EPA-670/2-74-014
March 1974
Environmental Protection Technology Series
SCRAP RUBBER TIRE UTILIZATION
IN ROAD DRESSINGS
lesearch Center
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
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EPA-670/2-74-014
March 1974
SCRAP RUBBER TIRE UTILIZATION
IN ROAD DRESSINGS
By
Benson G. Brand
BATTELLE-Columbus Laboratories
Columbus, Ohio 43201
Project Element No. 1DB314
Project Officer
Richard A. Carries
Solid and Hazardous Waste Research Laboratory
National Environmental Research Center
Cincinnati, Ohio 45268
NATIONAL ENVIRONMENTAL RESEARCH CENTER
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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REVIEW NOTICE
The Solid Waste Research Laboratory of the
National Environment Research Center - Cincinnati,
U.S. Environmental Protection Agency, has reviewed
this report and approved its publication. Approval
does not signify that the contents necessarily re-
flect the views and policies of this laboratory or
of the U.S. Environmental Protection Agency, nor
does mention of trade names or commercial products
constitute endorsement or recommendation for use.
The text of this report is reproduced by the
National Environmental Research Center - Cincinnati
in the form received from the Grantee; new
preliminary pages have been supplied.
11
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FOREWORD
Man and his environment must be protected from the
adverse effects of pesticides, radiation, noise and other
forms of pollution, and the unwise management of solid
waste. Efforts to protect the environment require a
focus that recognizes the interplay between the com-
ponents of our physical environment—air, water, and
land. The National Environmental Research Centers
provide this multidisciplinary focus through programs
engaged in
o studies on the effects of environmental
contaminants on man and the biosphere, and
o a search for ways to prevent contamin-
ation and to recycle valuable resources.
The study described here was undertaken to demonstrate the
feasibility of using rubber from discarded passenger car tires
in emulsions as blacktop dressings for driveways. Employing
rubber in this manner could increase the demand for used tires
and decrease their solid waste disposal problem.
A. W. Breidenbach, Ph.D.
Director
National Environmental
Research Center, Cincinnati
iii
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EXECUTIVE SUMMARY
The objective of this study was to demonstrate the feasibility of
using rubber obtained from discarded passenger car tires in water-thinnable
emulsions of asphalt or coal tar for blacktop dressings fqr driveways,
parking lots, streets, highways, etc. The use of rubber in this large volume
market could result in an increased demand for the used tires, and, thus,
decrease the solid waste disposal problems connected with 200 million dis-
carded tires per year.
The study has resulted in the production of nine different com-
positions containing from 5 to 25 percent rubber that were promising enough
to apply to a high-traffic area in the BCL parking lot (estimated passage of
1800 cars per day), to determine the respective service lives of the composi-
tions.
After exposure for one year under the above conditions, performance
appears to have been as good as that of the control samples, and protection
of the underlying blacktop is still being rendered by all samples.
The goal of the project was the demonstration of the feasibility
of the basic idea that rubber salvaged from discarded auto tires could be
incorporated into water-thinned blacktop dressings, and to utilize the in-
formation obtained to generate interests of industrial companies continuing
the studies to result in marketable products.
It is felt that the goals of this study have been fully met. Complete
feasibility of the basic idea has been demonstrated. Service-life demonstration
have shown good performance characteristics, even though no attempts were made
to optimize the formulation. One proposed research program was supplied to a
government agency at their request. This was technically approved but funding
could not be arranged. Two additional proposals have been submitted to in-
dustrial companies, and are currently under consideration.
Future plans for Battelle activity in this area will involve attempts
to interest industry in continuing the study to develop improved materials.
iv
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TABLE OF CONTENTS
Page
INTRODUTION 1
SUMMARY 1
BACKGROUND 2
INDUSTRY SURVEY .' . 4
DESCRIPTION OF SAMPLES 5
Rubber Reclaimers Association Samples 5
Union Carbide Sample 6
Baker Samples 6
Phoenix Sample 7
Uniroyal Dispersion 8
Porter Sample 8
Tall Oil Pitch 9
Asphalt Emulsion Base ..... 9
Coal Tar 9
EXPERIMENTAL 10
Incorporation of Rubber into Asphalt and
Coal Tar 10
Emulsification of Rubberized Asphalt 13
Rubberized Coal Tar Emulsification 14
Preparation of Experimental Emulsions for Exterior
Evaluations 17
Weather-0-Meter Studies 19
Weather-0-Meter Evaluations ..... 19
Slip Resistance of Experimental Emulsions 22
Application of Nine Experimental and Two
Control Emulsions 24
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TABLE OF CONTENTS (Continued)
Page
Three-Week Evaluation of the Applied
Experimental Emulsions 24
Subsequent Evaluations 27
CONCLUSIONS 29
PATENTS 30
FUTURE WORK 32
LIST OF TABLES
Table 1. Incorporation of Rubber into Asphalt and Coal
Tar 11
Table 2. Emulsified Asphalt-Rubber Mixtures 13
Table 3. Emulsified Coal-Tar Rubber Mixtures 16
Table 4. Experimental Emulsions for Exterior Exposure ..... 17
Table 5. Weather-0-Meter Evaluation of Experimental
Emulsions 20
Table 6. Slip Resistance of Experimental Emulsions 23
Table 7. Three-Week Evaluation of Experiment and Control
Emulsions 24
LIST OF FIGURES
Figure 1. Evaluation of Site Before Application 25
Figure 2. Evaluation Site After Application 25
APPENDIX
vl
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INTRODUCTION
Battelle's Columbus Laboratories has carried out research under Grant
No. R-EP-00500-01 having the following objective: to explore the feasibility
of effective and advantageous use of ground scrap or reclaimed rubber from
discarded rubber tires that now present a sizeable disposal problem. The
research was directed toward this objective by studying the development of
improved water-thinned blacktop dressings through incorporation of the rubber
salvaged from used passenger car tires in a bituminous (asphalt or coal tar) base.
SUMMARY
An exploration of the rubber industry has shown a wide variety of
products is available or can easily be made available from discarded automobile
tires that might have potential in producing materials for use in blacktop
dressing manufacture. Our laboratory studies under this grant have shown that it is
possible to blend finely ground tire rubber into asphalt or coal tar by either of two
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processes. The resulting blends have been satisfactorily emulsified to form
materials suitable for use as blacktop dressings. Nine different blends con-
taining from 5 to 25 percent rubber have been made into emulsions and applied
to a blacktop surface in a high-traffic area (1800 cars/day)*
Evaluation of the outdoor exposures after one year shows good performance
for all samples.
Accelerated exposures in the Weather-Ometer indicate differences
exist, with some samples showing better performance than the controls containing
no rubber.
Slip-resistance test indicate a slight superiority for the rubber-
containing samples, both wet and dry.
Formulas for the nine experimental products appear in the Appendix.
BACKGROUND
Approximately 250 million new automobile tires are manufactured
every year. The ultimate destination of a large portion of these tires is the
trash heap, where they pose a major disposal problem. Disposal by burning
contributes to air pollution. Tires produce unstable landfill, and, hence,
are frequently banned from this method of disposal.
A sizeable number of tires are retreaded and reused. The percentage
of truck and bus tires that are retreaded is considerably higher than that
for passenger car tires. However, the number of retreaded tires is of little
consequence, since the retreading process only delays the discard date, and
the retreaded tire still ends up as a solid waste disposal problem.
A considerable tonnage of rubber polymer is "reclaimed". The re-
claiming process involves the separation of fabric and steel wire bead from
the rubber polymer, followed by digestion or depolymerization, and blending with
reclaiming oils. This results in a product that can be used for recycling back
into tire manufacture, tire retreading, and many noncritical materials, such
as elastic webbing, floor mats, sink mats, rubber hose, etc.
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Present use of tires for the reclaiming industry accounts for about
20 percent of the tires produced (about 50 million tires per year). Major
inputs to this industry are rubber factory scrap, tire buffings, and inner
tubes. Economic trends indicate a decreasing market for reclaimed rubber,
because several grades of virgin rubber are now selling for less than re-
claimed rubber. This is especially true if one considers that reclaimed
rubber is usually only about 50 percent rubber polymer, the remainder being
reclaiming oils.
Considerable interest over the years has been centered on "rubberized
roads". The technical literature is full of papers describing the use of rubber
with asphalt in the construction of highways. These papers are presently limited to
two modes of usage. The most prevalent use is the blending of chopped-up tires
with asphalt for use as a paving composition. The chopped tires replace a large
portion, or all of the aggregate (crushed rock or gravel) in the paving composi-
tion. Several state highway departments are known to be exploring this appli-
cation. Advantages claimed for rubberized roads prepared by this technique
include decreased skidding, longer road life, and decreased cracking and spalling
of the surface.
The second mode of rubberizing roads described in the literature in-
volves the addition of rubber latex (unvulcanized) to the hot-mix asphalt paving
composition. The same advantages are claimed as for the above procedure. How-
ever, it must be pointed out that this procedure is more costly than using
reclaimed rubber, and the unvulcanized rubber tends to contribute less to the
durability than does vulcanized rubber.
Several valuable bibliographies on the use of rubber in roads have
been prepared. One particularly valuable list of references, which is kept
up to date, is available from
Highway Research Board Library
National Academy of Sciences
2101 Constitution Avenue
Washington, D.C. 20418
Attention D. Bright, Librarian.
A review of these available bibliographies plus a literature search
by Battelle personnel prior to this study has failed to disclose a single reference
to the emulsification of a dispersion of vulcanized rubber in either asphalt or
coal tar, for use as a blacktop dressing for coating driveways, parking lots,
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etc. The closest approach found was the use of an emulsified rubber-asphalt
system as a bond coat between concrete and hot-mix asphalt road surfacing, to
decrease "reflective cracking".
INDUSTRY SURVEY
The study covered by this report was initiated by a survey of the
rubber reclaiming industry to identify materials that could be incorporated
into this program. Valuable telephone and mail communications with Midwest
Rubber Reclaiming Company, E. St. Louis, Illinois; U. S. Rubber Reclaiming
Company, Vicksburg, Mississippi; and Uniroyal, Naugatuck, Connecticut, were
especially helpful in the early phases. The Asphalt Institute, College Park,
Maryland, furnished excellent background information.
The Rubber Reclaimers Association, Naugatuck, Connecticut, was most
helpful. Through the cooperation of Mr. Tom Fitzgerald, Executive Secretary, it
was possible to arrange for the Association to supply six samples of reclaimed
rubber for use in this study. Inese samples were selected to be representative ot
the entire industry. They were prepared by Mr. C. E. Stuecheli of Xylos Rubber Com-
pany, Akron, Ohio. (This company is no longer in existence.) Mr. Louis Baker, Presi-
dent of A. Baker Manufacturing Company, has also been most helpful in supplying
samples of low-cost ground tires, as well as depolymerized rubber.
Mr. C. A. Hauck of Union Carbide Corporation, Tarrytown, New York,
has been helpful in supplying freeze-ground tire samples.
Mr. Charles McDonald of the City of Phoenix, Arizona, has graciously
supplied samples of his high-temperature dispersion of rubber in asphalt for
our emulsification studies, as well as excellent instructions for carrying out
his process.
Dr. E. E. McSweeney of Union Camp Corporation, Savannah, Georgia,
supplied samples on high and low penetration tall oil pitch which were also
used in this study.
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DESCRIPTION OF SAMPLES
Rubber Reclaimers Association Samples
As mentioned above, through the courtesy of Mr. Tom Fitzgerald,
Executive Secretary of the Rubber Reclaimers Association, arrangements were
made to obtain six samples of reclaimed rubber, representative of materials
that could be made by any reclaimer. Three compositions were to be made
available in both "slab" and "crumb" form. These three compositions (six
samples) were prepared by Mr. C. E. Stuecheli, of Xylos Rubber Company, Akron,
Ohio, 44301. (This company is no longer doing business.)
Properties of the six samples, as furnished by Mr. Stuecheli, (slab
and crumb form) are recorded as follows:
Sample No.
Ix (Slab & Crumb) 2x (Slab & Crumb) 3x (Slab & Crumb)
Scrap (35 mesh)
Defiberized 1UU 1UO 10°
Oil Crowley^ 8 8 12
Chem. Softener ill
Pitt-Consol 500 ± 1
Talc 555
Microcel E 222
(in crumb only)
Cooking Time @ 375 F (hrs) 6 10 6
Sp.G. 1.175 1.175 1.170
Mooney ML/4
(on refined scrap) M M OU
Ash % 8.9 8.9 8.8
Acetone Extract 21.5 21.0 24.8
Chloroform Extract 7.8 7.2 7.6
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Sample No.
Ix (Slab & Crumb)
26.1
40
2x (Slab & Crumb)
27.3
40
3x (Slab & Crumb)
26.4
37
Carbon Blac
Approx.
(a) Rubber reclaiming oil.
(b) Rubber hydrocarbon content.
No specific price quotations were given for the above samples. The
general understanding was that the price would be in the neighborhood of 9 to
14 cents per pound, depending on the volume demand, the cooking (processing) time,
and whether the product was desired in the "crumb" or "slab" form. Processing of
the samples into the "slab" form represents an additional step in the manufac-
turing, and,.-hence, increases the cost per pound.
Union Carbide Sample
Mr. C. A. Hauck of the Linde Division, Union Carbide Corporation,
Tarrytown, New York, 10591, supplied a sample of cryogenically ground whole
passenger tires. This sample had the following particle size distribution:
Nominal wt,
U.S. Mesh Size percent past
-100 100%
-200 50%
-325 5%
It was prepared from whole passenger car tires (tread plus sidewalls).
It contained no oils or other reclaiming agents. It was estimated that at least
90% of the fiber had been removed by the preparation process used. The projected
price was calculated to be 4 to 10 cents per pound, probably nearer the 4-cent
range. Union Carbide's code for this sample is UCC-B-WT-1.
Baker Samples
The A. Baker Manufacturing Company, South Bend, Indiana, supplied
three samples of ground passenger car tires for our studies. One of these
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samples was considered to be unsatisfactory for our use, based on its particle
size. The particles in this sample were roughly 1/2 inch x 1/2 inch. The two
remaining samples proved to be worthy of investigation. One sample was ground
whole passenger car tires with an estimated 75% of the fabric removed after
grinding. The particle size was similar to that of the Union Carbide sample.
A sieve analysis furnished by the supplier indicated it to be -12, +16 mesh.
The price of this material is expected to be in the 4 to 5 cents per pound area,
which might be reduced for large volume uses.
The third sample was labelled as "depolymerized" rubber. This sample
had been cooked and blended with reclaiming oils and surfactants. The exact
composition is considered to be proprietary. However, the reclaiming oils are
suspected to contain significant amounts of terpenes, disulfides, and highly
polar swelling agents added to improve the handling properties of the rubber.
The particle-size range of the sample appeared to be about the same
as that of the finely ground sample, approximately -12, +16 mesh. The presence
of fabric was not nearly as apparent as it was in the ground rubber.
The depolymerization requires extra processing. The price is, there-
fore, in the 7 to 8 cent per pound range. If we assume this sample to be 75%
rubber polymer and 25% reclaiming oils, the price is about 10 cents per pound
of rubber polymer, which is considered to be high for the intended application.
Phoenix Sample
Mr. C. H. McDonald, Engineering Supervisor, City of Phoenix, Arizona,
85034, supplied a sample of rubber that had been incorporated into asphalt by
a heating process developed by him for use in patching and pavement repair
compounds. This sample was a 25% dispersion of ground tire rubber (-16, +25
mesh) in 120-150 penetration grade Los Angeles Basin asphalt.
The incorporation process involves heating the mix until a reaction
occurs, yielding a jelly-like composition. A patent application has been filed
by McDonald covering the process.
Mr. McDonald has not tried to emulsify the material. Its use has been
restricted to paving and pavement patching using the hot-mix technique, and
a hot-melt spray coating for streets.
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Care must be used not to overheat the sample, since depolymerization
of the rubber takes place at about 400 F, which injures the durability of the
product, according to Mr. McDonald.
Uniroyal Dispersion
Uniroyal Chemical, Naugatuck, Connecticut, 06770, markets a water
dispersion of reclaimed rubber. This dispersion is 58% solids, and is anionic
in nature. The solids content of the dispersion was
Component Parts
Ground Whole Passenger Tires 100
Tall Oil Pitch 4
Bituminous Petroleum 3
Asphaltic Resin 5
Oleic Acid 9
The price, in large quantity, can be expected to be about 20 cents
per dry pound.
The sample appeared to be of medium viscosity. Suspended particles
appeared large, much larger than in an emulsion.
Although this sample was anionic in nature, it was found to be incom-
patible with separately prepared emulsions of either asphalt or coal tar made
by normal procedures.
Based on the high price and the difficulty of incorporating it in
blends with asphalt or coal tar, this sample was judged to be unsuitable for
this study.
Porter Sample
The sample received from 11. K. Porter Company was chopped rubber hose,
in the form of rings. It contained considerable fabric. The particles were too
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large to disperse readily into either asphalt or coal tar. The sample was,
therefore, judged not suitable for use in this study.
Tall Oil Pitch
The Union Camp Corporation, Savannah, Georgia, 31402, furnished two
representative samples of tall oil pitch, high and low penetration. The analyses
of these samples were as follows
High Penetration Low Penetration
Acid Number 64 31
Saponificatlon Number 109 97
Rosin Acids % 28.2 15.1
Fatty Acids % 39.7 48.1
Unsaponifiables 32.1 36.8
The presence of rosin acids, fatty acids and terpenes in tall oil
pitch make it appear interesting as a dispersing agent for vulcanized rubber.
Asphalt Emulsion Base
The asphalt used as the base in this study is a petroleum residue
asphalt with a penetration of 190. It was obtained from Ashland Chemical
Company as representing their recommendation for water emulsion use.
Coal Tar
The coal-tar base used in this study was obtained from Reilly Tar &
Chemical Corporation. It is a standard emulsion-type base, sold by the supplier
to many blacktop-dressing manufacturers.
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EXPERIMENTAL
Incorporation of Rubber into
Asphalt and Coal Tar
Several methods were investigated to incorporate the various types
of rubber received into asphalt and coal tar. The first and one of the most
promising methods was to place the asphalt or coal tar into a jacketed Bramley
mill and add the rubber during agitation. The best technique was to heat the
mill, after addition of the asphalt or coal tar, to 265 to 275 F with 45 to 50 psig
pound steam. When the asphalt or coal tar was liquid, the rubber was added.
After sixty minutes, the steam was turned off and cold water at 40 to 45 F was
circulated through the jacket for an additional sixty minutes. This cycle
was repeated four times. The Bramley mill is a modified sigma-blade mixer which
places high shear and tearing action on thick mastic materials. This action
which occurred during the cold-water segment of the cycle tore apart the rubber
particles which had been swollen due to the heat of the first half of the cycle
and the solvency of the oils in the asphalt and/or coal tar.
The second method tried for incorporating rubber into asphalt and
coal tar was to use a 6-inch rubber mill. This method resulted in a higher
percentage of rubber being incorporated into the asphalt and the coal tar, but
it was a much more expensive process than any of the other methods explored.
The rubber was milled on heated rolls until it was in sheet form. Then a
small amount of asphalt or coal tar was added. The greatest reduction of the
rubber that could be obtained was a composition containing 25% asphalt and
75% rubber. This mixture was very difficult to remove from the mill even
when the rolls were cooled to 50 F. Further reduction of the rubber con-
tent was made by heating the rubber-asphalt mixture until liquid, then
adding more liquid asphalt until a 5% rubber-asphalt mixture was obtained.
There did not appear to be any major differences in properties of the rubber-
asphalt and rubber-coal tar blends made by this method and the first method
using the Bramley mill; therefore, due to economics, this method was not in-
vestigated further.
The third method investigated was to swell the rubber in tall oil
before the addition of asphalt or coal tar. This work was done in the Bramley
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11
mill using the same cycles as described in the first method. By swelling the
rubber in the tall oil before adding the asphalt or coal tar, the final mix-
tures had smoother texture and the rubber appeared to be better incorporated
into the asphalt and coal tar; however, the high oil content made these mix-
tures very difficult to emulsify.
The fourth method used to incorporate the rubber was the Phoenix
method. This process method was developed by Mr. Charles H. McDonald,
Engineering Supervisor, Engineering Department, Materials Testing Station,
City of Phoenix, Arizona, 85034. This process was to heat the asphalt to 350 F
and add 25 % ground rubber (-16 mesh, +25 mesh) to the heated asphalt during
agitation. Mr. McDonald emphasized that the mixture should not be heated over
400 F or the rubber would depolymerize. Mr. McDonald stated that the rubber
reacted with the asphalt to form a jelly-like composition. A patent has been
applied for by Mr. McDonald. Our experiments showed that the 350 F temperature
was fine for incorporation of rubber into asphalt but slightly higher temperatures
(375 to 380 F) were needed to get the rubber into coal tar.
It was decided, based on economics, ease of incorporation, and appearance
of the mixtures of rubber-asphalt and rubber-coal tar, to use the methods desig-
nated one and four. The following table lists the name of the rubber used,
percentages of rubber added, method of incorporation, and the base material
(asphalt or coal tar) to which the rubber was added.
TABLE 1. -INCORPORATION OF RUBBER INTO
ASPHALT AND COAL TAR
Rubber Sample
(Name) Rubber Type
% Added Method
(a)
Base Material
Baker
Baker
Xylos Ix
Xylos 2x
Fine ground
tires w/fibers
Full reclaim
Full reclaim
Full reclaim
5 + 25
5+25
5 + 25
5 + 25
1 + 4
1 + 4
1 + 4
1 + 4
Asphalt & Coal tar
Asphalt & Coal tar
Asphalt & Coal tar
Asphalt & Coal tar
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TABLE 1. (Continued)
Rubber Sample
(Name) Rubber Type
% Added Method
(a)
Base Material
Xylos 3x
Full reclaim
5+25 1+4 Asphalt & Coal tar
Union Carbide Cryogenic Ground
90% Fibers removed 5+25 1+4 Asphalt & Coal tar
(a) 1 - Battelle method (Bramley mill)
4 - Phoenix method.
The Baker fine ground rubber with fiber was incorporated into asphalt
and coal tar with no difficulties by both the Battelle and Phoenix methods at
both the 5 and 25 percent level.
The Baker full reclaim rubber was extremely difficult to incorporate
by the Phoenix method when added to either .the hot asphalt or hot coal tar at
both the 5 and 25 percent level; the rubber would cause heavy foaming and in
most cases foamed out over the container. This reaction was most likely caused
by boiling of the oils used to reclaim the rubber.
Also the Baker reclaimed rubber was fairly difficult to incorporate
into asphalt and coal tar at the 5 percent level in the Bramley mill and the
resulting mixture was granular in appearance. At the 25 percent level the Baker
reclaimed rubber had lumps about 1/4 inch in diameter.
Xylos Ix crumb was the only one of the three reclaimed rubbers from
Xy]os Rubber Company that could be incorporated smoothly into the asphalt and
coal tar in the Bramley at both the 5 and 25 percent level. The other two
rubbers, Xylos 2x and Xylos 3x, looked similar to the 5 percent Baker reclaim.
They all had a very granular texture. All the Xylos crumb rubbers were incor-
porated into asphalt and coal tar by the Phoenix method and looked good at both
levels of addition (5 and 25 percent).
The Union Carbide cryogenic ground rubber was easy to incorporate
into both asphalt and coal tar by both methods at the 5 and 25 percent levels.
All three slab rubber samples proved to be very difficult to disperse
in both asphalt and coal tar, and their use was abandoned.
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13
Emulsification of Rubberized Asphalt
All asphalt emuIsification work was conducted with an Asphalt Emulsion
Base obtained from Ashland Chemical Company. During the first attempts to emulsify
the asphalt, various clays and talcs were used as fillers and Indulin W-l was
used as an emulsifying agent. Most of these emulsions were very poor and heavy
settling occurred when the emulsions stood overnight. The most stable emulsions
resulted when Mistron ZCS talc was used as the filler. The following was selected
as the standard method for evaluating rubberized asphalt.
Three hundred grams of water and 100 grams of United Sierra's Mistron
ZCS talc were placed in a quart container. A Premier mill mixer was used to
provide high-speed agitation ("\-5000 rpm) of the water-talc slurry. The slurry
was heated to 160 to 170 F during constant agitation. Two grams of calcium
chloride and 85 to 90 grams of hot (180 to 200 F) asphalt-rubber mixture were
added. As soon as the addition of asphalt-rubber mixture was made, the agitation
was increased to 7500 to 8000 rpm for one minute. Table 2 lists the asphalt-
rubber mixtures emulsified and comments on their stability and appearance.
TABLE 2. EMULSIFIED ASPHALT-RUBBER MIXTURES
Asphalt-Rubber
Xylos Ix
Xylos Ix
Xylos Ix
Xylos Ix
Union Carbide
Union Carbide
Union Carbide
Union Carbide
Baker Reclaim
% Rubber
5
25
5
25
5
5
25
25
5
Method (a)
BCL
Phoenix
Phoenix
BCL
Phoenix
BCL
Phoenix
BCL
BCL
Comments
Appearance
Very Good, Smooth
Good, Smooth
Good, Smooth
Good, Slightly Granular
Excellent, Very Smooth
Excellent, Smooth
Good, Smooth
Good, Smooth
Good, Slightly Granular
Stability
Good
Good
Good
Good
Very Good
Very Good
Good
Good
Fair
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14
TABLE 2. (Continued)
'Asphalt-Rubber %
Baker Reclaim
Baker Reclaim
Baker Reclaim
Baker Ground
Baker Ground
Baker Ground
Baker Ground
Phoenix- Asphalt
Rubber Mix
Xylos 2x
Xylos 2x
Xylos 3x
Xylos 3x
(a) BCL - Battelle1
Rubber
5
25
25
5
25
5
25
25
5
5
5
5
s Columbus
Method (a)
Phoenix
Phoenix
BCL
BCL
Phoenix
Phoenix
BCL
Phoenix
Phoenix
BCL
Phoenix
BCL
Comments
Appearance
Good, Slightly Granular
Fair, Lumpy
Fair, Granular
Very good, Very Smooth
Good, Smooth
Good, Smooth
Good, Very Slightly
Granular
Fair, Lumpy
Good, Slightly Granular
Fair, Granular
Fair, Granular
Fair, Granular
Stability
Good
Fair
Good
Good
Good
Good
Good
Fair
Fair
Fair
Fair
Fair
Laboratories .
Rubberized Coal Tar
Emulsif ication
All coal tar emulsification work was conducted with a coal tar emul-
sion base from Reilly Tar and Chemical Company. Initial work on eraulsification
was to evaluate several different clays and emulsifiers. The following list
gives the clays and emulsifiers tried.
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15
Clays
Hydrite PXS
Kaogen A3
Hydrite RS
Kaophobe 45
#20 Clay
Hydrite Flat "D"
Supplier
Georgia Kaolin Co.
Burgess Figment Co.
Georgia Kaolin Co.
Emulsifiers
Kricinol 35
Indulin C
Indulin W-l
Westvaco M-50
Westvaco Resin 90
Arizona DRS 42
Arizona DRS 43
Dresinate X
Dresinate XX
Redicote E-l
Redicote E-3
Redicote E-5
Redicote E-9
Redicote E-ll
Redicote E-12
Redicote E-14
Redicote E-23
Redicote E-27
Redicote i:-28
Supplier
Arthur C. Trash Co.
Westvaco Corp. Chem. Div.
Arizona Chemical Co.
Hercules, Inc.
Armour Industrial Chemicals
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16
The following was selected as the standard method for the evaluation
of rubberized coal tar. One hundred and twenty grams of water, 20 grams of Burgess #20
#20 clay, and 10 grains of Mistron ZCS Talc were placed in a quart container. A Premier
mill mixer was used to provide high-speed agitation (~5000 rpm) of the water-clay-
talc slurry. The slurry was heated to 160-180 F with constant agitation.
When the slurry reached the desired temperature, 1 gram of Indulin W-l and
1 gram of calcium chloride was added slowly to the slurry during constant
agitation.
When approximately 50 percent of the rubberized coal tar had been
added the mixer speed was increased to 7500-8000 rpm. After all the rubberized
coal tar was added, 1 gram of potassium ricinoleate was added. Before the
addition of the potassium ricinoleate the rubberized coal tar was suspended
in little globules in the slurry. The addition of the potassium ricinoleate
caused the breaking up of the globules and resulted in a good emulsion.
Table 3 lists the coal-tar rubber mixtures emulsified and comments on their
stability and appearance.
TABLE 3. EMULSIFIED COAL-TAR RUBBER MIXTURES
Coal- Tar Rubber
Xylos
Xylos
Xylos
Xylos
Union
Union
Union
Baker
Baker
Ix
Ix
Ix
Ix
Carbide
Carbide
Carbide
Reclaim
Reclaim
% Rubber
5
25
5
25
25
5
5
5
5
Method
BCL
Phoenix
Phoenix
BCL
Phoenix
Phoenix
BCL
Phoenix
BCL
Good,
Good,
Good,
Good,
Good,
Good,
Good,
Fair,
Good,
Comments
Appearance
smooth
slightly granular
very slightly granular
slightly granular
smooth
smooth
smooth
granular
granular
Stability
good
good
good
good
good
good
good
fair
good
-------
17
TABLE 3. (Continued)
Coal-Tar Rubber
Baker Ground
Baker Ground
Baker Ground
Baker Ground
Xylos 2x
Xylos 2x
Xylos 3x
Xylos 3x
% Rubber Method
25
5
5
25
5
5
5
5
Phoenix
Phoenix
BCL
BCL
Phoenix
BCL
BCL
Phoenix
Comments
Appearance
Good, very slightly granular
Good, smooth
good, smooth
good, very slightly granular
Fair, granular
Fair, granular
Poor
Fair, granular
Stability
good
good
good
good
fair
fair
poor
fair
Preparation of Experimental Emulsions
for Exterior Evaluations
Asphalt
Five experimental asphalt-rubber emulsions and four experimental
coal-tar rubber emulsions were prepared in 4-gallon lots for exterior exposure
evaluation. Table 4 designates the experimental emulsions made.
TABLE 4. EXPERIMENTAL EMULSIONS
FOR EXTERIOR EXPOSURE
Emulsion
Number
TE-1
TE-2
Rubber
Xylos Ix
Baker Fine
% Rubber
5
5
Method (a)
Rubber Incorporation
BCL
BCL
Base Material
Asphalt
Asphalt
-------
18
TABLE 4. (Continued)
Emulsion
Number
TE-3
TE-4
TE-5
TE-6
TE-7
TE-8
TE-9
Rubber
Union Carbide
Baker Fine
Baker Fine
Xylos Ix
Union Carbide
Union Carbide
Baker Fine
% Rubber
5
25
5
5
5
25
5
Method *a*
Rubber Incorporation
BCL
Phoenix
Phoenix
BCL
BCL
Phoenix
BCL
Base Material
Asphalt
Asphalt
Asphalt
Coal tar
Coal tar
Coal tar
Coal tar
(a) BCL - Battelle's Columbus Laboratories.
All the emulsions were made on a laboratory model Cowles Dissolver.
The asphalt control and five experimental emulsions were formulated as follows.
Added to Dissolver tank
9 kilograms water
3 kilograms Mistron ZSG talc
60 grams Calcium Chloride
Heated to 160 F with constant agitation then added 4.5 kilograms
asphalt or asphalt-rubber mix heated to 200 to 210 F during constant agitation.
Coal Tar
follows.
The four experimental coal-tar rubber emulsions were formulated as
Added to Dissolver tank
7.2 kilograms water
1.2 kilograms Burgess it20 Clay
.6 kilograms Mistron ZSC talc
60 grams Indulln W-l
60 grams Calcium Chloride
-------
19
Heated above to 180 F with constant agitation then added 5.4 kilograms
coal tar-rubber mix.
Heated to 220 to 230 F during constant agitation. Immediately after
all the coal tar-rubber mixture was added, 60 grams of potassium ricinoleate
was added.
All the experimental emulsions were smooth and looked good. After
standing for 14 days, TE-4 had a granular appearance and it was fairly difficult
to reincorporate the surface liquid. TE-8 was extremely difficult to stir;
however, after the surface liquid was reincorporated, it had a very smooth
texture. All of the other experimental emulsions mixed as well as the coal tar
and asphalt controls.
Weather-0-Meter Studies
Table 5 lists the emulsions that were applied to 2-1/2-inch x 6-inch as-
bestos boards for evaluation in the Weather-0-Meter. The twin-arc Weather-0-Meter
was cycled so that the panels would have 108 minutes dry, high temperature
(100 to 120 F) and 12 minutes of water spray directly on the panels.
Evaluation of the Weather-0-Meter exposed samples is given in Table
5.
Weather-0-Meter Evaluations
It was noted early in the exposure life of the panels in the
Weather-0-Meter, that atypical behavior was being encountered. The changes
observed did not agree with the noted performance of the samples applied to
Battelle's driveway. Failure by forming large alligator-skin-like cracks was
almost universal.
This variance in performance is felt to be due to the facts that
(1) The samples in the Weather-0-meter series are much
thicker (1/8 inch) than the driveway samples.
-------
TABLE 5. WEATHER-0-METER EVALUATION
OF EXPERIMENTAL EMULSIONS
Specimen Emulsion
Number Number Comp Components
Method of Rubber
Rubber Incorporation^)
100 hr Evalua-
tion Comments
1000 hr Evaluation
Comments
1, 2 TE-1 Asphalt-Xylos Ix
3, 4 TE-2 Asphalt-Baker fine
5, 6 TE-3 Asphalt-Union Carbide
7, 8 TE-4 Asphalt-Baker fine
9, 10 TE-5 Asphalt-Baker fine
11, 12 TE-6 Coal tar-Xylos Ix
13, 14 TE-7 Coal tar-Union Carbide
25
BCL
BCL
BCL
Phoenix
Phoenix
BCL
BCL
Very slightly
checked smooth
film
Slightly checked
soft film, few
rubber chunks
Medium checking
mud cracking,
dull film, soft,
rubbery
Very rough rub-
bery, heavy
cracks
Smooth film, gray
rubber chunks
Thin, heavy alli-
gatoring medium-
hard film
Very heavy alli-
gatoring, flat
film, medium
hard film
Smooth, very
slightly checked
gray
Slightly checked
whitish, few
rubber chunks
Considerable check-
ing, whitish
eroded
ro
o
Rough, slight
cracks, rubbery
Smooth, gray, very
slighly checked
Dull, heavily alii-
gatored, pinholed
Dull, very heavily
alligatored, pin-
holed
15, 16
TE-8
Coal tar-Union Carbide
25
Phoenix
Gray, hard, no
cracks, few
craters
Slight surface
cracks, whitish
pinholed
-------
TABLE 5. (Continued)
Specimen
Number
Emulsion
Number
Components
Components
% Rubber Method of Rubber 100 hr Evalua-
°L Rubber Incorporation^) tion comments
1000 hr Evaluation
Comments
17, 18
TE-9
Coal tar-Baker fine
BCL
21, 22
23, 24
27, 28
29, 30
CTC
AC
Coal tar-Control
Coal tar-Baker fine 25
Coal tar-Union Carbide
Asphalt-Union Carbide 25
Commercial
Phoenix
Phoenix
Phoenix
Heavy coating
very, very heavy
alligatoring
healed, soft
rubbery
Very smooth, high
gloss, black
medium soft
Slightly gray
very rough,
rough chunks
Black, smooth
hard, flat
Medium cracking
slightly gray
soft, rubbery
thin film
Extremely alli-
gator, pubby blis-
ters
Bronzed flat, pin-
holed thin
Very rough, no
checks, no pin-
holes
Black, Smooth,
few pinholes
Considerable check-
ing, gray, thin-
eroded
-------
22
(2) The Weather-0-Meter samples are applied to Transite®
board (asbestos-cement composition) rather than blacktop.
(3) The Weather-0-Meter samples are subject to sudden tempera-
ture changes of wider excursion than the driveway samples.
(4) The Weather-0-Meter samples are not subject to the pres-
sure of traffic, which can cause a healing of small
cracks to occur.
Even though the Weather-0-Meter exposures were exhibiting atypical
failures, they were continued on exposure to obtain valuable comparative data.
After only 100 hours of exposure, it became apparent that cracking of
coal-tar-rubber blends was related to the amount of rubber in the blend. Cracking
was restricted to the coal tar samples containing only 5 percent rubber. Those
samples containing 25 percent rubber did not crack. Although no cracking has been
observed in any samples exposed in the Battelle driveway, the results indicate
that a higher amount of rubber than 5 percent might be desirable in coal tar
compositions, in order to obtain maximum flexibility.
The differences observed early in the exposure period continued through-
out the exposure life.
Slip Resistance of Experimental Emulsions
The experiment emulsions were brushed onto a damp piece of 1/8-inch asbestos
board. Three specimens were evaluated for each experimental emulsion and a con-
trol. The slip resistance was measured in wet and dry conditions. The test pro-
cedure was to apply a piece of tread from a rubber tire to the coated surface and
to place a 500-gram weight on the rubber tread. A Chatillon measuring device
was used to determine the pull in pounds necessary to move the weighted rubber
tread from at rest to a sliding position. The rubber tread had an area of 1.68
square inches. The measuring device is calibrated in 0.05-lb increments and is
Model No. DPP-5. Table VI lists the specimens and the pull in pounds necessary
to break friction hold, wet and dry. The figure given represents an average
of three readings per specimen and the average of the three specimens evaluated.
-------
23
TABLE 6. SLIP RESISTANCE OF
EXPERIMENTAL EMULSIONS
Specimen No.
TE-1
TE-2
TE-3
TE-A
TE-5
TE-6
TE-7
TE-8
TE-9
TE-10
TE-11
Description
5% Xylos Ix-Asphalt
5% Baker fine-Asphalt
5% Union Carbide-Asphalt
25 % Baker fine-Asphalt
5% Baker fine-Asphalt
5% Xylos Ix-Coal tar
5% Union Carbide Coal tar
25% Union Carbide Coal tar
5% Baker fine Coal tar
Asphalt Control
Coal tar Control
Average pull, Ib
Dry Wet
1.27 1.19
1.49 1.40
1.83 1.27
Unable to evaluate
because of large
chunks of rubber
on surface of coating
1.61 1.49
1.07 0.96
1.09 1.05
1.05 0.99
1.04 1.04
1.43 1.56
0.99 0.91
All of the experimental coal tar-rubber emulsions have improved slip
resistant both wet and dry when compared to the commercial control. The same
is true with the experimental asphalt-rubber emulsions with one exception.
The asphalt emulsions all show greater skid resistance than the coal tar
emulsions. This effect is mostly likely due to the slightly softer films of
asphalt.
-------
24
Application of Nine Experimental
and Two Control Emulsions
The nine experimental and two control emulsions were applied on an
evaluation site in the north drive of Battelle's Columbus Laboratories' entrance
to the parking area. (See Figure 1.)
Most of the experimental emulsions were applied with no difficulty.
Emulsion TE-4, Baker fine rubber at 25 percent level, was fairly hard to apply
in a smooth coating because the rubber particles had swollen and agglomerated
during standing in the container. Emulsion TE-8 was very difficult to apply
because of a very rapid break time. Several of the experimental emulsions were
gray when dried, indicating that too much extender material (talc and clay) was
used in the formulation.
The emulsions were applied on Saturday, May 20, 1972, between 1:00 p.m.
and 4:00 p.m. The temperature was between 80 and 85 F during the time of appli-
cation. Figure 2 shows the evaluation site after application of the experimental
and control emulsions. It is estimated that a minimum of 1800 cars pass over
the experimental emulsions every weekday.
Three-Week Evaluation of the
Applied Experimental Emulsions
The experimental emulsions and the two controls were given brief
observations three weeks after their application. It is estimated that ap-
proximately 28,000 cars had passed over the experimental emulsions in this
time period. Table 7 lists the emulsions and observations made.
TABLE 7. THREE-WEEK EVALUATION OF
EXPERIMENT AND CONTROL EMULSIONS
Emulsion Observations
TE-1 Very good crack sealing
Asphalt Not very soft
5% Xylos Ix Slightly streaky application
TE-2 Grayish-white at edges
Asphalt Black in traffic areas
5% Thick spots very soft
Streaky application
-------
FIGURE 1. EVALUATION SITE BEFORE APPLICATION
FIGURE 2. EVALUATION SITE AFTER APPLICATION
-------
27
TABLE 7. (Continued)
Emulsion
Observations
TE-3
Asphalt
5% Union Carbide
TE-4
Asphalt
25% Baker
TE-5
Asphlat
57. Baker
TE-6
Coal tar
5% Xylos Ix
TE-7
Coal tar
5% Union Carbide
TE_8
Coal tar
257. Union Carbide
TE-9
Coal tar
Asphalt Control
Coal tar Control
Tire abrasion marks
Gray
Thick areas soft
Fair crack sealing
Slightly streaked from application
Grayish-white
Very granular, rubbery, sticky
Very streaky, Rubber appears to be
separating
Gray
Tire abrasion marks
Fairly tough
Uniform appearancy
Very slightly granular
Very dark gray
Thick areas slightly soft
Cracks not very well sealed oil
oil drippage resulted in soft spots
Black
Very good general appearance
Thick areas soft
Cracks appear well sealed
Considerable tire abrasion marks
Harder than TE-7
Considerably grayer than control
Oil drippings not soft
White in nontravelled areas
Very thick spots are soft
Few tire abrasion marks
Dark gray-darker than asphalt
control
Puddled
Soft in deep areas
Tire abrasion marks
Slight gray general appearance
Very uniform
Fair cracking filling
Fairly hard in thick area
-------
28
The observations made on the control and experimental emulsion after
three weeks were very general and the differences were slight. No major trends
were detected at that time.
Subsequent Evaluations
Periodic observations of the conditions of the applied stripes were
made throughout the period from May 20, 1972, through May 20, 1973.
On July 28, 1972, observations indicated that all samples were showing
wear on the tops of aggregate particles, including both controls. All samples
continued to exhibit good sealing between aggregate particles. No major differences
were noted between samples. Those samples appearing white or light gray shortly
after application appeared to be darkening, so that very little difference (if any)
could be seen between exposed samples.
Examination again in late December, 1972, showed some differences be-
ginning to appear. However, they were decided to be not definitive enough to
permit identification of any trends. Those samples containing 25 percent rubber,
based on the bitumen content, appeared to be losing some of the granules of rubber
by its working out of the surface, particularly in the high-traffic areas.
It also appeared at this time that the finer ground (cryogenic) rubber
produces a more penetrating dressing that appeared to seal cracks better than those
dressings made from coarser rubber particles.
Examination of the test patches was again made on March 20, 1973. In
general, the winter of 1972-73 had been moderate, with only a small amount of snow-
fall in Columbus, Ohio. These conditions did, however, result in an unusual
amount of freezing and thawing. In spite of this, all coatings including the con-
trols appeared to have lasted through the winger remarkably well. Although the
tops of the aggregate particles were worn clean of the dressing material, all
coated areas, regardless of the coating material, were still well sealed between
the aggregate particles, providing water-tightness. The conclusion was reached
that all experimental samples were at least as good as the controls. Indications
continued to be present that the 5 percent rubber was giving superior performance
to the 25 percent rubber samples, and that the finer-ground rubber had apparently
penetrated further into the pores and cracks of the substrate.
-------
29
A final examination was made on May 22, 1973, after the applications had
been on exposure for one full year. During that year, a conservative estimate
indicated more than 450,000 vehicles had passed over the center portions of the
applications. Although most of these vehicles were passenger cars, a significant
number were trucks, many of them of the heavy, tractor-trailer type. The area
also included a portion of each application exposed to parking, including oil
drippage (on the south edge).
Prior to examination, the strips were hosed with cold water, and brushed
dry with a push-broom, to insure the removal of loose dirt. The strips were also
photographed when dry. These photographs are presented as Figures A-l to A-1L in
the Appendix of this report.
Observation of the general appearance of the exposed samples showed that
all materials were in fair conditions. Although the sealer had been worn off the
tops of aggregate particles, the area between particles remained filled, and the
surface appeared to be well sealed for all samples. Cracks in the pavements that
were present at the time of application either remained filled and sealed, or had
not enlarged from their conditions prior to sealing.
Intercomparing the samples, all experimental materials appeared to be in
at least as good condition as either of the two controls. The asphalt control
appeared slightly more worn than the coal tar control.
Sample TE-1 remained quite smooth. The large crack in the base pave-
ment remained fairly well sealed by the sealer. It had not enlarged from the pre-
application state. It was not injured in the parking area in the foreground of the
oil drippage.
Sample TE-2 showed some application marks due to thick areas. However,
it remained in very good condition, and appeared to still be giving good protection
and sealing.
Sample TE-3 appeared very uniform in application. It remained dark. No
damage could be seen due to oil drippage.
Sample TE-4 showed marked application marks due to thick areas. The
granular appearance that was evident just after application has, for the most part,
disappeared. Due fo its heavy nature, it did not penetrate the large crack very
deeply. However, tlic crack still appeared sealed for the most part, and had not
enlarged noticeably from its original size.
-------
30
Sample TE-5 still retained its original uniform appearance. It re-
mained dark, having lost most of the original gray appearance. Good protection
of the base asphalt seemed to be maintained.
Sample TE-6 shows some application marks. The large crack is incom-
pletely sealed, probably because of its large size. Generally good protection
is being maintained by the coating.
Sample TE-7 is, for the most part, quite uniform. A few application
marks can be seen in the foreground. Small cracks appear to be well sealed.
The light spots in the foreground are due to oil drippage from parked cars. No
injury to the coating was noted in these areas.
Sample TE-8 has lost its early whiteness and has now become dark gray.
Very few application marks can be seen. Excellent protection seems to be main-
tained. Small cracks remain well sealed.
Sample TE-9 remains gray in color. Some application marks are visible.
The large crack in the foreground remains well sealed. Generally good performance
was noted.
Sample CTC, the coal tar control, appears very thin. The large crack at
the left of the application was still well sealed. Show-through of the aggregate
was very noticeable.
Sample AC, the asphalt control, appears slightly worn in the center,
high traffic area. The large crack on the right remained well sealed.
CONCLUSIONS
Many conclusions are possible from the study as described in this report.
However, it appears that the following are among the most important.
(1) It has been demonstrated beyond doubt that it is
feasible to incorporate ground rubber from discarded
automobile tires in bitumens such as coal tar or
asphalt to prepare a product suitable for us<_ as a
blacktop dressing.
(2) The economics, although not completely resolved, seem
to be favorable since it appears possible to improve
the performance of asphalt to essential!) match that
of coal tar.
-------
31
(3) The economics will, of course, depend on the optimum
level of rubber in bitumen.
(4) The optimum level of rubber appears to lie somewhere
between 5 and 25 percent of the rubber-bitumen blend.
(5) The rubber may be incorporated into the bitumen by
several processes. Both the Battelle and the Phoenix
process used in this study appeared to give satisfactory
results.
(6) Satisfactory durability was observed for all experimental
samples exposed after one year of service.
(7) Assuming 10 percent rubber to be the optimum con-
centration, each gallon of emulsion would contain
approximately 1/2 pound of ground rubber. This
gallon would normally cover about 40 square feet
(optimistic estimate).
One passenger car tire, after removal of the bead and the major part
of the fabric, will yield approximately 10 pounds of ground rubber, or enough to
prepare 20 gallons of emulsion.
The average driveway is estimated to contain about 800 square feet
(8* x 100'), and should require about 20 gallons of dressing for good protection.
It, therefore, appears that about one tire per average driveway would
be used.
In addition, the millions of square feet of blacktop in shopping center
parking lots, city streets, airport loading aprons, taxi strips, etc, could furnish
enough area to use up all the roughly 200 million discarded passenger car tires
per year.
PATENTS
It is believed that the process for emulsification of a vulcanized
tire rubber-bitumen blend is new and novel. Before proposing the research pro-
gram covered by the subject grant, a fairly comprehensive literature study failed
-------
32
to uncover any reference to such an emulsification. The early phases of the
study included contacts with many asphalt, coal tar, and rubber specialists.
These contacts failed to reveal any emulsification of rubber-bitumen blends.
Although no patent novelty search has been made of the process, the
intelligence obtained from the above-noted sources substantiates that the emulsi-
fication of rubber-bitumen blends is a novel process, resulting in a new, useful
material that might be patentable.
After examining the many facets of this situation, the following course
of action is recommended.
(1) The first step should be a patent novelty search of
the process of preparing vulcanized rubber-bitumen
(asphalt or coal tar) blends, and emulsification of
such blends to prepare water-thinnable systems. This
step would permit a decision regarding the possible
patentability of the process, and the advisability of
preparing an application for a patent.
(2) The preparation of a strong patent application will
doubtless require some additional studies to establish
limits of composition and preferred formulas. It should
be remembered that the study covered by this report was
designed to demonstrate feasibility of the basic idea.
Neither tisie ncr funds were available to obtain the
comprehensive information and mutitude of examples,
required for a strong patent application. Since the
present contract has terminated, and no extension is being
anticipated, funds for supporting these additional studies
will need to be sought elsewhere.
(3) Assuming a patent application is made and a patent is
granted for the process or product, the rights thereto
would be governed by the patent provisions in the grant.
Since the fundamental purpose of this study is to stimulate widespread
interest in and use of this method of solving one difficult phase of the urgent
solid waste disposal problem, it is urged that any obtained patent become an
item of public domain, in order to encourage as widespread use of the process as
possible.
-------
33
A report of invention has been prepared and is being submitted to the
Grants Officer. This invention report covers the basic concept of blending
ground automobile tires with bitumens (asphalt or coal tar) and emulsifying the
resulting blends to form water-thinnable compositions suitable for use in treating
blacktop driveways, parking lots, highways, etc.
FUTURE WORK
An inspection of the exposure series was made with the Project Officer
of this study on May 24, 1973. At that time, it was mutually agreed between the
Project Officer and Battelle's Columbus Laboratories' personnel that the objective
of the present study had been reached. Complete feasibility of the basic idea
of bitumen-rubber blends that could be emulsified had been demonstrated. Therefore,
the objectives of the grant were judged to have been met, and no further work was
judged to be necessary.
However, the complete success of this study has opened up many in-
triguing possibilities.
First and foremost, it must be emphasized strongly that the materials
exposed in this study represent only starting point recipes. The limited program
did not permit (1) selection of the optimum raw materials used to make the emul-
sions, (2) establishment of optimum rubber-bitumen ratios, (3) identification of
best preparation techniques, or (4) conduct long-range storage stability tests.
All of these studies should be carried out before suitable assurance of a marketable
product can result.
In addition, the observed properties of rubber-bitumen blends point
towards many possibilities for other uses than blacktop dressings. These might
include
(1) Vehicle under-coats
(2) Coatings for underground protection of steel structures
(tanks, pipes, etc.)
(3) Roofing (composition and built-up)
(4) Marine paints
(5) Adhesives
(6) Acid-proofing (battery cases, etc.)
(7) Waterproofing
-------
(8) Expansion joints (concrete construction)
(9) Sound and vibration dampeners
(10 Sealants
(11) Caulking compounds
(12) Paper impregnants
(13) Ammunition case enamels
(14) Thermal insulation
Each of the above end-uses would require study to develop optimum
compositions.
Considerable interest in this program has been exhibited by both
government agencies and industrial organizations. The successful completion
of a study such as this can be expected to result in aiding the solution of a
solid waste disposal problem, and at the same time, development of a saleable
product of improved quality and favorable economics.
-------
APPENDIX
A-l
FORMULA TE-1
Water
Mistron ZCX talc
Calcium Chloride
Asphalt - 5% rubber mix
Asphalt - 4.275 kg
Xylos Ix - 0.225 kg
FORMULA TE-2
Water
Mistron ZCS talc
Calcium Chloride
Asphalt - 5% rubber mix
Asphalt - 4.275 kg
Baker Fine - 0.225 kg
9 kilograms
3 kilograms
60 grams
4.5 kilograms
9 kilograms
3 kilograms
60 grams
4.5 kilograms
FORMULA TE-3
Water
Mistron ZCS talc
Calcium Chloride
Asphalt - 5% rubber mix
Asphalt - 4.275 kg
Union Carbide - 0.225 kg
9 kilograms
3 kilograms
60 grams
4.5 kilograms
-------
A-2
FORMULA TE-4
Water
Mistron ZCS talc
Calcium Chloride
Asphalt - 25% rubber mix
Asphalt - 3.375 kg
Baker Fine - 1.125 kg
FORMULA TE-5
Water
Burgess If20 Clay
Mistron ZCS talc
Indulin W-l
Calcium Chloride
Potassium ricinoleate
Coal tar - 5% rubber mix
Coal tar - 5.130 kg
Baker Fine - 0.270 kg
9 kilograms
3 kilograms
60 grams
4.5 kilograms
7.2 kilograms
1.2 kilograms
0.6 kilograms
60 grams
60 grams
60 grams
5.4 kilograms
FORMULA TE-6
Water
Burgess //20 Clny
Mistron ZCS talc
Indulin W-l
Calcium Chloride
Potassium ricinoleatf
7.2 kilograms
1.2 kilograms
.6 kilograms
60 grams
60 grams
60 grams
-------
A-3
FORMULA TE-6 (Continued)
Coal tar - 5% rubber mix
Coal tar - 5.130 kg
Xylos Ix - 0.270 kg
5.4 kilograms
FORMULA TE-7
Water
Burgess #20 Clay
Mistron ZCS talc
Indulin W-l
Calcium Chloride
Potassium ricinoleate
Coal tar - 5% rubber mix
Coal tar - 5.130 kg
Union Carbide - 0.270 kg
7.2 kilograms
1.2 kilograms
0.6 kilograms
60 grams
60 grams
60 grams
5.4 kilograms
FORMULA TE-8
Water
Burgess #20 Clay
Mistron ZCS talc
Indulin W-l
Calcium Chloride
Potassium ricinoleate
Coal tar - 25% rubber mix
Coal tar - 4.05 kg
Union Carbide - 1.35 kg
7.2 kilograms
1.2 kilograms
0.6 kilograms
60 grams
60 grams
60 grams
5.4 kilograms
-------
A-4
FORMULA TE-9
Water
Burgess //20 Clay
Mistron ZCS talc
Iftdulin W-l
Calcium Chloride
Potassium ricinoleate
Coal tar - 5% rubber mix
Coal tar - 5.130 kg
Baker Fine - 0.270 kg
7.2 kilograms
1.2 kilograms
0.6 kilograms
60 grams
60 grams
60 grams
5.4 kilograms
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FIGURE A-l. 1 YEAR EXPOSURE - SAMPLE TE-1
FIGURE A-2. 1 YEAR EXPOSURE - SAMPLE TE-2
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<*|*&';. .; •. |...- .
i
'i
FIGURE A-3. 1 YEAR EXPOSURE - SAMPLE TE-3
t
FIGURE A-4. 1 YEAR EXPOSURE - SAMPLE TE-4
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FIGURE A-5. 1 YEAR EXPOSURE - SAMPLE TE-5
FIGURE A-6. 1 YEAR EXPOSURE - SAMPLE TE-6
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FIGURE A-7. 1 YEAR EXPOSURE - SAMPLE TE-7
FIGURE A-8. 1 YEAR EXPOSURE - SAMPLE TE-8
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-. MMfa.
FIGURE A-9. 1 YEAR EXPOSURE - SAMPLE TE-9
FIGURE A-10. 1 YEAR EXPOSURE - SAMPLE CT-C
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FIGURE A-ll. 1 YEAR EXPOSURE - SAMPLE AC
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1 REPORT NO.
EPA-670/2-74-014
2.
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
5. REPORT DATE
March 1974; Issuing Date
Scrap Rubber Tire Utilization in Road Dressings
6. PERFORMING ORGANIZATION CODE
7 AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
Benson G. Brand
9. PERFORMING ORGMWIZATION NAME AND ADDRESS
Battelle
Columbus Laboratories
505 King Avenue
Columbus, Ohio 43201
10. PROGRAM ELEMENT NO.
1DB314;ROAP 24AIN;Task 24
11 CONTRACT/GRANT NO.
EP-00500-01
12 SPONSORING AGENCY NAME AND ADDRESS
National Environmental Research Center
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati , Ohio 45268
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
Research to demonstrate the feasibility of using rubber from discarded passenger car
tires in water-thinnable emulsions of asphalt or coal tar for blacktop dressings for
driveways, etc., was conducted. Nine different compositions containing from 5 to 25
percent rubber were applied to field test site. After one year of continuous exposure
in a high traffic area, the performance of the experimental compositions appeared to
be as good as control samples. No attempts at composition optimization were made but
complete feasibility of the basic idea has been successfully demonstrated.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
kTires
Automobile tires
Emulsions
Asphalts
Road surfacing
kUtilization
Coal tar
*Scrap rubber tires
*Road dressings
11J
13B
8 DISTRIBUTION STATEMENT
Release to public
19. SECURITY CLASS (ThU Report)
Unclassified
21. NO. OF PAGES
57
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
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