat unless the asphalt quantity applied to the roadway
can be altered at these spot locations. Asphalt concrete overlays
have proven to be more effective in reducing or eliminating flushed
surfaces. Seal coats utilizing a large maximum size aggregate are
suggested, if seals are utilized on flushed surfaces.
Pavements with ruts or corrugations normally must be repaired with
an overlay, heater planer or cold planers. Seal coats are not an
effective treatment for these types of distress.
Seal coats have been used successfully on pavements carrying 5,000
vehicles per day per lane in rural areas. The probability of successfully
placing a seal coat is,. however, greatly increased on roadways carrying
lower traffic volumes. The use of seal coats in urban areas where
accelerating and decelerating traffic frequently occurs should be
approached with caution.
DESIGN OF SEAL COATS
The design of seal coats involves the selection of the type and
amount of bitumen or asphalt and the type and amount of aggregate.
Selection of the type of aggregate and asphalt will be discussed
3
followed by the description of a method to determine the amount of
asphalt and aggregate.
Type of Aggregate
The mineral aggregate in a seal coat is expected to:
1. Transmit the vehicle wheel load to the underlying surface.
2. Provide a skid resistant surface.
3. Resist abrasion from moving wheel loads.
4. Resist the deteriorating effects of weather exposure.
In addition, cover aggregates sometimes are used to improve light
reflection from the roadway and/or to provide a demarkation of shoulders
or other limited traffic areas.
Aggregates for seal coats are adequately specified under the follow-
ing Texas State Department of Highways and Public Transportation
specification items (16).
Item 301 - Aggregate for Surface Treatments (Class A)
Item 302 - Aggregate for Surface Treatments (Class B)
Item 303 - Aggregate for Surface Treatments (Lightweight)
Item 304 - Aggregate for Surface Treatments (Precoated) (Class B)
Item 305 - Aggregate for Surface Treatments (Precoated) (Class A)
Precoated aggregates are more expensive than untreated aggregates
but have been utilized to reduce the effect of a dusty aggregate, to
reduce automobile glass damage due to flying stone and to promote bond
with the asphalt. Lightweight aggregates have been utilized since 1961
in Texas to provide pavements with a high coefficient of friction, color
contrast and to reduce or eliminate glass damage due to flying stone. Selection
4
of the specification item for designation of cover stone has been based
largely on availability and cost of materials, materials performance
and skid resistance considerations. A preferred natural aggregate is
that specified under Item 301 with a one size gradation. The one
size gradations allow additional asphalt to be used effecting a more
positive seal and reducing the likelihood of aggregate loss and the
associated resulting automobile glass damage and bleeding surfaces. If
there is too much difference between the largest and smallest size
particles, the asphalt film may completely cover the smaller sizes but
will not adequately grip the larger sizes. In addition, a "one size"
aggregate will produce superior particle interlocking and will result in
an optimum contact area between the tire and road surface. For
practical purposes, a cover aggregate having 85 weight percent
passing a specified size sieve and retained on a sieve having a open-
ing one-half the specified size can be considered to be "one-size".
The ideal cover aggregate particle shape is cubical or pyramidal,
but rounded gravels have provided satisfactory service on low traffic
volume roads. Crushed gravels provide improved performance as
compared to subrounded or rounded gravels. Lightweight aggregates
often are not cubical or pyramidal, but they tend to have the rough
surface features desired for a good cover aggregate. Flat and
enlongnated particles should be avoided. The presence of such particles
can be minimized by specifying a maximum percentage of particles
having a ratio of width (smallest dimension) to average particles
size less than 0.5 (flakiness index Tex-224-F).
The selection of the maximum size of aggregate is normally based on
5
economic and traffic considerations. Large maximum size cover stones require
larger amounts of asphalt than small maximum size cover stones. For example,
a Grade 5 cover stone with a maximum size of one-quarter inch requires
approximately 0.20 gallons of asphalt per square yard while a Grade 3
cover stone with a maximum size of five-eights inch requires approximately
0.40 gallons of asphalt per square yard. It is evident that Grade 3
cover stone will provide a more effective seal because of the thickness
of the applied asphalt film. Field variations in applied asphalt
quantities which are of the order of 0.06 gallons per square yard are
much more critical for Grade 5 than for Grade 3 cover stone.
It is a common practice in the state to select the larger maximum
size aggregates for the high traffic volume facilities. Grade 3 or 4
is normally utilized on these facilities. In addition, the larger
maximum size cover stone improves pavement surface drainage and thus
reduces the potential for hydroplaning. Tire-pavement noise is usually
higher with Grade 3 aggregates.
As mentioned above, skid resistance is an important if not the
controlling factor, in the selection of the type of aggregate to be used as a
surface treatment or seal coat cover stone. It is important that the
aggregate have an adequate initial coefficient of friction, and that
a prolonged coefficient is maintained under the traffic imposed on
the facility. Polish values, as determined by Test Method Tex-438-A,
may be utilized to select acceptable aggregates for individual projects.
Potential benefits and problem areas associated with the selection
of lightweight and normal weight aggregates are shown in Table 1.
Table 2 recommends types and grades of aggregates for seal coats.
6
These should be considered as guidelines rather than firm recomnendations .
Modifications should be made (as necessary) to fit specific local conditions.
Type of Asphalt
The type and grade of asphalt selected for a particular seal coat
project should have the following characteristics:
1. Fluid enough at the temperature of spraying to allow uniform
appl ication,
2. Fluid enough at the time the cover aggregate is applied to
develop rapid wetting and fast initial adhesion between the binder and
the aggregates as well as to the underlying road surface.
3. Viscous or hard enough to retain the cover stone when the surface
is opened to traffic.
4. Viscous or hard enough to prevent plastic distortion in
hot weather.
5. Fluid or soft enough (not brittle) in cold weather that the
aggregate will not be whipped off and the road surface will not crack.
6. Resistant to the effects of sunlight and air (prevent excessive
hardening due to aging of the asphalt)
7. Resistant to the combined action of water and traffic such
that stripping of the aggregate will not occur.
Asphalt cements, emulsified asphalts and cut-back asphalts, as
specified by Item 300 of the Texas State Department of Highways and Public
Transportation Standard Specification, are utilized for seal coats. Each
of the three types of asphalt products has its own virtues and problems
which should be recognized when a selection is made.
7
Table 3 lists advantages and potential problems associated with
these asphalt types.
Many grades of the three types of asphalt are available, but only
a few are normally used for seal- coats. These are shown below.
Asphalt Type
Asphal t Cement
Asphalt Emulsion (Anionic)
Asphalt Emulsion (Cationic)
Cut-Back Asphalt*
Identification Under Item 300.2
SDHPT Standard Specifications
Viscosity Grades AC-5, AC-10
EA-HVRS, EA-HVRS-90 (EA-HFRS)
ER-CRS-2, EA-CRS-2h
RC-2, RC-250, RC-3, RC-4, RC-5, MC-800, MC-3000
Recommendations for selection of asphalt type and grade based on
criteria for the construction environment and expected surface exposure
conditions in various parts of the state are given in Tables 4 and 5
and supported by Figure 1. These should be considered to be guidelines
rather than firm recommendations. Modifications should be made (as necessary),
to fit specific local conditions.
Selection of the proper type and grade of asphalt also depends on
the type of cover aggregate to be spread on the asphalt layer. Guidance
for making a selection on the basis of aggregate type is given in Table 6
and Figure 2. Application of Figure 2 for classification of natural
gravels may pose some problems since aggregates often consist of a
mixture of a number of rock types. However, aggregates
may be classified from a knowledge of the local geology, and petrographic
and/or visual examination. For example, most natural gravel taken
*Energy conservation and air quality problems will usually rule out
the use of cut-back asphalts except for emergency repair during the
winter months.
8
from the Brazos River terraces have a relatively high silica content
and are therefore mostly hydrophilic. When there is doubt, personnel
of the Texas State Department of Highways and Public Transportation
Materials and Test Division (D-9) should be consulted.
The final selection of the type and grade of asphalt to be used
should be made on the basis of recommendations presented on Tables
4, 5, 6, and Figure 2 (17). For example, if a chip seal is to be
applied during the summer in a Zone lA climate and trap-rock aggregate
is used the following types of asphalts would be expected to give
satisfactory performance; AC-5, AC-10, EA-CRS-2, and EA-CRS-2h. If
a chip seal is to be applied in the spring in a Zone I IB climate and
a lightweight aggregate is used, the best choice is the cationic
asphalt emulsion EA-CRS-2. An RC-4 or RC-5 could be used.
Selecting asphalts for late season construction presents special
problems as the cover stone is normally not embeded to the desired level
prior to the occurrence of cold nights. With shallow embedment depths
and a somewhat brittle asphalt; raveling at the centerline, between the
wheel paths and perhaps in the wheel path will likely occur. If construc-
tion must occur late in the summer or early in the fall, the grade of
asphalt cement to be selected should be one grade softer than normally
used (i.e., AC-5 rather than AC-10 and AC-3 rather than AC-5).
Design Method
The design method recommended and described below is based on a
modification of the original Kearby method which has been utilized by
several districts (7, 9, 14). Laboratory tests and calculations required
in the design method are given below.
9
Laboratory Tests
Dry Loose Unit Weight. The dry loose unit weight determination
shall be made in accordance with Tex-404-A, except that the aggregate
shall be tested in an oven-dry condition.
Bulk Specific Gravity. The bulk specific gravity shall be made in
accordance with Tex-403-A for all natural aggregate and by the test method
Tex 433-A for synthetic aggregates.
Board Test. Place a sufficient quantity of aggregate on a board
of known area such that full coverage one stone in depth is obtained.
A one-half square yard area is a convenient laboratory size. The weight
of the aggregates applied in this area is obtained and converted to
units of pounds per square yard. Good lighting is recommended and
care should be taken to place the aggregate only one stone deep.
Calculations
The quantity of aggregate expressed in terms of square yards of
road surface that can be covered with a cubic yard of aggregate and the
quantity of asphalt in gallons per square yard can be found as described
below:
Aggregate Quantity
c _ 27W
^ ■ Q
A = 5.61E (1 - (T) + V
where:
S = Quantity of aggregate required, sq. yds. per cu. yd.
W = Dry loose unit weight, lbs. per cu. ft.
10
Q = Aggregate quantity determined from board test, lbs. per sq. yd.
A = Asphalt quantity, gallons/sq. yd. @ 60°F
E = Embedment depth obtained from Figure 3 as follows:
E = ed
where:
e = Percent embedment (Figure 3)
d = Average mat depth, inches
= 1.33Q
W
G = Dry bulk specific gravity of aggregate
T = Traffic correction factor obtained from Table 7
V = Correction of surface condition obtained from Table 8
5.61 = (7.48) (9/12), or conversion factor
Note: Asphalt quantities calculated by these methods are for
asphalt cement. Appropriate corrections must be made
where a cutback or an emulsion is used as illustrated
in the examples given below.
Sample Calculations
Given:
(W) Dry loose unit weight of aggregate = 52.4 Ibs/cu.ft.
(G) Dry bulk specific gravity of aggregate =1.57
(Q) Quantity of aggregate (board test) =9.7 Ibs./sq.yd.
Traffic = 700 vehicles per day per lane
Roadway Surface Condition + slightly pocked, porous, oxidized
11
Quantity of Aggregate
27W _ 27(52.4)
Q 97
= 146 sq. yds. (square yards of roadway surface
per 1 cubic yard of aggregate)
Quantity of Asphalt
A = 5.61E (1 -
W
62. 4G
) (T) + V
j 1.33Q 1.33(9.7) ^
d 52.4
e = 40 percent from Figure 3 for synthetic aggregates
E = ed = .40(.246) = 0.0985 inches
T = 1.05 from Table 7
V = +0.03 from Table 8
A = 5.61 (0.0985) (1 - 62.40'^57)^
A = 0.30 gallons of asphalt per square yard of roadway surface
If an emulsion or cutback is to be used, the quantity to be
utilized must be corrected for the amount of volatiles present in
the asphalt material. The approximate amount of volatiles present in
those cutbacks recommended for use in seal coats is shown on Table 9-
For example, the seal coat design method suggests that 0.30 gallons
per square yard of residual asphalt cement is required. Theoretically
the amount of RC-250 to be placed on the pavement is
= 0.40 gallons per square yard
However, field experience indicates that bleeding is likely if the
theoretical amount is utilized. Thus, it is recommended that the
calculated theoretical value be reduced and the method described below
be utilized to calculate the amount of cutback to be utilized.
12
A =A+KfA -A^
^recommended '^theoretical '
where:
/\
recommended
= recommended quantity of cutback or emulsified
asphal t
A
= residual quantity of asphalt obtained from the
design method given above
A
theoretical
= theoretical quantity of cutback or emulsified
asphalt obtained by dividing A by the quantity
of residual asphalt in the cutback (Table 9) or
emulsion and as described above.
K
= correction factor based on field experience
It should be noted that correction factors (K) have not been
verified for cutbacks by carefully controlled field experiments and
therefore should be used as guidelines only: Suggested K factors
for cutbacks are as follows:
K = 0.70 for spring construction
K = 0.60 for summer construction
K = 0.80 for fall construction
K = 0.90 for winter construction
If the RC-250 is to be placed in the fall, the quantity to be used is
A
recommended
= 0.30 + 0.80 - 0.30)
/\
recommended
= 0.38 gallons of RC-250 per square yard of roadway surface
Field trial sections placed in Texas and reported in reference 18
suggest that reduced quantities of emulsion (as compared to the theoretical
value calculated) can be utilized successfully. Thus, it is recommended
13
that the calculated theoretical value be reduced and the method out-
lined above be utilized.
It should be noted that corrective factors (K) have not been verified
by extensive controlled field' experiments and therefore should be
used as guidelines only. Suggested K factors for emulsions are as
follows:
K = 0.60 for spring construction
K = 0.40 for surmier construction
K = 0.70 for fall construction
K = 0.90 for winter construction
Assuming that the design method suggests that 0.30 gallons per
square yard is required, the amount of an EA-CRS-2h emulsion that
contains 70 percent residual asphalt that should be used in the summer
is
''reco^ended = " ^AO - 0.30)
''recommended = gallons of EA-CRS-2H emulsion
per square yard of roadway surface.
It should be noted that the quantity of asphalt to be sprayed
from the asphalt distributor must be corrected for temperature in order
that the proper quantity will be retained on the roadway as measured at
60°F. If the design quantity of asphalt cement was 0.30 and the spray
temperature was 340°F, the temperature correction factor would be
0.9057 (Table 10). Thus, or 0.33 gallons of asphalt cement per
square yard would be sprayed at 340°F in order to have 0.30 gallons per
square yard on a 60°F surface. Temperature correction factors for
asphalt cement are shown in Table 10, for cutbacks in Table 11 and for
emulsions in Table 12.
14
Environmental Considerations
Experience shows that the ideal environment for the construction of
seal coats is hot, dry weather with no rain for the next several days.
Thus, the two most important environmental factors are temperature and
moisture. Wind velocity is also a factor to be considered.
Both road surface and atmospheric tempev’atures are important because
they will influence how well the cover aggregate can be embeded in the
binder and then how soon the roadway can be reopened to traffic. Soon
after the asphalt is shot, its temperature will approach that of the
roadway surface temperature. At this temperature the asphalt will be
much more viscous (thicker) than at the spraying temperature. If the
road surface is cool, the binder may become so viscous (depending on
the type and grade of asphalt) that it will become nearly impossible
to obtain adequate adhesion between the aggregate and asphalt and
proper aggregate embedment during the rolling operation. The net
result will be aggregate loss when the roadway is opened to traffic.
Aggregate loss may also cause windshield damage and even result in loss of
friction. On the other hand, if the road surface temperature is too
high and the asphalt is low in viscosity a longer time will be required
to cool the mat to the point where traffic will no longer dislodge the
aggregate particles. During hot, sunny weather, the most critical
time of day to reopen a new seal coat job to traffic is between midday
and late afternoon when the pavement surface temperature is highest. This
problem will be most serious when dark colored aggregates are used
and the area is one of high solar flux.
Asphalt emulsions have relatively low viscosities at low temper-
ature as compared to asphalt cement. This physical feature of
15
emulsions allows this asphalt material to satisfactorily adhere to
the aggregate and to obtain adequate embedment at lower road surface
temperatures.
Wet aggregates will not adhere to asphalt cements. However, wet
aggregates can, be used with asphalt cements provided the water evaporates
from the aggregate surface and adequate adhesion is obtained prior to
finish rolling and opening to traffic. If wet aggregates and asphalt
cements are to be used successfully, they should be used on hot, low
humidity days. Wind will speed aggregate drying and thus promote adhesion.
Similar reasons dictate that asphalt cement should not be sprayed
on top of a wet pavement surface.
The problems with moisture are reduced considerably if cationic
asphalt emulsions are used. If properly compounded and used, such
emulsions tend to displace surface water and allow the binder to make
direct contact with the aggregate surface. However, an excess of
moisture may slow the emulsion break and the evaporation of the
separated water which may still present problems.
Wind speed is also a consideration. A light breeze may help
evaporate moisture (or the solvent from cutbacks). High
winds may distort the distributor spray pattern making it impossible to
obtain uniform asphalt coverage. Also, in some areas the dust carried
by high winds will have detrimental effects.
Specific limits for the environmental conditions prevailing
during construction are given in Table 5. If these limits are carefully
observed the chance of successfully placing a seal coat is greatly
improved.
16
Aggregate Embedment
The seal coat design method, the construction operations and
considerations for climatic conditions should be aimed at providing
adhesion between the asphalt binder and the aggregate and proper
embedment of the aggregate into the asphalt film. Improper adhesion
and/or inadequate embedment depth will result in loss of coverstone
aggregate. Suggested percent embedment depths during the life of seal
coats are listed below:
immediately after construction 30 + 10%
start of cool weather (first year) 35 + 10%
start of cold weather (first year) 45+10%
after two years of service 70+10%
For low traffic facilities aggregate embedment immediately after construction
should be in the range of 30 to 40 percent while 20 to 30 percent embedment
is the preferred range for high traffic volume facilities.
CONSTRUCTION
The performance of seal coats is largely dependent upon the quality
of construction. Design quantities of asphalt and aggregate must be
placed uniformly on the roadway using a sequence of operations which
results in proper adhesion between the aggregate and the asphalt
binder. Quality construction requires a coordinated effort among the
construction labor force, the construction equipment, traffic control
personnel and field inspection personnel. Key items associated with
proper construction of seal coats are discussed below.
17
Equi pment
Successful construction of high quality, long service life seal
coats depends to a large degree on the equipment selected for the job,
its operating condition and the way it is handled during construction.
The following form basic types of equipment that are required,
1. Asphalt distributors,
2. Aggregate spreaders,
3. Rollers and
4. Cleaning Equipment
The asphalt distributor must be able to spray the asphalt binder
uniformly across and along the road surface at a rate to give the
coverage indicated by the design calculations. The operator should
be able to maintain close control of the asphalt application rate
regardless of changes in grade. The major features of an asphalt
distributor are shown in Figure 4,
The function of an aggregate spreader is to apply the cover aggregate
uniformly on top of the asphalt shot at the specified spread rate. A
good spreader, properly operated, will conserve aggregate as well as
help to obtain a high quality seal coat. A good spreader should be
able to:
1. Keep up with the asphalt distributor,
2. Cover the asphalt shot with a minimum of stopping to reload and
3. Synchronize the aggregate discharge rate with the forward
speed to minimize the effect of small changes in grade, etc.
in the spread rate.
Self-propelled spreaders such as the ones illustrated in Figure 5 will
18
usually meet these requirements.
The purpose of the rolling operation is to press the cover aggregate
particles firmly into the asphalt layer so as to improve embedment, and
to promote adhesion and particle interlock, A self-propelled pneumatic-
tired roller, as illustrated by Figure 6, is preferred. These pneumatic
rollers tend to minimize the tendency for weak aggregate particles to
degrade during the rolling operation. The use of steel wheel rollers
should be avoided.
Suitable equipment is required to clean the existing surface and
to remove excess aggregate after the asphalt hardens on the road. Power
brooms such as that shown on Figure 7 are typically utilized for
these operations.
A large number of manufacturers produce the four types of equipment
required to construct seal coats. Many models will do an excellent job,
but among the various manufacturers, design details will differ considerably.
Construction Operations
The sequence and timing of construction operations are critical
if a properly performing seal coat is to be constructed. The key
operations and the sequence of these operations are given below.
1 .
Preconstruction preparation.
4.
Aggregate spreading.
p.
Traffic control.
5,
Rolling and
3.
Asphalt application.
6.
Final clean-up
Timing of the construction sequence is critical. For example,
patching of the old surface prior to placing the seal coat should be
completed several months (if possible) before a seal coat is applied.
The time available between patching and placing of the seal coat will
19
allow volatiles to escape from the patching materials and thereby reduce
bleed-through. Patch densification by traffic is also beneficial.
The time delay between asphalt application and aggregate spreading
very critical when asphalt cements are utilized. The delay should be
minimized and is especially critical for early morning construction and/or
early and late season construction when the surface temperature of the old
pavement is low.
The time delay between emulsion or cutback application and aggregate
spreading is not as critical as that associated with the use of asphalt
cements. In general, aggregate should be applied to the emulsion or cutback
shot as soon as possible (provided the aggregate is not picked up by the wheels
of the aggregate spreader). It is not necessary for the emulsion to break or
the cutback to cure before the aggregate is applied.
Rolling should be initiated immediately after aggregate spreading, pro-
vided aggregate pick up is not a problem. The time delay between aggregate
spreading and rolling is critical and should be held to a minimum when asphalt
cements are used. The time delay between aggregate application and rolling
is not as critical for emulsions and cutback as compared to asphalt cements.
However, this time delay should also be minimized provided rolling can be
accomplished without aggregate pick up.
Aggregate pick up by the aggregate spreader or rollers is not necessarily
due to spreading the rock or rolling too soon after placing the asphalt. In-
the asphalt. Incorrect selection of the asphalt, improper delivery of
excess asphalt application rate, insufficient aggregate spread rate and asphalt
on roller tires are some of many reasons why pick up could also occur.
20
Final clean-up which usually consists of brooming of excess and/or
loose aggregate from the pavement and shoulders should be attempted only
after the aggregate is firmly set in the asphalt. This time delay is
usually 15 to 24 hours after construction but may be longer during hot
weather and/or when emulsions or cutbacks are used. Final brooming is
normally performed during the cooler morning temperatures.
Several key steps should be taken in each of the identified seal
coat construction operations. The exact sequence of steps and the degree
of execution of each of those steps will depend, in part, on the local
conditions such as highway geometries, special aggregate considerations,
environmental conditions, personnel available, equipment available, etc.
Rather than attempt to present specific directions for conducting each of
the construction operations a series of summary tables has been prepared to
identify key steps of each operation. This information is summarized below
and should be supplemented by Chapter 8 of the SDHPT construction Manual (19).
Preconstruction Preparation. Careful planning and preparation for
a seal coat j,ob will yield many benefits. After the materials have been
selected and produced, the design calculation made, contractural arrangements
completed, and the construction schedule determined, the following actions
are particularly important and may very well determine the success of the project.
Preparation of Existing Asphalt Pavement. Often the condition of the
old pavement upon which the seal coat is to be placed is in need of repair
prior to application of the seal coat. Suggested actions are shown on
Table 13 for various types of pavement distress. If the pavement
has excessive bleeding, rutting, or alligator cracking, a seal
21
coat may not be an acceptable rehabilitation alternative.
Aggregate. Sufficient quantities of aggregate should be stockpiled
along the road to complete the project. Stockpiles should be spaced for
most efficient operation of the aggregate trucks and spreader. Stock-
pile areas should be well drained to minimize the flow of water through
and under the aggregate, and should be free of grass, rubbish and other
contaminants. In areas of high rainfall, the engineer should consider
covering stockpiles to insure that they remain dry.
Each aggregate stockpile should be sampled and tested well before
construction begins. Stockpiled aggregate should give uniform test results
consistent with the values used in design calculations. All specification
requirements should be met.
Asphal t . Adequate asphalt storage facilities should be provided
in convenient locations. Adequacy is determined by facility type
(capable of handling the type and grade of asphalt specified), size,
and condition (clean, leak free, operation without excessive maintenance
and repair). Each lot of asphalt should be sampled and tested for
specification compliance. Uniform test results consistent with values
used in design should be required. Special sampling and handling
may be required for asphalt emulsions in view of their tendency to
separate.
Equi pment. The contractor should be required to permanently
assign equipment to the project, in adequate numbers of each kind, for
the duration of the project. This action will reduce delays and avoid
having to proceed on a makeshift basis which is almost certain to
result in poor performance. The responsible engineer should insist on
22
compliance with the operational requirements specified for each item of
equipment. All adjusting mechanisms should be fully operational.
Distributor tank and other calibrations required should be on hand; not
merely promised at a future date.
Traffic Control. Traffic must be controlled to protect the
driving public and their vehicles, the construction crew and construction
equipment and to avoid damage to the seal coat during construction
and when the job is first opened to traffic. The preferred method
is to detour traffic completely until the binder is hard enough to hold
the aggregate tightly. When this is not possible, half width construc-
tion should be used and traffic confined to lanes not under construction.
If traffic must be maintained during construction, vehicle speed must
be limited to 5 to 10 mph using a pilot vehicle. After rolling is
complete, traffic speed on the newly placed surface should be limited
to 20 mph for the following time periods;
1. Asphalt cement, hot weather - 2 hours
2. Asphalt cement, cool weather - 1 hour
3. Emulsion and cutbacks - 2 hours (extend to 3 or more hours in calm,
humid weather)
Longer time delays may be required if the seal coat is placed on a high
traffic volume facility and/or if the facility has a high volume of trucks.
Asphalt Application. The asphalt must be applied to the old
roadway surface in a uniform manner and at an amount equal to the
design quantity. Modern equipment is capable of applying a uniform
23
coverage of asphalt of the correct quantity provided the equipment
is maintained in proper operating condition and the asphalt is
sprayed at the proper viscosity. The spray bar height and nozzle
angles must be properly adjusted if the desired uniformity is to be
achieved (Table 14, Figure 8).
Distributor Calibration. All distributors should be calibrated.
Two types of calibrations should be performed. The asphalt tank on
the distributor should be calibrated such that an accurate relationship
between fluid level and asphalt binder quantity is obtained. The
second calibration involves the determination of the variation in
transverse and longitudinal distribution or spread of the asphalt
along the roadway. Transverse spread should not be allowed to vary
more than 15 percent for asphalt emulsions and no more than 10 percent
for other types of asphalt binders. Longitudinal spread should
not vary more than 10 percent regardless of the type of binder.
Methods for determining transverse and longitudinal spread have
been developed by the Texas State Department of Highways and Public
Transportation (22), the Asphalt Institute (2), and the California
Division of Highways (20). Appendix A contains a description of the
California test method.
Spray Nozzles. Recent research conducted by Distric 23 of the
Texas State Department of Highways and Public Transportation has i-ndi-
cated that spray nozzles of identical manufacture identified size
deliver liquid quantities at widely different rates and fan widths.
If transverse distribution cannot be controlled within desired limits
it may be necessary to replace individual nozzles.
24
Under certain conditions it may be desirable to vary the
transverse distribution of asphalt. For example, the wheel paths may
be bleeding with little or no surface texture while the areas of the
roadway between the wheel path and outside the wheel path may appear
dry with considerable surface textures. Since the surface demand for
asphalt varies transversely on the pavement, it is desirable to vary
the applied rate transversely. District 23 has successfully installed
different size nozzles in the spray bar to achieve the desired
transverse variation. Additional information may be obtained by
contacting the district office in Brownwood.
Spray Temperature. The temperature at which the asphalt binder
is to be discharged or sprayed from the distributor is based on the
viscosity of the binder. The recommended viscosity range for spraying is
20 to 120 centi stokes or centipoises. A temperature-viscosity chart is the
best method for selecting the temperature that defines the viscosity
for spraying. Figures 9 and 10 are typical graphs for asphalt materials
used for seal coats in Texas. The temperature-viscosity relationship
for the asphalt to be used on the project should be obtained from the
Materials and Tests Division in Austin and plotted as shown in Figure 11.
Typical temperatures for spraying seal coat binders are shown on Table 15.
Distributor Speed. Distributor speed for any rate of application
can be determined from the following formula.
WR
where:
= road speed, feet per minute
25
= spray bar output, gallons per minute
W = sprayed width, feet and
R = rate of binder application, gallons per square yard
The rate of binder application is obtained from the design calculations and
corrected for temperature. For example, the design quantity of AC-10 to be
used on a project is 0.30 gallons per square yard. Temperature-viscosity data
have been obtained for the asphalt cement and plotted on Figure 11. An asphilt
temperature of 340°F is selected (viscosity of 33 centipoises, i.e., between 20
and 120 centistokes as suggested by the Asphalt Institute and discussed previously).
The rate of binder application at 340°F is equal to
6'*W5~7 ~ gallons per square yard
This rate of application will provide 0.30 gallons per square yard on the
pavement surface at 60°F.
The spray bar output can be obtained from the distributor manufacturers
manual of operation. The discharge quantity is a function of the pump RPM,
pump pressure, binder viscosity, spray bar width, etc. The discharge
quantity should be converted to gallons per minute for the spray bar width
to be used on the job.
The distributor speed for equipment that will spray 90 gallons per
minute on a roadway 12 ft. wide at an application rate of 0.33 gallons
per square yard is.
12 X '07'3'3 ~ niinute
Length of Shot. The length of spread or the length of a distri-
butor shot may be calculated by using the following formula:
L
“-A WR
26
where:
= Length of asphalt shot, feet
T = total quantity of hot binder to be shot from the
distributor, gallons
For example, if 1500 gallons of asphalt cement were to be shot at a
rate of 0.33 gallons per square yard on a roadway 12 ft. wide, the
length of shot would be
9 X 1500
12 X 0.33
= 3409
lineal ft. of roadway 12 ft. wide
Aggregate Spreading. The aggregate must be applied on top
of the asphalt in a uniform manner and at a rate equal to the design
quantity. Modern self propelled aggregate spreaders are capable of
applying a uniform quantity of aggregate at the correct rate
provided the equipment is maintained in proper operating condition.
Key steps associated with proper aggregate spreading are shown on
Table 16.
If aggregate is spread at the desired spread rate, a one
stone thick mat will result. The asphalt will be readily visible
immediately after the distribution of the coverstone if the correct
quantity has been placed. If asphalt is not visible, excess coverstone
has been applied. Construction crews will more often have a
tendency to use excess stone as opposed to using too little stone.
If insufficient quantities of coverstone are applied, aggregate pick up
by the tires of the spreading equipment or rolling equipment may result.
The rate of aggregate spreading is determined by the size of
27
opening set on the spreader box, the speed of the spreader and
aggregate characteristics including size, shape and weight. Rock
lands should be set at the start of each project in order that spreader
box opening and the spreader speed can be adjusted to give the desired
quantity. The length of the rock lands can be calculated from the
following equation:
I - M
W
where:
= Length of rock land or aggregate spread for a truck
load of aggregate, feet,
Q = Quantity of aggregate in truck load, cubic yards,
S = Aggregate spread rate, square yards of roadway surface
per 1 cubic yard of aggregate and
W = Width of aggregate distribution, feet.
For a project using 5 cubic yard trucks and spreading aggregate 12 feet
wide at a rate of 1:120 (1 cubic yard to cover 120 square yards of
roadway), the rock lands should be set at
^ ^ = 450 feet
Rolling. Rolling seats the aggregate in the asphalt and thus
promotes the bond which is necessary to resist traffic stresses. When
good quality aggregates are utilized it is nearly impossible to
over-roll a roadway. The maximum amount of rolling should be determined
by economics while the minimum amount should be set at no less than
2 to 3 coverages. Most projects find that economic rolling can be achieved
28
with 3 to 5 rollers operating in a pattern that provides from 3 to
7 coverages on each area of the roadway.
Pneumatic tired (rubber tired) rollers should be used on all
seal coats. Both pneumatic-tired and steel-wheeled rollers have
been used successfully. Pneumatic tired rollers, however, give a
more uniform pressure over the entire area while the steel -wheeled
roller will "hit" only the high spots and frequently crush the
covers tone. Contact pressures on pneumatic tired rollers can be
adjusted to minimize crushing of soft particles. Key operations
associated with rolling are shown in Table 17.
Final Clean-up. It is often necessary to remove loose aggregate
and/or excess aggregate from the newly constructed seal coat. This
operation should be performed as soon as possible to prevent stone
damage to vehicles. Power brooming is most often performed about
15 to 24 hours after construction. It is important that this
operation be performed when the binder is hard thus, the early
morning hours are preferred (Table 18),
Inspection and Quality Control. Selection of a qualified
contractor is necessary to achieve success in any construction project.
However, even with the best qualifications and intentions, mistakes
can and will be made. One way to reduce the number and impact of
such errors is to implement an adequate field inspection and quality
control plan.
Staffing of the field inspection force should be arranged well
in advance of the start of seal coat construction. Except for small
jobs, most projects will require a force of two qualified inspectors.
29
Large projects will require an even larger staff. Qualified inspectors
should have prior experience in construction and/or inspection of
similar jobs, and the supervising engineer must insist that these
inspectors be thoroughly familiar with applicable specifications,
and documents covering the project.
There are four major elements of field inspection and quality
control for seal coat projects:
1. Materials sampling and testing,
2. Construction equipment inspection,
3. Inspection of construction operations and
4. Inspection of completed road segments (performance) .
An outline of the actions recomnended for on-site materials inspection
and sampling, laboratory testing, and corrective action is given on
Table 19.
Before construction begins, the contractor's construction equipment
must be inspected to ensure specifications compliance, adequate
calibration, and good operating condition. Initial inspection can best
be accomplished at a convenient assembly point. Follow-up equipment
inspection is required each construction day. Guidelines for equipment
inspection are shown on Table 20 with additional detail given in
Appendix B as Inspectors Checklist No. 1.
During construction, the important steps of each operation must
be carefully checked. This inspection requires not only visual
observation but also certain on-site tests and measurements. Guide-
lines for inspection of construction operations are given in Table 21
with additional detail given in Appendix B which is supported by
30
Inspectors Checklists No. 2 (Asphalt Distributor Operation), No. 3
(Aggregate Spreader Operation), No. 4 (Roller Operation) and No. 5
(Brooming Operation).
Inspection of the completed job is necessary not only for final
acceptance and payment, but also to provide feedback for future seal
coat projects. This inspection should be performed in a systematic
manner and should be at regularly scheduled intervals following
constructions. Table 22 defines the types of distress and possible
causes for typical seal coat operations (23). The form shown on
Figure 12 has been utilized to evaluate seal coat performance by research
teams composed of members from the Texas State Department of Highways
and Public Transportation and the Texas Transportation Institute.
The form should be considered for use in evaluating seal coats and
will act as an invaluable training aid for inspectors.
Preconstruction, construction and performance data can be used to
revise existing seal coat design methods (19) as well as act as an
invaluable training aid for inspectors. Districts 13 and 15, among
others, have established data input forms for collecting seal coat
preconstruction, construction and performance information. These
districts should be contacted for additional information and or the
form shown in Figure 13 should be considered for use in the data
gathering effort. References 23 and 24 may be used to assist in defining
the condition of the pavement prior to placing of the seal coat.
31
SUMMARY
This manual has been prepared to provide guidelines for the
design and construction of seal. coats. If followed these guidelines
will improve the chance of successfully placing seal coats under a
variety of traffic, pavement and environmental conditions. The
manual discusses the purposes and appropriate uses of chip seal coats
and presents design, construction and performance evaluation guide-
lines. It is hoped that this manual will improve the overall performance
of seal coats in Texas.
32
REFERENCES
1. Britton, S. C., Gallaway, B. M. and Epps, J. A., "Asphalt
Surface Treatments and Seal Coats, Interim Research Report
on Project 214, Texas Transportation Institute, November
1980 (unpublished).
2. , "Asphalt Surface Treatments and Asphalt
Penetration Macadam", The Asphalt Institute, Manual Series
No. 13, November, 1969.
3. McLeod, N. W. , "Basic Principles for the Design and Construction
of Seal Coats and Surface Treatments with Cutback Asphalts and
Asphalt Cements", Proceedings, Association of Asphalt Paving
Technologists, Supplement to Vol. 29, 1960.
4. McLeod, N. W., "A General Method of Design of Seal Coats and
Surface Treatments", Proceedings, Association of Asphalt Paving
Technologists, Vol. 38, 1969.
5. Hanson, F. W., "Bituminous Surface Treatments of Rural Highways",
Proceedings, New Zealand Society of Civil Engineers, Vol. XXI,
1934-35.
6. Hanson, F. M. , "Symposium on Seal Coats on Surface Treatments
for Existing Bituminous Surfaces", Proceedings, Association of
Asphalt Paving Technologists, Vol. 24, 1955
7. Kearby, J. P., "Tests and Theories on Penetration Surfaces",
Proceedings, Highway Research Board, Vol. 32, 1953.
8. Epps, J. A. and Gallaway, B. M. , "Synthetic Aggregate Seal
Coats - Current Highway Department Practices", Research Report
83-1, Texas Transportation Institute, May 1972.
9. Epps, J. A., Gallaway, B. M. and Brown, M. R., "Synthetic
Aggregate Seal Coats", Research Report 83-2F, Texas Transportation
Institute, May 1974.
10. Draper, H. L., "Seal Coat Construction Using Cationic Asphalt
Emulsion", Phillips Petroleum Company
11. "Surface Treatment Manual Chevron Asphalt Company
12. Wright, N., "Recent Developments in Surface Dressing in the United
Kingdom, TRRL Supplementary Report 486, Transportation and Road
Research Laboratory, 1979.
13. Hveem, F. N., Lovering, W. R. and Sherman, G. B., "The Design of
Seal Coats and Surface Treatments", California Highways and
Public Works, July-August, 1949.
33
14. Benson, F. J. and Gallaway, B. M. , "Retention of Cover Stone by
Asphalt Surface Treatments", Bulletin 133, lexas Engineering
Experiment Station, Texas A&M, September, 1953
15. Kersten, M. S. and Skok, E. L. Jr., "Criteria for Seal Coating
Bituminous Surfaces", Minnesota Department of Highways, Interim
Report, University of Minnesota, 1969.
16. "1972 Standard Specifications for Construction of Highways, Streets
and Bridges", Texas State Department of Highways and Public Trans-
portation
17. Bituminous Emulsions for Highway Pavements, NCHRP Synthesis No. 30, 1975
18. Epps, J. A., Chaffin, C. W., Hill, A. J., "Field Evaluation of a
Seal Coat Design Method" Research Report 124-22, July 1980
19. "Operations and Procedures Manual", Highway Design Division, State
Department of Highways and Public Transportation, 1976 Edition.
20. "Tentative Method of Field Test for the Determination of Distributor
Spread Rate", Tentative Test Method No. Calif. 339-A, Calif. Division
of Highways, July 1963.
21. "ASTM-IP Petroleum Measurement Tables", ASTM Designation D 1250,
American Society for Testing and Materials, 1980.
22. "Construction Manual," Texas Highway Department.
23. Finn, F. N. and Epps, J. A., "Guidelines for Flexible Pavement
Failure Investigations", Research Report 214-16, Texas Transportation
Institute, July 1981.
24. Epps, J. A., Meyer, A. J., Larrimore, I. E. and Jones, J. L.,
"Roadway Maintenance Evaluation User’ s Manual", Research Report
151-2, Texas Transportation Institute, September, 1974.
34
Table 1. Potential Benefits and Problem Areas Associated With Lightweight
and Normal Weight Aggregates.
Aggregate Type
Potential Benefits
Potential Problem Areas
1 .
High skid resistance.
1 .
Aggregate degradation dur-
ing handling.
2.
Reduced windshield
2.
Abrasion resistance.
Lightweight
damage.
3.
Good color contrast
3.
Gradation control.
4.
Reduced paint stripe
4.
High water absorption.
maintenance.
5.
Higher cost.
1.
Availability and
1.
Poor skid resistance if
cost.
polish value is low.
Normal Weight
2.
Relatively low water
absorption.
2.
Windshield damage.
3.
Poor asphalt adhesion
3.
High resistance to
with high silica
degradation and abra-
aggregates .
si on .
4.
Dusting.
35
Table 2. Reconmended Aggregates for Seal Coats.
Specif i cations
Traffic Volume
Vehicles Per Day Per Lane
Item
Grade
<200
200-4000
4000-5000
Greater than 5000
301
3
X
Class A
4
X
X
5
X
X
X
302
3
X
X
Class B
4
X
X
5
X
X
X
3
X
X
303
4
X
X
Lightweight
5
X
X
X
304
3
X
X
Precoated Class B
4
X
X
5
X
X
X
305
3
X
Precoated Class A
4
X
X
5
X
X
X
X - Indicates that this grade of aggregate should not be used for
defined applications.
36
Table 3. Comparison of Asphalt Product Types Used For Surface Treatments and Seal Coats.
g; Q. O
= OJ U
•r- U
U 1/1
fO
0)
i- >, O'
3 *— C
(O •—
5 3 «—
OI </) o
3 r—
OI p—
— Q.
01 fO
a. S-
E 3
q; “O
>s 01 *0 01 *0
i- O — C fO
E (/)
+J 01
i-
-Q 01
O) o.
u E
C 01
^ 01
U
c
U I—
■O O' *r-
• P- *1- fO
/T3 01 -I- 3 0>
</» Q.
E E
01 O
<— u
•r- fO •1— 3 O'
p- C >> .—
E 3 Q.
^ \A </»
O fO M
(/» 3 W 0>r
O' Q.
O' </l
< It)
Cl O
01 4-J
WO t/J
01
3 ^
£ 3
01
3 C
•— fO
I— 01
3 ^
01 £ 3
to O LU ■!-»
i- p-
01 01 •«“ f—
^ 01 > 01
t/' •— 4. 01
p- ^sl PO
CSJ
01 O' • **“
•I- 01
Q. O
0.-M
C </> ■»-’ U 3
<— 3
O.^
CL*i-
•f- *1- T3
S I
t/>
o> -w
u ^
•<“ <tJ
3 f
0“ Q.
01 I/)
or fO
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^ CSJ PO ^
3 •»-
£ c
uj o
37
Table 4: General Recommendation for Asphalt Selection Based on Climatic
Summer - June, July, August
Fall - September, October
Winter - November, December, January, February
*Do not use in high humidity areas.
**Use caution when using dusty rock.
X-Indicates that this grade of asphalt should not be used for defined
applications.
38
Table 5. Temperature Limitations for Asphalt Selection at the Time of Construction.
Temperature Limitations °F
AC
Anionic
Cationic
Min. Surf Temp, for 2 Days Prior
70
60
60
Min. Ambient Temp, for 7 Days After
70
60
60
(With moderate traffic after construction) No rainfall in 48 hours
39
Table 6. General Recommendations for Asphalt Selection Based on Aggregate Type.
Aggregate Type*
Type of
Natural
Natural
Asphal t
Hydrophobic
Hydrophilic
Lightweight
1— oo
— J 1—
AC-5
c z
Lu
Q- s:
(jTi LU
AC- 10
cn
oo
1 — 1 •— 1
^ LO
EA-HVRS
X
X
O —I
1— 1 rs
eC LU
EA-HVRS-90
X
X
CO
o z
H-. O
EA-CRS-2
Z 1— H
O CO
1— 1 _i
h-
< s;
(_) LU
EA-CRS-2h
RC-2
RC-250
-
RC-3
LO
O
RC-4
cC
I—
n
RC-5
C_)
MC-800
MC-3000
*Aggregate classification shown on Figure 2
X-Indicates that this grade of asphalt should not be used for defined application.
40
Table 7. Asphalt Application Rate -- Correction Due To Traffic
Traffic - Vehicles Per Day Per Lane
Over
1,000
500 to
1 ,000
250 to
500
100 to
250
Linder
100
Traffic Factor (T)
1.00
1.05
1.10
1.15
1.20
Table 8. Asphalt Application Rate Correction Due to Existing Pavement
Surface Condition
Description of Existing Surface
Asphalt Quantity Correction
gal/sq. yd.
Flush asphalt surface
-0.06
Smooth, nonporous surface
-0.03
Slightly porous, slightly oxidized surface
0.00
Slightly pocked, porous, oxidized surface
+0.03
Badly pocked, porous, oxidized surface
+0.06
41
Table 9. Approximate Quantity of Cutter Stock in Cutbacks
Commonly Used for Seal Coat Operations
Type of Grade
Of Cutback
Approximate Quantity of Cutter Stock, percent
by weight
by volume
RC-2
18
23
RC-250
18
23
RC-3
11
14
RC-4
8
12
RC-5
6
9
MC-800
11
14
MC-3000
6
8
42
Table 10. Temperature -Volume Corrections for Asphalt Contents.
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® ® ® ® 0 ® CD 0 0 0 CO 0 0 CD 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 000 00000
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» ^ ^ 0 ^
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'O-O'Ow^'O'^^^mmmocNO— — — — oooooo000fs.fs.N.o-o^‘T>w^*o-^ . .
00000 00000 00000 00000 0rs.KtvN. hs.Kfv.KN. KKKKK KKKKK KKKKK KKKKK
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000 KKKKK KKKKK 00000 01
K ri K r« m m k K r« c« n k k m r» <*•«««« k r« k k r* k k k r« r« k fx in m r« r« <n <n r* cncnkmc* cn k (n n k
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^mmmm
« ©©©©© ©©©>© ©©©©© ©©©©© ©©©©© ©©©>© ©©©©© ©©©>© ©( >>> ©©©©©
I ddooo ooooo ooooo dodod dddoo ododo odddd doddd doodd ddddd
00K00 o*-rN00 00K0© 00K0© 00K00 O»Mn0 00K00
0000 OOOOO ^ mm ^ 0m ^ fm r% r* r* rt rt <n t* n 00000 00000 00000 00000
I 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000
©<0©*o rN©w>0® wvKxso — — ^ — K ^ — K^O K^OK^ OKmOK mOKmo omoom
®0®KK K0<-0'0 mmmKK 0— — — o OO©©© ®®®kk K<'<'0*r» mmmKK
-o O o ■O o -o -c o c o ^0000 o yj ■o ■o o o « © 'O O "O -o >o 0 w*> »o w^i >0 »o «o
©©©©© ©©©©© ©©©©© ©©©©© ©©©©© ©>©©© ©©©©© ©©©©© ©©©©© ©>©©©
odoco ooooo ooood oodod odood odddd dodod odddd doood ddodo
o »- i
> V « K <
10^ ® O K ® (
> © o>
<— K N — K N o K m o om©'Om © < 0 © o K®m0® v*)— ®^ — ®^—k^ OK^OK mo<mO ^ m © < m.
•O to N N m m m rs (>« — — — o O O © © ©®®®k K k ■O C •© «r> >r» m n ^ ^ m m m 0 00 — ^— 00©©©
CD®®®® ®»«®® ®®®«® ®®®KK KKKKK KKKKK KKKKK KKKKK KKKKK KK<«-<
©©©©© ©©©©© ©©©©© ©©©©© ©©©©© ©©©>© ©©>©© ©©©©© ©©©©© ©©©©©
ddddd ddodd ooood ddddd doddd odddd ddddd ddodd ddddd dddoo
®«K®» 0—00^ ®«K®» O«*00^ ®®K®» O«>00^ ®«K®^
8*>00« ®«K®» 0^00®
0000 OOOOO ^ ^
w^-“®^ — K^OKm OKmO® m©^0© *o0®m — ®^«>K'« OKmO< m©<0© ®0©*r>0 ®<rt — ®^
mm000 — — — 00 O©©©® 9KKKO ^■^^00 0000— — OOO© ©©®®® KKKO-O
OOOOO OOOOO O©©©© ©©©©© ©©©©© ©©©©© ©©©©© ©©©©® ® ® ® « « ®«®®®
OOOOO OOOOO o©©©© ©©©©© ©©©©© ©©©©© ©©©©© ©©©©©> ©©©©© ©©©©©
mm m~ m~ — — — oodo ddddo dddod ddddd oodod dodod ddddd dddco
®'«»K ^o<0© «0©00 ®0^®^ ^000^ 0©<0© 00®0 — ®«— K0 OK0O< 0©<0®
— 000© ©©®®K KK®<® 000^^ ^0000 00©©© ®®®KK K<®®0 0«*^^0
0000— — — — — — — — — — — OOO OOOOO OOOOO OOOOO
ooooo OOOOO OOOOO ooooo OOOOO OOOOO OOOOO OOOOO pppoo pooop
00000 0 0 0*
CO
©
Ol
>
o
.o
(C
o
o
CO
+J
ra
CO
fC
•r—
S-
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+J
fO
E
o
2^
>
fO
i~
O)
u
(U
c.
in
•)c
II
+->
43
Observed temperature in degrees Fahrenheit.
Multiplier for correcting oil volumes to the basis of 60°F.
Table 11. Temperature-Vol ume Correction for Cutback Asphalts.
ON.rso-0
I ^ ^ n fnr>«r«r«« —
: odddd ooddd
' ^ ^ ^ ^ ^
O CN > C>*
o o o
(O *0 1/^
d d d o d
■^ — K O fs.r)0<<n
fN fN O O O O (>
® ® ® ® ®
ooood doodd
> o rx O
« ® ® K K.
< « -O « <o
o o o d d
tf> ® K •
Utti
^ ^ O fx n O N, m o « o C <n > <o <*) > -o <»>
•n tn m o« cN r>« — O O &■ o>o>®n®
^ (nr»r-»<-ir^
® ® ® ® * 00®®®® ® ® ® ® ® ® ® ® ® ® ® ® ® ® ® ® CD ® ® ®
ddddd doddd ddodd ddddd ddodd ddddd
O *• (N n ^ ® ^ K ® »
K K K K K K K K K K • « • ® ® _.
^ ^ ^ ^
fN ® <o ^ ® ^ *— N ^ O hx M O ^ 0>®O(0>*O r<«o>w>rN®
K O « « o v-i v> ^ ^ m r> <n fN ot — — — o O O > O O ®
■O C -O 'C -O ■O'O^’OO ^ -O ■O ^ ^
®®®®® ®®®®® ®9®®® ®®®®® ®®®®®
ooddd ooooo doddd dddod odddd
0***r<m« o^c«n^
^ ^ M <s M n n f*i r« c« « <*• n m m m m n m m n m
— K^OK*«
® ® rs K K <<<o«o«o
so v-( «rj *o so so >o -o so
®®®®® ®®®®®
ddodd ddddd
55??5 ?l5;;
rx > so — ® ^ — rv fo o
> ® ® O ® *«KfNK
ooddd ooood
0^f«nT lA<^s.•>
®®w>sAw> lO «o irt
^ fn
® ® ® ® ®
ooood
rt n m r> <n
® ® ® ® ®
ddddd
® ® K ® ®
iO « ® ® ®
<n r»» r» n n
— KmO’O 4*)^<C(NO sors«®^«> N^OKn
OfNJNCs.— — OOO^ >9>®®« K rs rx <5 <3
®®«®® ®®®®K K N. rx N. tx fs,Krxhxrs.
® ® ® ® ® ® ® ® ® ® ® ® ® ® ® ® CO ® ® ®
ododd ddddd ddddd ddddd
«o«k®»s
KKKKK KKKKK ®®®®® ®®®®®
r> r» M r» n n m m
O'CfO^^ CN®sO«~®
<0 sO sO ^ ^ ^Dfnr)(N
KKKKK KKKKK
®®®®® n®®®®
ddood ddddd
S^e^«® ®®K®®
n « n « « ®®nn®
s^O-OKO- so — ® »f O
®®KK-0
I \ ooooo ooooo
i ddodd ooood
rt r> r> n r» n « r» n «
K (O o o rs< O' so — ® ^ O K o o -C K O *0 — « ^ — K r-) o <<no-w^k
(NCNK — — — O O O O O ® ® ® K K K < 'O < so <o ^
ooooo ooooo OOOO >>0^>0 OOs>o» 0‘>0‘^0‘
oooo> ooo^^ >>o^® ®®®®® ®®®®® ®®®®®
ddddo ddddo dddod dddod ddddd ddddd
0^<**nv ®®K®^ O — r* r» ^ ®®k®® o — ®®k®®
^ <N r< r* r> n r« m r< f>* r« nnmnn n n <n m m
<n r> r> (-> r» n r> n m <n rj r» n <n r» «nn®®m n n m n n
® ^ — K M O
<N K
Os
® ® ® ® ® ®
o o d d d d
O ^ « ® ® ®
^ ^ ^ ® ® ®
® n ® a ® n
•o n o -o
o o
9- 9- ^ >
® ® ® ®
d d d d
® K ® ®
V ^ ^ ®
a a a a
• K a o «o o< ®
ooooo ooooo
so — K
— O o O O
KfNtNK —
O O O O' Os
d d d o o
VI sn «i sn m
I aaaaa aaaaa
3;SS2
a a a a a
9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9
ooddd doddd ddddd ddddd
0«»aaiv a®K®® o^aa^ a®K®®
KKKKK KKKKK ®®®®® ®®®®®
aaaaa a a a a a a a a a a a a a a a
9 9 9 9 9
doddd
S«- a a ^
99 9 9
aaaaa
4 ® fS,
>9 9 9 m
- O O O O
s » 0> O. »
> d d o o
so
so
<Ts
d
o
o
LO
00
4-
o
'^(N®^ — Kf^O*>^K ®^OKa ^lO-
a a a a a a a a a a
^ O 'O a {> so ® O >ca>soK
— — O oooao- ®®KKK
a a (N a
o<f^o**^ — ®^oo a o- >o
>o >o ■v ^ ’V aaaaa — — O O ^ ^ o ® ® ® K K O -O o «o »0 »o ^ ^ a a
^ -V ^ ^ aaaaa aaaaa aa
'c^0->0>0- 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 999
' odddd dddod oddod ddood ddddd doddd ddodo ooooo dodod ododo
• aa® ®®K®® o^aav m®k®® o^aa^ ®®k®® o^aa^ ®®k®»
-1?;
aaaaa aaaaa aaaaa a a a a f
aaaaa aaaaa aaaaa aaaaa aaaaa
^ ^ ^ ♦
* a a a a aaaaa aaaaa aaaaa
K»n>soa ®^o-ca K<n o^v^a®-* o^a^so — K«0*< a®^OK oos*o — ® ■^o<a® so — Kno
V -v M 0000“0» ®®WKK K>C^soso so^^r^sn r>aaa — — ooo^ o>>®®K KK>o«^
-O-O'O'O'O >0 ■C O -O -O <> O O >0 so so >0 so so so >0 O >0 sO sO so so sO so so so so so O so O O >0 O ^ ^ ^ V ^
99999 99999 99999 99999 99999 99999 99999 99999 99999 99999
doddd ddood ddodd doodd oddod ddodo dddod ddodd doodd dodod
KKKKK KKKKK
a®'«»o^ a®^0'C r>>so — K fnoso — K r^o-oa® ^o-oa® <o — Kn> so — k«0 ■0a«^0 sOa>so —
; *Dr><-j<na a — — — o O 9 9 9 <o «kkk-« -v ^ ro r> a a a — — o OOOsOs> «®KKK sO-Osasoso
SI CO®®®® ®®®®» ®KKKK KKKKK KKKKK KKKKK KKKKK KKsC-O^ •O^'O^'O -C-C-O'O'O
!00^>0> 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9
I ddddd ooddd ddddo ddddd ddood ddddd ddddd dddod dddoo dddoo
O-Oa®^ O 'O a ® ^ O-Oa®'^ O-Ca®^ O-oa®'^ O-0a>so — koOss/^ — Kr^^s*^ — k<^>*o — K'^O’O
^<n<naa a — — OO OO-tx®® ®KKO^ sOsos-^^^ 'V o n a a a — — oo 0^0*®® •KK’O-O ^ <o so «o -v
OOOOO OOOOO 00^>0> 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 0>®®®® ®®®®® ®®®®®
OOOOO OOOOO 0>>&*0s >0*>0sCV 9 9 9 9 9 99 99 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9
— — — — — — ; — — — — oood doddd oodod odddd ddddd oddoo doood doodo
«^®K®» Q^aa®
I ® K ® ^ O * a r
t <0 K ® »
SI
— Kaosso — KmOsso — rsr^Os'O — K r> ® -v o<ia®^ o-ca®^ o-oa®^ O'Ca®^ ©"Oa®^ 0<a®^
^aaaa a — — oo 0 9 9 9 9 ®KK<^ 'Ow->so^^ ^aaaa a — — oo O>0>®® ®KK<'C -csom'^^
aaaaa aaaaa a — — — — — — _ ^ ^ — — - — . — — _ — — _ _ ^ ^ ^ _ — OOOd OOOdd OOOOO
OOOOO OOOOO OOOOO OOOOO OOOOO ooooo OOOOO OOOOO OOOOO opooq
^ 1 o ^ a f
o
o
VO
+->
03
03
•r*
s-
Ol
-t->
03
Vs-
o •
1^
>>C\I
+J
O)
u
c
O)
S-
O)
U «4-
•I- O)
<+- q;
>
03
s-
O',
o s-
cu oi
Q. -M
in v+-
■X <C
44
t = Observed temperature in degrees Fahrenheit,
n = Multiplier for correcting oil volumes to the basis of 60°F.
Table 12. Temperature- Volume Corrections for Emulsified Asphalts
1
M
1
M
1
M
60
1.00000
90
.99250
121
.98475
61
.99975
91
.99225
122
.98450
62
.99950
92
.99200
123
.98425
63
.99925
93
.99175
124
.98400
64
.99900
94
.99150
125
.98375
65
.99875
95
.99125
126
.98350
66
.99850
96
.99100
127
.98325
67
.99825
97
.99075
123
.98300
63
.99800
93
.99050
129
.98275
60
.99775
99
.99025
130
.98250
70
.99750
100
.99000
131
.98225
71
.99725
101
.98975
132
.98200
72
.99700
102
.98950
133
.98175
73
.99675
103
.98925
134
.98150
74
.99650
104
.98900
133
.98125
75
.99625
103
.98875
136
.98100
76
.99600
106
.98850
137
.98075
77
.99575
107
.98825
133
.98050
73
.99550
103
.98800
139
.98025
79
99525
109
.98775
140
.98000
30
.99500
110
.98750
141
.97975
31
.99475
111
.98725
142
.97950
32
.99450
112
.98700
143
.97925
33
.99425
113
.98675
144
.97900
34
.99400
114
.98650
143
.97875
35
.99375
115
.98625
146
.97850
36
.99350
116
.98600
147
.97825
37
.99325
117
.98575
143
.97800
33
.99300
113
.98550
149
.97775
39
.99275
119
.98525
130
.97750
120
.98500
t
M
Observed temperature in degrees Fahrenheit.
Multiplier for correcting volumes to the basis
of 60°F.
45
Table 13. Preparation Of Existing Asphalt Pavement Surface for Seal Coat
Key Steps
of Operation
Action To Be Taken
General
Pavement distress due to structural weakness
cannot be repaired by seal coating.
Pot Holes: Broken
Edges
Chip out broken material, leaving vertical sides.
Clean, prime and patch (hot mix preferred).
For hot mix patches, complete at least 30 days
before asphalt shot is scheduled. For cold
patch material, allow 60 days minimum.
Raveling: Streaking
If severe, fill depressions with slurry seal
about 30 days prior to sealing or fog seal.
Cracks-Longitudinal and
transverse
Fill large cracks with crack sealing material.
Slippage
Remove all slipped material and replace with
suitable patching material.
Bleeding Asphalt
If severe remove excess asphalt with heater-
planer or cold milling machine or heat surface
and roll-in hot aggregate.
Rutting and Corrugations
If greater than 3/4 inch remove with heater
planer or cold milling machine.
Alligator Cracking
If severe remove and replace with suitable
patching material .
Pavement Edge
Remove grass and debris build up from edge of
pavement and patch raveled edge as required.
Proper drainage should be maintained.
Cleaning
Clean surface immediately prior to asphalt shot;
remove mud and other foreign matter; sweep
thoroughly with power broom; flush with clean
water if necessary and allow to dry.
46
Table 14, Asphalt Application
Key Step
of Operation
Action To Be Taken
Equipment Check
Before work begins inspect distributor
for operating condition (Inspectors
Checklist No. 1, Appendix B).
A1 ignment
Place string-line along road edge or
use center line to guide driver of the
distributor.
Travel speed
Determine distributor speed (S^) for
spray bar output (G^)
width of shot (W) and rate of binder
application (R)
^f WR
Length of Shot
Determine length of application (shot)
(La) to balance aggregate availability
(number of loaded trucks), size of
tank, type of asphalt, allowable time
delays (asphalt shot/aggregate speed
and aggregate spread/rolling), and
traffic control.
“-A WR
Nozzle Adjustment
Adjust angle between long axis of nozzle
orifice and spray bar longitudinal axis
to value specified by distributor manu-
facturer (normally between 15 and 30 deg.)
Adjust end nozzles to greater angle
(see Figure 8). or use a deflector nozzle,
Replace clogged. or damaged nozzles.
Spray-Bar Height
Adjust height accurately to produce
exact double-lap or triple-lap pattern
determined by distributor calibration
and test. (Double-check height control
(see Figure 8) .
Spraying Temperature
Set tank heater to control temperature to
give correct viscosity for type and grade
of asphalt being shot (Table 15, Figure
9, 10, 11 , Appendix C) .
47
Table 14, Asphalt Application - Continued
Key Step
of Operation
Action To Be Taken
Transverse Joints
Avoid overlap by starting and ending
the shot applied by th? distributor
on building paper.
Longitudinal Joints
Overlap preceeding shot 1/2 width
of spray from end nozzle. Accurate
alignment by distributor driver is
essential. If a good driver is avail-
able better performance can be obtained
by using a deflector nozzle. If possible
keep joint at edge of lane it of 2-lane
highways) .
48
Table 15. Typical Temperatures for Applying, Mixing and Storing Asphalt Binders
Type of Asphalt
Appl i cation
and Mixing
Heating
and Storage
Maximum, °F
Recormiended
Range °F
Maximum
Allowable, °F
Asphal t
AC-5
275-325
350
400
Cement
AC-10
275-325
350
400
Anionic
EA-HVRS
110-150
160
160
Emulsions
EA-HVRS-90
110-150
160
160
Cationic
EA-CRS-2
110-150
160
160
Emulsion
EA-CRS-2h
110-150
160
160
Cutbacks
RC-2
125-180
200
200
RC-250
150-200
210
210
RC-3
160-210
230
230
RC-4
180-240
270
270
RC-5
215-270
285
285
MC-800
175=260
275
275
MC-3000
225-275
290
290
after reference 22
49
Table 16. Aggregate Spreading
Key Steps
of Operation
Action To Be Taken
Equipment Check
Before work begins inspect spreader
for operating condition (Inspectors
Checklist No. 1 (Appendix B)
Aggregate Supply and
Delivery
Make sure enough approved aggregate
and sufficient number of trucks are
available so that one asphalt shot
can be covered without delay.
Aggregate Moisture
Dry aggregate surface desired. On
sunny, dry days a small amount of
surface moisture on stockpiled
aggregate will be removed in the
handling operations.
Timing
Cover asphalt shot as quickly as
possible; within one minute for
asphalt cements; somewhat longer
delays are often acceptable for
asphalt emulsions and cutbacks.
Travel Speed
Depends on type of spreader. Set
and hold uniform speed to produce
specified spread rate. Avoid lopping,
bumping, or other maneuvers resulting
in non-uniform aggregate discharge.
Overl ap
Operate spreader to limit placing of
stones on top of aggregate already
spread. If excess overlap occurs
remove with hand broom as soon as
possible.
Hand Spotting
Hand spotting is normally not re-
quired. Place aggregate on bare
asphalt as required.
50
Table 17. Rolling
Key Steps
of Operation
Action To Be Taken
Equipment Check
(pneumatic rollers)
Before work begins, inspect rollers
for operating condition (Inspectors
Checklist No. 1 (Appendix B).
Particularly important: front wheel
wobble, total weight, tire pressure.
Timing
Begin rolling operations immediately
following start of aggregate spreading.
Speed
Operate so that tires do not pick up
or shove aggregate particles.
Sequence
Begin at outside edge and progress
toward center. Overlap preceding
pass by about 1/2 rolling width.
Make at least 2 to 3 coverages.
The first coverage should be completed
soon after application of the aggregate.
Avoid tight turning movements and
sudden stops and starts.
Table 18. Final Clean-Up
Key Steps
o.f Operation
Action To Be Taken
Timing
Begin power brooming only after
aggregate is completely set and
asphalt has hardened usually at
least 24 hours after rolling is
complete. Operate broom when
pavement surface is cool preferably
in the early morning hours.
Sequence
Operate power broom to lightly brush
loose stones toward outer edge of
lane. Bonded stones should not be
dislodged.
51
Table 19. Guidelines for On-Site Materials Inspection and Sampling
Materials
Action To Be Taken
Cover Aggregate 1 .
2.
3.
4.
5.
6.
7.
Asphalt Binder 1 .
2.
3.
4.
5.
6.
Take representative sample from
each stockpile.
Quarter each stockpile sample.
Test one quartered sample from
each stockpile.
Label and retain unused samples.
Check test results against
a) Specifications
b) Acceptance tests made prior to
del ivery
c) Test data used for design
Take appropriate action if:
a) Significant deviations in test
data are noted
b) There is significant pile-to-
pile variation in test results
Inspect piles for drainage and
cleanliness
Make visual check for excess
moisture before aggregate is loaded
into trucks
If asphalt storage and distributor
tanks are not clean and empty when
placed on the project, take a
representative sample of the material
in each tank.
Have each sample tested to establish
the type and grade of asphalt
remaining in each tank.
If the type and grade of asphalt in
a tank does not correspond to the
type and grade specified for the
project, the tank must be drained
and cleaned before refilling.
Carefully check delivery document
for each load of asphalt delivered
to the site to ensure application
of the proper type and grade.
Make visual check for separation
before loading asphalt emulsions
into the distributor tank.
The inspector should take samples
and have them tested if- he has
reason to believe that contamination
of the asphalt has occurred.
52
Table 19. Guidelines For On-Site Materials Inspection and Sampling - Continued
Material s
Action To Be Taken
7. Obtain D-9 test number for asphalt
shipments and obtain viscosity-
temperature data from Division 9
in Austin. Plot on Figure in
Appendix C.
53
Table 20. Guidelines for Construction Equipment Inspection
Inspection Timing
Action To Be Taken
Prior to Starting
Construction
1 . Make sure numbers of each kind of
construction equipment assigned
are adequate for project scope
and schedule.
2. Check each piece of equipment for:
a) Specification compliance,
b) Required calibrations and
adjustments ,
c) Operating condition.
3. Check against Inspectors Checklist
No. 1 , Appendix B.
At Beginning of Each
Construction Day
1. Check operating condition, use
Inspectors Checklist No. 1,
Appendix B
54
Table 21. Guidelines for Inspection of Construction Operations
Operation and
Step Inspected
Existing Asphalt
Pavement Surface
Asphalt Distribution Rate
Asphalt Distributor
Aggregate Spread Rate
Action To Be Taken
Visual inspection for repair of
defects (pot-holes, cracks, etc). All
patching should be completed 30 to 60
days before seal coating begins.
Inspect for cleanliness.
1. On first shot, then periodically
during job, measure transverse
variation in rate by catching
spray on cotton pads spaced across
pavements. Appendix A. Transverse
variation in rate should be less
than 15 percent for asphalt
emulsions and less than 10 percent
for asphalt cements and cutbacks.
2. On first shot, then periodically
during job, measure longitudinal
variation in spray rate by catching
asphalt in 12 in. x 12 in.
shallow paper-lined pans placed at
100 to 150 ft. intervals along the
direction of travel. The longitu-
dinal variation in rate should be
less than 10 percent.
3. By gauging tank before and after
shot, determine total asphalt
applied (T) and calculate distri-
bution on a gallons per square yard
basis .
R = ^ gal/yd^
Inspect as indicated in Inspectors
Checklist No. 2, Appendix B.
1. Check spreader adjustment before
first application. Place 1 yd*^
pans (or cloths) at intervals across
spread width and operate spreader
over these. Average of weights
retained in the pans should equal
the design spread rate. Transverse
variation in spread rate should be
less than 10 to 15 percent.
55
Table 21. Guidelines for Inspection of Construction Operations - Continued
Operation and
Step Inspected Action To Be Taken
2. Use tachometer to assure spreader
box speed control.
3. Check spread rate by laying off
road length for each truck load
of aggregate.
Aggregate Spreader Operation Inspect as indicated in Inspectors
Checklist No. 3, Appendix B
Inspect as indicated in Inspectors
Checklist No. 4, Appendix B
Inspect as indicated in Inspectors
Checklist No. 5, Appendix B
Roller Operation
Brooming and Other
Cleaning Operations
56
Table 22. Types and Causes of Seal Coat Distress
Distress
Possible Causes
Streaking
Corduroying
Incipient Bleeding
Ravel ing
Transverse Joints (Bumps)
Longitudinal Ridges
Longitudinally distributed deficiencies
in asphalt application due to: inopera-
tive nozzles, incorrect nozzle angles,
incorrect distributor bar height, low
asphalt temperature, low pump pressure,
incorrect fan widths at a given height,
high distributor speed. These problems
are particularly troublesome at spread
rates below 0.1 gal/yd. 2
Uneven and bumpy aggregate spreader
operation. Bent or warped roll base.
Underlying surface condition (too soft,
inadequate preparation, excess asphalt
not removed, base not compacted, primer
incorrectly applied). Asphalt spread
rate too high. Asphalt spread rate
OK, but aggregate spread rate too low. .
Aggregate loss due to moisture problems.
Asphalt spread rate too low. Aggregate
loss due to moisture problems. Fast
traffic allowed on surface too soon.
Overlap of asphalt at beginning and end
of a shot.
Too much overlap of asphalt and aggregate
spread which results in excesses of one
or both materials.
57
■O
O) S-
+-> O
ro •+-
to >,
to I—
58
10
pH OF WATER IN CONTACT WITH AGGREGATE
9 8 7
SILICEOUS LIMESTONES
LIMESTONES
HYDROPHOBIC
L
20
FIRED CLAY
< ►
PORPHYRIES
LIGHTWEIGHT
AGGREGATES
SILICA
H ►
BASALTS
\< H
TRAP ROCK
CHERT
FLINT
SANDSTONES
DIORITES
h *-1
OPHITES
k H
GRANITES
k
»4^MIXED*4< HYDROPHILIC
J L
40 60
SILICA CONTENT, %
80
100
100
Figure 2.
80
60 40
ALKALI CONTENT, 7o
Agoregate Type Classification Chart.
(After Reference 17.)
20
59
AVERAGE MAT THICKNESS, INCHES
Figure 3. Relation of Percent Embedment to Mat Thickness for Determining
Quantity of Asphalt.
60
POWER DRIVEN PUMP
baffle plate
VALVE CONTROL
burners
Figure 4. Asphalt Distributor.
(After Reference 2.)
Self-Propelled Aggregate Spreader
now of Aggregate Through a Self-Propelled Spreader
Figure 5. Aggregate Spreader.
(After Reference 2.)
61
Fiyur© 6. Pn6um3tiC"Tir6d RoIIbt.
Figure 7. Power Broom
62
NOZZLE SPACING
K ►-<-
SPRAY BAR
TRIPLE _LAJ3
^OZZLE^'
SPACING
X = THEORETICAL LAP FOR
GOOD LONGITUDINAL JOINT
USING DOUBLE COVERAGE
SPRAY PATTERN
Y= THEORETICAL LAP FOR
GOOD LONGITUDINAL JOINT
USING TRIPLE COVERAGE
SPRAY PATTERN
SPECIAL
END NOZZLE
PAVEMENT
SURFACE
SPRAY BAR
TRAVEL
ROAD SPRAY PATTERN
FIGURE 8. DESIRED SPRAY BAR HEIGHT AND NOZZLE ANGLES
(After Reference 2)
63
FIGURE 9. DISTRIBUTOR OPERATING TEMPERATURE LIMITS FOR ASPHALT
CEMENTS AND CUT- BACKS
(AFTER REFERENCES 3 AND 4)
NOTE * ESTIMATES ONLY. THIXOTROPIC BREAKDOWN OF ASPHALT EMULSIONS IN PUMPING
OR SPRAYING MAKE VISCOSITY LIMITS DIFFICULT TO ESTABLISH.
FIGURE 10. DISTRIBUTOR OPERATING TEMPERATURE LIMITS FOR ASPHALT EMULSIONS
VISCOSITY, POISES
Figure 11. Viscosity-Temperature Chart.
1 poise = 100 centi poise
65
Figure 12. Chip Seal Evaluation Form.
LOCATION
CHIP SEAL EVALUATION
State County.
Mile Post or Station Limits: From
Section Identification Number
Highway
To
CONDITION
Overal 1
Condition
AGGREGATE
RETENTION
Outer Wheel Path
Inner Wheel Path
Between Wheel Path
Center! ine
BLEEDING ~~j
Outer W.heel Path
Inner Wheel Path
Between Wheal Path
Centerline
AGGREGATE EMBEDMENT S |
SURFACE TEXTURE j
Outer Wheel Path _
Inner Wheel Path
Between Wheel Path
Centerline
OTHER INFORMATION
Skid Number SN^q
SN
SN
Rater (s)
Poor
Fai r
Good
-| r-
4
8
100
I r
Percent Aggregate Loss
50 25 15 10 5
1 r-
2
1 r
4
8
oevere
Moderate
SI ight
8
1 ?”
4
I 1
ibedment
Texture
cu. in./sq. in.
cu. in./sq. in.
cu. in./sq. in.
cu. in./sq. in.
Comments ,
Date
10
10
10
To
To
To
To
To
To
66
Figure 13: Data Gathering Form For Seal Coats
Location ^ District County Highway
Mile Post or Station Limits: From To
Section Identification Number
Lane
Preconstruction j Type of Surface on Old Roadway
Condition of
Rutting
Alligator Cracking
Old Surface:
Raveling
Longitudinal Cracking
FI ushinq
Transverse Cracking
Corrugations
Patching
Deflection;
Mean
Std. Deviation
Range
No.
Road Roughness:
Mean
Std. Deviation
Range
No.
Skid Number:
Mean
Std. Deviation
Range
No.
Surface Texture: Outer Wheel path Between wheel path
Inner wheel path Centerline
Traffic: ADT Per Lane % Trucks Eq. 18 Kips per lane
^
Design [
Type of Asphalt D-9 Test No
Type of Aggregate Source of Aggregate
Design Asphalt Quantity Gallons per sq. yd.
Aggregate Quantity 1: Square yards
Construction
Asphal t Shot: Mean
Std. Deviation
Range
No
Temperature of Shot:
Aggregate Quantity: Mean
Std. Deviation
Range
No
Climatic Conditions: Temperature Low
High
Rainfall: Day Before Construction
Day of Construction
Day After Construction
2 Days After Construction
67
Figure 13: Data Gathering Form For Seal Coats
Continued
Date(s) of Construction: From To
Performance
Date
Overal 1
Aggregate
Retention
Bleeding
Aggregate
Embedment
68
APPENDIX A
TENTATIVE METHOD OF FIELD TESTS FOR THE
DETERMINATION OF DISTRIBUTOR SPREAD RATE
69
State of California Tentative Test Method No. Calif. 339-A
Oepo'^Tient of Public Works MATERIALS AND RESEARCH DEPARTMENT July, i963
Division of Highways (5 pages)
TENTATIVE METHOD OF FIELD TEST FOR THE DETERMINATION
OF DISTRIBUTOR SPREAD RATE
Scope
This description covers tlic jirocednre for determin-
ing: the transverse and lontritndinal spread rate in
pallons per square yard of bituminous distributors.
PART i. TRANSVERSE SPREAD RATE
DETERMINATION
Procedure
A. Apparatus
1. Balance sensitive to 0.1 g.
2. Suitable weighing box or shield for balance.
3. Metal sheets 77s" x 60" — 20 gauge galvanized.
4. Balance table and work table.
B. Materials
1. Absorbent panels. There are seven 4" x 8" absorb-
ent cotton pads attached to each panel with perfora-
tions between each pad so that they may be easily
separated. These may be obtained from Service and
Supply.
Note: The above panels may be prepared, if not available, by
oenjentinp 4" x 8" cotton pads (Bauer & Black, No. 540 .sponges,
4" 1 4") to suitable heavy weight paper. Each panel should be
16"' 1 28". The panel should be perforated accurately at 4"
intervals at right angles to the 2S" length, prior to attaching
the pads. It should also be creased the long way so as to leave
i.a S" .X 28" .'irea in the center. Fig. I. Panels may be perfo-
rated down the center the long way to facilitate folding after the
binder has been caught.
C. Materials (Alternate Method)
1. Cotton pads 4" x 8". These are sold by Bauer &
Black, Xo. 540 Sponges 4" x 4" (they are de.signated
as 4" X 4" but open out into 4" x 8").
2. 5" X 10" strips cut from heavy v.rapping paper.
3. 77s"n60" sheets cut from 20 gauge galvanized
metal scribed at 4" intervals after the first one at 5".
4. Masking tape, y<i' width.
5. Suitable adhesive for fastening cotton pads to
paper ; latex, rubber cement or asphalt emulsion have
been used.
D. Prepaiation of Test Plates
1. Remove several individual pads from a panel and
weigh to determine the average tare weight. The re-
mainder of the panel may be used for the longitudinal
spread determination.
2. Fold 2 absorbent panels. Fig. I, over each metal
sheet with the cotton pad side out. One end of panel
must be flush with the end of the metal sheet. Place
second panel snug against end of first panel.
3. Secure panels to metal sheet with tape on reverse
side of sheet.
E. Preparation of Test Plates (Alternate Method)
1. Attach the 5" x 10" paper strips to the metal
sheets with masking tape, eaeli strip overlapping the
adjacent strip 1 inch.
2. After all the paper strips have been attached to
the metal sheets coat the top surface uniformly with
the adhesive. Theu place the cotton pads on the paper
so that each pad covers exactly the exposed 4"x8"
paper surface. Fig. II shows the paper strip and part
of the cotton pads in place.
3. Weigh several of the pads with the paper back'-'g
attached after they are tlioroughly dry to determine
the tare weight.
F. Sampling
1. As the distributor approaclies, place the test
plates across the roadway; see Figs. Ill and IT". In
laying the plates across the pavement it is good prac-
tice to place the bare ends towards the shoulder side
of the lane. This procedure will facilitate removal
from the pavement and aid in keeping the pads in
proper sequence.
2. As soon as the distributor has passed remove the
test plates from the pavement. When the procedure
involves the use of absorbent panels, (see B-1) remove
the panels, fold along the center line and then remove
each pad by tearing along the perforations. In the
case of test plates prepared by the alternate method,
place the entire assembly on a rack, (see Fig. V) then
remove and fold each pad and paper strip. In order
to properly identify the pads and expedite weighing
operations, number the pads on the back side of the
test plate .starting with pad Number 1 nearest the
center line of the pavement. Remove the pads in order
starting with the pad nearest the shoulder line and
stacking each pad on the previous one .so that the stack
will be completed on removal of the pad numbered one
that is nearest the center line.
3. As soon as the removal operation is completed
place the pads in the Aveigh box, and then weigh in
order to the nearest 0.1 g; see Figs. VI and VII.
Record the xveight of each pad on Form T-3025, (Rev.
1-60) starting the recording with pad X'o. 1, the pad
nearest the center line of the pavement. If a tare is
used during weighing, then record the net weight of
tlie bitumen in column 2 of Form T-3025, otherwise
the previously determined average Aveight of the indi-
vidual pads must be subtracted from the total Aveight
of pad bitumen.
G. Calculations
1. ^Multiply the net Aveight of binder on each pad by
0.0107, or use the attached table to obtain the spread
rate in gal./sq.yd. The conversion table is also found
on the back side of Form T-3025.
2. Determine the average spread rate in gal./sq.yd.
by dividing the total quantity of binder collected on
the pads by the number of pads. Omit end pads that
shoAv very Ioav spread rates due to feathering and also
end pads shoAving a heaA'y rate due to the use of
shields. Normally those to be ebminated can be de-
70
Tentative Test Method No. Calif. 339-A
July, 1963
termined by inspection but if a more uniform method
is desired the following procedure raa}' be used :
Calculate the average spread rate using all pads
having a binder content of over 0.05 gal./sq.yd. Omit
all end pads varying more than 15% (plus and
minus), then recalculate the average spread rate.
3. For further study plot the test results together
with the average spread rates and the specified limits.
H. Precautions
1. Do not allow traffic to drive over the sample pads
(the relatively slow moving distributor does not dis-
turb the test plates).
2. In very hot weather, remove and weigh the
sample pads in the shade and with as little delay as
possible. If substantial delay occurs, prepare a control
sample with a known weight of binder and weigh at
intervals to determine the evaporation loss rate and
a correction.
I. Notes
A light metal camp table has been found very useful
in removal and separation of the sample pads; see
Fig. V. Since all weighing must be done at the job
site and as rapidly as possible it has been found best
to use a separate table for the balance. The balance
is placed inside a specially constructed box (available
from Service and Supply) so that the operator can
work with his hands and forearms inside; see Fig.
VII. A small torsion balance IL5 graduated to 0.1
gram available through Service and Supply will fit
in this box. The quantity on each pad, in gal./sq.yd.,
should be recorded or plotted directly on graph paper.
A convenient graph paper has been found to be one
having a scale 12 x 20 to the inch, such as Kueffel and
Esser Co. Xo. 359-21.
PART II. LONGITUDINAL SPREAD RATE
DETERMINATION
A. Apparatus
1. Balance sensitive to 0.1 g.
B. Materials
1. Absorbent panels.
2. Cotton pads 4" x S", of the same type used for
transverse measurements (see C-1 of Part I).
3. 5" X 10" strips cut from hea^y wrapping paper.
4. 7;^" X 12" sheets cut from 20 gauge galvanized
metal.
5. Masking tape, width.
G. Suitable adhesive for fastening cotton pads to
paper (see C-5 of Part I).
C. Preparation of Test Plates
1. Remove a section of three pads from the trans-
verse pad panel, see Pig. 1, by tearing along a line
of perforations.
2. Secure panel containing the three pads to the
metal sheet using tape on the reverse side of sheet.
3. Determine tare weight of pads, and if desireil,
prepare a tare weight.
D. Preparation of Test Plates (Alternate iMethod)
1. Attach cotton pads to the 5" x 10" paper strif>.s
with adhesive, leaving a 1" margin on three sides;
see Fig. VIII.
2. Fasten three paper strips with attached ]>ads
to the metal sheet by folding the ends over the sheet
and attaching with masking tape. Each successive
strip overlaps the exposed paper on the previously
fastened strip; see Fig. VIII. Trim off the excess 1"
edge of the last paper backing strip that extends over
the metal .sheet.
3. Weigh several of the pads with the paper back-
ing after they are thoroughly dry and determine The
average tare weight.
4. Prepare a tared weight if desired for u.se in
weighing.
E. Sampling
1. Place test panels at not less than 100 foot inter-
vals and equidistant from the centerline and edge of
pavement.
2. After the distributor has passed, remove pads
from metal sheets and weigh to nearest ± 0.1 g. (St*e
F. Sampling, of Part I.)
F. Calculations
1. Subtract the tare weight of the pads and mul-
tiply the total net weight of the binder on the 3 pads
by 0.00356 to obtain the spread rate in gals, per sq.
yd., or determine the average for one pad and use
the attached table.
G, Precautions
1. Care should be taken to jdace all the sampling
units equidistant from the center line or edge of pave-
ment in order that the same jets of the distributor
will pass over all the sampling units.
REFERENCE
A California Mi‘lho<l
End of Text on Calif. 339-A
71
Tentative Test Method No. Calif. 339-A
July, 1963
CONVERSION TABLE
Net wt. of binder on 4" x 8" pods to goU./tq. yd.
grams
.0
.1
.2
.3
4
.5
.6
.7
.8
.9
s
.086
.087
.088
.089
.090
.091
.092
.093
.094
.095
9
.096
.097
.098
.099
.100
.102
.103
.104
.105
.106
10
.107
.108
.109
.110
.111
.112
.113
.114
.116
.117
11
.118
.119
.120
.121
.122
.123
.124
.125
.126
.127
12
.128
.129
.131
.132
.133
.134
.135
.136
.137
.138
13
.140
.141
.142
.143
.144
.146
.147
.148
.149
14
.150
.1.51
.152
.153
.154
.155
.156
.157
.158
.1.59
15
.160
.162
.163
.164
.105
.166
.167
.168
.109
. .170
16
.171
.172
.173
.174
.175
.177
.178
.179
.180
.181
17 — -
.182
.183
.184
.185
.186
.187
.188
.189
.190
.192
18
.194
.195
.196
.197
.198
.199
.200
.201
.202
19
.203
.204
.205
.206
.208
.209
.210
.211
.212
.213
20
.214
.215
.216
.217
.218
.219
.220
.221
.223
.224
21
.225
.226
.227
.228
.229
.230
.231
.232
.233
.234
22
.235
.236
.237
.239
.240
.241
.242
.243
.244
.245
23
.246
.247
.248
.249
.250
.251
.252
.2.54
.255
.250
24
.2.57
.258
.259
.260
.261
.262
.203
.264
.265
.266
25
.267
.209
.270
.271
.272
.273
.274
.275
.276
.277
26
.278
.279
.280
.281
.282
.284
.285
.286
.287
.288
27
.289
.290
.291
.292
.293
.294
.295
.296
.297
.298
28 —
..300
.301
.302
.303
.304
.305
.306
.307
.308
.309
29
.310
.311
.312
.313
.315
.316
.317
.318
.319
.320
30
.321
.322
.323
.324
.325
.326
.327
.328
.330
.331
31
..332
.333
.334
.335
.336
.337
.338
.339
.340
.341
.32
.342
.343
.344
.346
.347
.348
.349
.350
.351
.3.52
33 —
.353
.354
.355
.356
.357
.358
.359
.361
.362
.303
34 — .
.364
.365
.360
.367
.368
.369
.370
.371
.372
.373
35
..374
.376
.377
.378
.379
.380
.381
.382
.383
.384
TEST PANEL
FIGURE II
TEST PANEL— ALTERNATE METHOD
FIGURE I
FIGURE III
TEST PLATES IN POSITION FOR TEST
FIGURE IV
DISTRIBUTOR JUST BEFORE PASSING OVER TEST PLATES
72
Tentative Test Method No. Calif. 339-A
July, 1963
FIGURE V
FIGURE VI
REMOVING PADS FROM STEEL PLATE,
ALTERNATE METHOD
WEIGHING BOX
FIGURE VII
WEIGHING PADS— NOTE PAD STACK INSIDE BOX
FIGURE VIII
PLACING OF 4" x 8" COHON PADS
ON METAL SHEET
73
Tentative Test Method No. Calif. 339-A
July, 1963
MATERIALS 8 RESEARCH DEPARTMENT
TRANSVERSE a LONGITUDINAL DISTRIBUTOR SPREAD RATES
TEST BY SHEET NO.
PAD
NO.
PAD WEIGHT
SPREAD
RATE
GALS./ YD.
OUTSIDE
LIMITS
Contract *Date
GROSS
GRAMS
NET
GRAMS "
Co. Rte. Sec.
Contractor R.E.
1
Dist. Owner Wo.
2
Sta. Lane
3
Type Binder Temp.
4
5
uibi. uunui 1 lu
1
6
opec. opreaa L>ais./ba. Ya.
7
Tank Gauginc
Direction of C
Gals./
Sq. Yd.
8
listributor
9
CALCULATIONS
TRANSVERSE SPREAD
10
1 1
. _ Total gals/yd (omitting end pads*)
12
13
Na of pads
Ava. = Gals./Sa. Yd.
14
15
16
Ava. +15% Gols./Sa. Y
d.
17
18
Ava. -lo Vo bais./ba. Yd.
*See Section G, Calculations of Part I
19
20
21
22
LONGITUDINAL
23
24
orncMu uc.
C. mvi ! 1 1
25
TARE =
GRAMS
SPREAD
RATE
GALS / YD.
OUTSIDE
LIMITS
26
GROSS
GRAMS
NET
GRAMS
27
28
29
30
31
32
33
Constants, etc.
Start from <i. pavement at top of poge.
Pad Tare = arams.
Binder on pad x 0.0107 = gals. /sq. yd.
34
35
36
37
38
39
40
TOTALS
form T-3025 (REV. 1-60)
FIGURE IX
74
APPENDIX B
INSPECTOR CHECKLISTS
75
Inspectors Checklist No. 1 - Construction Equipment
Asphalt Distributors
1. Do distributors assigned to the job meet specifications requi rements?
2. Are heaters and pumps in good operating condition?
3. Are certified calibrations for tank, tachometer and other measuring
devices available?
4. Are spray bars and nozzles in good condition, clean and correctly
adjusted?
5. Have all other adjustments been made in accordance with manufacturers
instructions?
6. Has rate of application (including transverse and longitudinal
variation) been checked?
7. Will spray bar height adjustment give required double-lap or triple-
lap spray pattern with nozzle set as installed?
8. Does distributor have a means of maintaining constant spray bar
height? Is it in good operating condition?
Aggregate Spreaders
1. Do spreaders assigned to the job meet specification requirements?
2. Has spreader operation been checked, including spread rate and
transverse and longitudinal variation?
3. Can aggregate trucks assigned to the job be connected quickly and
positively to the spreader?
4. Have all other adjustments been made in accordance with manufacturers
instructions?
76
Checklist No. 1 (continued)
Rollers (pneumatic)
1. Do rollers assigned to the job meet specification requirements?
2. Are total weight and tire pressures within limits specified for
the job?
3. Can each roller start, stop and reverse smoothly?
4. Are wheelbearings free from excessive wear?
5. Do the wheels track properly? Are they free from excessive wobble?
Cleaning Equipment
1. Are boom bristles in good condition - clean and free from
excessive wear?
2. Does the power drive on all brooms operate properly?
3. Are blowers operating properly?
4. Are fl usher nozzles free from obstructions and operating properly?
77
Inspectors Checklist No. 2 - Asphalt Distribution Operation
1. Is stringline or centerline in place for all distance of shot? Is distributor
guideline marker correctly in place?
2. Is asphalt temperature in distributor tank at correct value?
3. Is sufficient quantity of asphalt in the distributor tank to make the
full shot?
4. Are pump pressures and travel speed set to produce specified asphalt
application rate?
5. Are all nozzles open and set at correct angle?
6. Is spray bar set at correct height?
7. Is paper in place at beginning and end of shot? Is it held down so it
will not be disturbed by wind or distributor passage?
8. As shot begins and throughout the shot, visually check flow for uniformity
over full width. If streaks appear, stop distributor and correct the
trouble. Streaking is usually caused by improper spray bar height
adjustment, improper asphalt temperature, or worn or clogged nozzles.
Use of worn or clogged nozzles should not be tolerated. Nozzles should
only be cleaned by soaking in kerosene or other solvent and air blowing.
Nozzles should not be cleaned by insertion of a wire into the orifice.
9. Does outside edge of application coincide with stringline or centerline
over full length of shot?
10. Make sure that flow of asphalt is cut off as soon as distributor crosses
paper at end of the shot and that distributor is backed up so that any
nozzle drip will fall on paper.
11. After gaging tank at end of shot, calculate average spread (R) corrected
back to 60°F. If this value does not coincide with design (A), within
specified limits, make necessary adjustments so correct spread rate
is delivered on subsequent shots.
78
12. Where pavement width on curves is larger than on tangents, make
sure that extra material for the widening is applied on the upper
side of the roadway instead of the lower side (inside the curve).
79
Inspectors Checklist No. 3 - Aggregate Spreader Operation
1. Are surfaces of aggregate particles free of moisture?
2. Are trucks loaded with sufficient aggregate to cover the asphalt
shot before shot is begun?
3. Has asphalt shot been completely covered with aggregate within
required time limit?
4. Does the spreader distribute aggregate uniformly over the entire
width and length of the asphalt shot?
5. Is the operator avoiding excess overlap of aggregate spread on the
surface?
6. Is the spreader operator holding a constant speed, without bumping,
jerking, or loping?
7. Do trucks hitch and unhitch with the spreader quickly, positively,
and without bumping or jerking?
80
Inspectors Checklist No. 4 - Pneumatic Roller Operation
1. Just before rolling operation begins: are all tire pressures
adjusted to the specified value?
2. Does rolling begin immediately after the aggregate has been placed
on the surface?
3. Is a proper rolling sequence being followed?
4. Are at least 2-3 coverages being made?
5. Is roller operating speed held so that tire pickup does not occur?
6. Does the operator start, stop, and reverse the roller smoothly?
7. Are all tires tracking properly without wobble?
81
1. Is asphalt mat completely hardened before cleaning operations
begin? (A 24 hour delay after rolling may be necessary).
2. Is broom pushing loose particles toward the edge without moving
or dislodging aggregate embedded in the asphalt mat?
3. Does the broom (or other cleaning operation) remove nearly all of
the loose particles?
82
APPENDIX C
Viscosity-Temperature Chart
83
viscosity, poises
VISCOSITY - TEMPERATURE CHART
0 O JO 40 W ttO ro •(> «0 lOO Ito ISO l>0
■O so so 40 so «0 70 «0 «000i)0 40ix>i40ts0>«0i70[«0t«0 200 s>0 220 230 240 210 2«0
TEMPERATURE. DEGREES FAHRENHEIT
270 220210SOO SO120S90S40S90M0S70M0 S«0 400
84
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