REPORT ON USE OF RUBBER CRUMB

FROM WASTE RUBBER TIRES

IN HIGHWAY CONSTRUCTION

By

G. H. Heiman

September, 1980

ii.-

INTRODUCTION

The disposal problems of one million(l) used car and truck tires in the Province of Saskatchewan encouraged the Depart­ment of Highways to pursue some known uses of rubber crumb. The use of rubber asphalt was developed in Phoenix by C.H. McDonald(2) and used successfully as a seal coat binder. The department had to verify the process could work in cold climates and compare economically with our established processes.

The evaluation stage of the rubber asphalt binder is in pro­gress and will continue. The process has shown enough promise and potential that this report can be written to show that the department should continue to USe rubber asphalt binders.

This continued use will provide the Department of Industry and Commerce with a commitment on the quantity of used tire crumb Highways can use annually. This quantity should enable a decision to be made about a rubber grinding plant in Saskatchewan.

This report will review the history and uses of recycled tires in highway construction, the economics of using rubber asphalt binders, and recommend how the department should proceed to use rubber asphalt binders (RAS).

ACKNOWLEDGEMENTS

The efforts of J. L. M. Scott, Assistant Surfacing Engineer from Surfacing Branch, in compiling perform­ance data, developing specifications, and coordina­tion of activities in the rubber asphalt seal programs.

The work of Sahuaro Petroleum in providing contractual service and technical information is noted with thanks.

The work of Works Branch crews, District seal crews and residents G. Gray and Al McLeod, is noted with thanks.

Typing by Janet Dawson, Engineering Division, is gratefullY acknowledged.

fii.

TABLE OF CONTENTS

LETTER OF TRANSMITTAL

INTRODUCTION

AC KNOWLEDG HIENTS

TABLE OF CONTENTS

LIST OF TABLES

CONCLUSIONS

RECOMMENDA TI ONS

DETAILED DISCUSSION

A Background A 1.1 Disposal of Used Tires A 1.2 Reports

A 1.2.1 Report for Submission to Inter­department Committee on the Recycling of Discarded Rubber Tires

A 1.3.1 The Potential for Waste Rubber Utilization in the Prairie Provinces

A 2.1 Rubber Asphalt Development

i

ii

iii

iv

vi

1

2

3 3 3

3

4

5

B Use of Rubber Asphalt in Pavements 7 B 1

B B B B

B 2 B B

B 3

Rubber Asphalt Binders in Seal Coat 7 Applications

1.1 Sahuaro Petroleum Process (Overflex) 7 1.2 Arizona Refining Co. (ARCO-Arm-R-Shield) 7 1.3 Emulsion Rubber Asphalt 7 1.4 Rubber Aspha 1 t In ter 1 ayer (SA~II) 7

Rubber Crumb in Asphalt Concrete 8 2.1 City of Toronto-University of Toronto 8 2.2 SKEGA 8

Rubber Asphalt Crack Filling 8

C Rubber Asphalt Uses in Saskatchewan C 1 Process

8 8 9 9 9

C 2 Rubber Asphalt Surface Types C 2.1 Original Usage C 2.2 Revised Usage

-iv.

(Table of Contents Con't.)

D

C 3 Life Cycle Costing C 3.1 Stage D Pavements C 3.2 Stage C Pavements C 3.3 Stage B Pavements C 3.4 Rubber Asphalt Seals of Asphalt

Concrete C 4 Performance of Rubber Asphalt Binders

C 4.1 Expected Performance C 4.2 Actual Performance C 4 .3 General Comments on RAS Performance

Implementation of Rubber Asphalt Seals in Saskatchewan

D 1 Program D 2 Rubber Asphalt Seal Crew D 3 Organization and Responsibilities

D 3.1 Engineering Division D 3.2 Operations Division D 3.3 Works Branch

D 4 Equipment D 5 Patents/Royalties D 6 Rubber Crumb

BIBLIOGRAPHY

9 9

11 12 13

14 14 14 16

16

16 17 17 17 17 17 17 18 18

20

v.

vi.

LIST OF TABLES

Page

TABLE 1 - Unit Cost 21

TABLE 2 - Application Rates 21

TABLE 3 - Combined Cost 22

TABLE 4 - Life Cycle for Staged Pavements 23

TABLE 5 - Li fe Cycle for Stage C Pavements 24

TABLE 6 - Li fe Cycle for Stage B Pavements 2S

TABLE 7 - Life Cycle for Stage Rehabilitation

A Pavement 26

CONCLUSIONS

1. The rubber tire disposal problem in Saskatchewan could be solved by establishing a rubber grinding plant. The Department of Highways & Transportation can use up to 2200 tonnes of rubber crumb annually for a cost benefit of $13.6 million over ten years. The department could use an additional 1175 tonnes of rubber crumb annually at no additional cost to the highway budget.

2. The use of rubber asphalt seals for sealing asphalt concrete is more effective in providing a seal than our present high float emulsion seals.

3. The inability to achieve adequate ride consistently on subgrades and the current performance of rubber asphalt seals on subgrade precludes that rubber asphalt seals should not be used directly on subgrade. A cond­ition to this statement is if the government and the department agrees that a rubber crumb plant be established to alleviate the used tire disposal problems a system could be implemented to use more rubber crumb in high-way construction.

4. The use of cold mix and high float seal requires further evaluation as an alternative to AMOS based on test sections constructed on C.S. 42-2 in 1978.

5. Rubber asphalt seals CRAS) are less prone to bleeding than softer asphalts, have very good skid numbers, and are capable of flexing to surface deformations even at cold temperatures.

6. Rubber asphalt binder spreading equipment is proven to be capable of spraying the rubber asphalt binder. The equipment can also spray other seal binders.

RECOMMENDATIONS

1. The rubber asphalt seal program should concentrate on sealing asphalt concrete surface types.

2. The department should initially establish one seal crew to apply rubber asphalt seals. This crew can spray rubber asphalt from June to about mid-September. This period of time should require approximately 1950 tonnes of rubber crumb and be able to cover about

2 .

400 kilometres of highway. The crew should be scheduled to do high float seals before and after the rubber asphalt seal season.

3. The department should purchase three Bear Cat distrib­utors (similar to Sahuaro's) and a Bear Cat blender for the seal crew. The total capital cost of this equipment would be approximately $500,000 and will be recaptured, due to reduced rental rates, in 2 or 3 years.

4. The department should inform the interdepartmental committee, set up to establish a rubber grinding plant, that we will be using 1950 tonnes of rubber crumb annually for up to 7 years.

5. The department has to evaluate the possibility of using 20 mm cold mix (oil treatment) over an SOS versus the 50 mm cold mix (AMOS) over an SOS to check cost benefits.

3.

A. BACKGROUND

ALI

A 1. 2

Disposal of Used Tires

The Cities of Regina and Saskatoon approached the Provincial Government for assistance to the problem of disposal of used rubber tires. Tires were burned quite regularly at sanitary land fills prior to the introduction of new environmental regulations. Tires now collect in piles in the order of one million tires per year with no easy means of disposal. The approach by the cities to the provincial government resulted in an ad-hoc committee with representatives from Department of Industry and Commerce, Environment, Health and Highways, to investigate the problem. The following sections will summarize conclusions and re­commendations of various reports that have resulted from their ad-hoc committee.

Reports

A 1.2.1 Report for Submission to Inter-Departmental Committee on the Recycling of Discarded Rubber Tires el )

A 1.2.1.1 - Conclusions

i)

ii)

iii)

No inexpensive way to grind rubber tires and most promising use is in asphalt pavement.

Coarse chips could only be produced with mobile equipment.

Field testing of rubber asphalt binders would be required.

A 1.2.1.2 - Recommendations

i) Purchase of Tire Gon equipment and operated in Regina and Saskatoon for year to establish cost.

ii) Provincial government should support Fabco Machine Limited in development of a grinding unit.

iii) In 1975 if test sections prove satisfactory, a detailed study should be undertaken to evaluate new equip­ment and long term benefits of rubber grinding industry is warranted for Saskatchewan.

4 .•.

A 1.2.1.3 Action Taken

A 1.3.1

The action taken from this work was that rubber asphalt test sections were con­structed in 1975 by the Department of Highways. The test section is discussed later in this report. The second action that was taken was commissioning a con­sultant to investigate the warrants and benefits of a rubber grinding industry for Saskatchewan.

The Potential for Waste Rubber Utilization in the Prairie Provinces(3)

A 1.3.1.1 Conclusions

i) There is a sufficient volume of scrap tires produced on prairies to form a sound base for viable recovery scheme.

ii)

iii)

A sizeable and expendable market for crumb rubber exists in Saskatchewan, Alberta and Manitoba at a selling price of 30¢/kg.

The recovery of rubber crumb from all types of tires is technically feasible using cryogenic processing.

iv) Institutional and government con­straints to recycling of rubber products centre around failure to promote conservation of our resources. Little effort has been made to en­courage retreading or the use of high quality longer life tires, both of which would significantly reduce waste tire volumes.

v) One central plant exhibits more favourable economics than three central plants in each province.

vi) A central plant in Regina constructed at a cost of $2,145,000 to process 5500 kg/hr at a cost of 49¢/kg in 1979. Projected to produce at 16¢/kg in 1988 after capital repayment has been complete.

A 2.1

A 1.3.1.2

A 1.3.1.3

5 :

Recommendations (summarized)

i) Government should:

a) Consider methods to increase levels of scrap tire utilization.

b) Encourage use of retread tires.

c) Provincial legislation phased in to forbid disposal of tires at land fill to ensure supply of rubber tires for grinding plant.

ii) A crown corporation should be formed to operate a rubber recovery plant in Regina.

Action Taken

The above report showed benefits over cost of $118,000,000 over ten years by using rubber asphalt seal coats on highways. This factor has been downgraded some by reduced program and high application cost. The potential use of rubber seals for Saskatchewan is about 1.7:1 benefit cost ratio over ten years. The province has continued to use rubber asphalt seal coats through to 1980.

The Department of Environment and Industry and Commerce recommend that since Highways was the biggest potential user of rubber, they investigate getting a rubber grinding plant established. This is started and this report is being written to decide to con­tinue or drop the establishment of a rubber grinding plant.

Rubber Asphalt Development

Rubber asphalt binders were developed by C.H. McDonald(2) in the mid-sixties. The rubber asphalt binder has been in Phoenix Arizona from 1967 with remarkable success in sealing cracks in asphalt concrete pavements.

J.L.M. Scott pursued this work with limited success due to problems with mixing the rubber asphalt and with spraying the mixture in 1971.

6. '

The rubber tire disposal problem (1) re-ignited an

interest in the Department to construct a test section in 1975. The test sections were constructed by R.W. Culley, Research Branch, on Control Section 47-4 and Wascana Parkway. Rubber asphalt binders proved to be difficult to mix and spray using a standard distributor. Rubber crumb was hard to mix, the mixture was difficult to spray, and rubber settled out in the tank. These test sections, which are still in existence, were the basis for cost analysis in the report "The Potential For Waste Rubber Utilization in The Prairie Provinces" (3) and further development work by Surfacing Branch.

The Rubber Asphalt binder was applied successfully in Phoenix by Sahuaro Petroleum Limited. A contract was let out to construct nine 3.1 kilometre test sections in 1978. Sahuaro Petroleum had developed special equipment to spray the rubber asphalt binder. Three items of concern arose out of the construction of these test sections.

The first con"~ern was the high cost of construction of these seals. There were three reasons for this high cost which are; the additional cost due to the rubber crumb, the slow production rates achieved and the high contract price for spraying the asphalt binder. The production rates (which have already been achieved) and the purchase of equipment by the Department (lowers the rental rate) will lower the cost substantially.

The loss of aggregate due to poor retention that occurred and snow plow damage, that occurred in the 1978 work, has largely been overcome by control of viscosities of the rubber asphalt.

The third area of concern is the problem of getting a reasonable ride on seals on subgrades. The ride proble~associated with are not easily overcome on the sub grade and this limits the use of seals on sUbgrade.

The use of rubber asphalt has continued with a con­tinuing improvement in all aspects that could cause the system to fail. The details of uses and benefits will be shown in the rest of the report.

7.

B. USES OF RUBBER IN PAVEMENTS

B.1 Rubber Asphalt Binders in Seal Coat Applications

B 1. 1

B 1. 2

Sahuaro Petroleum Process (Overflex)

The overflex system is one of the two systems that uses a rubber asphalt mixture for binder for seal coat operations. The overflex system uses formulation patented by C.H. McDonald. This company developed a distributor that can mix, react, keep in suspension and spray the rubber asphalt mixture. This is the process that has had widest use for the longest time in the U.S.A.

Arizona Refining Company (ARCO's Arm-R-Shield)

This is a rubber asphalt binder that has been claimed (by ARCO) that is equivalent to the Overflex System. This Company concentrated on using existing equipment to spray the rubber asphalt binder. The ARCO rubber asphalt binder uses a finer rubber crumb than the Overflex System, which also requires a blend of valcanized and de­valcanized rubber. The ARCO process uses a heater blender tank to mix the rubber asphalt.

This process has not been in use as long as the Overflex System with fewer reports for performance evaluation. The Department placed a section in 1979 which will be evaluated for performance.

B 1.3 Emulsion Rubber Asphalt

B 1. 4

Pounder Emulsion have been in the process of development of a rubber emulsion development. As with all emulsions, we are not sure of the total make up of the product. This development has not been successful to date. As Pounder has been using the Department for some of its testing, we will be one of the first agencies to know of its success.

Rubber Asphalt Interlayer (SAMI)

The Over flex and Arm-R-Shield systems have both been tried to stop reflective cracking through overlays. The rubber asphalt binders have been one of the better systems developed to stop reflective cracking. It is not conclusive that it is a cost effective, but early results look promising.

8.

B.2 Rubber in Asphalt Concrete

B 2.1.1 City of Toronto - University of Toronto(~)

Rubber crumb has been mixed in an conven­tional asphalt concrete mixture and a claim, based on laboratory work, made that pave­ment life will double. This factor

B 2. 1 . 2

will take many years to verify. There is a small test section on the Regina by-pass containing rubber crumb using this system. This was placed in 1978 and requires long term evaluation to prove benefits. This process is being monitored by Surfacing Branch.

SKEGA

This is a Swedish development using larger rubber crumb particals. The claim for this process is that less ice forms on the surface. There is presently a test section built in Alaska using this process. The results of the Alaska experience will be actively monitored.

B.3 Rubber Asphalt Crack Filling

The rubber asphalt binder used for seal coat work has also been used to crack fill. This is under a seperate research and test section construction at the present time. Initial results show that this product may be the first product that we have used that has kept a crack sealed for more than one year. Further test sections have to be constructed to evaluate the product, the application method and cost data.

C. RUBBER ASPHALT USES IN SASKATCHEWAN

C.l Process

The department uses the Overflex system as the process to use scrap rubber crumb. This system was chosen as it had been in use in Arizona since 1966 of which some of the original work is still functioning.

The other systems described have not had a life history that allows for prediction of performance life.

FHWA have constructed evaluation sections in some of the states. To date, reports only indicate what was constructed and no performance reports have been written.

9 .~

The decision to use Overflex is reversible as the special equipment is usable as a distributor for conventional binders.

C.2 Rubber Asphalt Surface Types

C 2.1

C 2.2

Original Usage

R. W. Culley in the 1975 test sections was looking for a replacement for oil treatment. The rubber asphalt seal had to last for three years to break even in cost with the department's oil treatment. The original life expectancy was lowered from Arizona's eleven years to seven years.

The use of rubber asphalt seal in place of oil treatment will require the department buy the special distributors to lower the cost and the acceptance of the ride achieved with a seal on subgrade.

Revised Usage

Rubber asphalt seal coat work has not progressed as projected in the Wardrop Report(4). Rubber asphalt binders are more costly than first estimated, snowplows peeled off the seal coat, and the special distributors are requlrea.

C.3 Life Cycle Costing

Life cycle costing for the various potential uses for rubber asphalt seal coats have been completed for Stage D, Stage C and Stage B pavements. A life cycle costing is also provided for seal coat work on asphalt concrete.

C 3.1 Stage D Pavements

C 3.1.1 Alternative 1

The present worth of a Stage D (oil treatment) is $22,463/per kilo­metre (Table 4). This is based on the present compaction specification with an SOS in place. The old maint­enance seal cycle was used as that is known to work. The annual maintenance cost is the 1979 provin­cial allotment.

C 3.1.2 Alternative 2

The present worth using a rubber asphalt seal coat in place of oil treatment is presently $25,523 per kilometre and is projected to cost $20,826/km when we own the distrib­utors (Table 4).

The maintenance is expected to be some­what less than a cold mix due to less spot sealing and hand patching required because the rubber asphalt is more flexible and waterproof. The seals that are required on oil treatments in future years have been applied the same as Alternative 1. The performance to date has not been conclusive as some sections have less patching and maintenance and others the same.

C 3.1.3 Alternative 3

This is a sensitivity check on per­formance. If the rubber asphalt is no better than oil treatment it will still cost less than Alternative 1 by $269 per kilometre (Table 4).

C 3.1.4 Alternative 4

Ride on sub grade has been very incon­sistent on subgrades in the past. This alternative USes 150 t/km of cold mix for ride improvement padding. The remainder of the factors are the same as Alternative 2. This alter­native cost $479/km (Table 4) than the normal oil treatment.

C 3.1.5 Alternative 5

Cold mix for padding, rubber asphalt seal, and no maintenance improvement is used for this alternative. This results in a extra cost of $2,102/km (Table 4) than a normal oil treat­ment.

C 3.2

C 3. 1 . 6

.11.

RAS on Stage D

Rubber asphalt seal in place of oil treatment will be economical if no padding for ride improvement is required. The amount of padding for ride improvement on new oil treatments is not known, but likely occurs at present also, but assuming it is very minimal the use of rubber asphalt seals in place of oil treat­ment should be limited to good riding sUbgrades.

Stage C Pavements

C 3.2.1 Alternative 1

The present worth of a Stage C pave­ment is $44,514/km (Table 5). This cost is for the surfacing after the grading SOS and a rehabilitation of 50 mm AC at year seven. The maintenance cost is the 1979-80 allotment.

C 3.2.2 Alternative 2

The present worth of using rubber asphalt seal coat is $32,805/km presently and projected to cost $25,666/km. There is a potential saving of $II,70g/km to $16,513/km by using rubber asphalt seal in place of AMOS.

C 3.2.3 Alternative 3

This alternative includes cold mix for ride improvement. The cold mix will likely be required to achieve ride levels comparable to AMOS pavements.

C 3.3

C 3. 2 . 4

The present worth is $34,681/km and projected to be $28,OOI/km. This

~l 2 .

is a saving of $9,833/km to $16,513/km using RAS in place of AMOS.

RAS for Stage C

The economics to replace AMOS with rubber asphalt seal is a net savings to the department.

The program should continue to replace AMOS treatment with RAS but cold mix has to be used to improve the ride on the subgrades. Present indica­tions are H.F. seals could do a similar service.

Stage B Pavements

C 3.3.1 Alternative 1

The seal base with a double seal has a total present worth of $30,247/km exclusive of the subbase and base on initial construction.

C 3.3.2 Alternative 2

The rubber asphalt is placed on a single seal coat due to construction logistics. A seal in year 4 is left off because the RAS is projected to last approximatelY 7 years. The total present worth cost is $38,804/km presently and projected to be $31,407 per km.

C 3.3.3 RAS on Stage B

The extra cost of rubber asphalt bases on base are $1,160 to $8,557 higher than the present double high float seal. The performance is not likely to be improved enough to effect this cost, by improvment of RAS product.

C 3.4

13.

Rubber Asphalt Seals on Pavements (Table 7)

C 3.4.1

C 3.4.1

Alternative 1

The present life cycle of asphalt concrete uses a high float seal which delays the need for an overlay approxi­mately 2 years. Two of these seals can be placed to delay cost by 4 years. The total present worth of the high float seal and overlay placed four years after the initial seal is $27,120/km.

Alternative 2

Using rubber asphalt seal for above process it is estimated that the asphalt concrete rehabilitation could be delayed for 7 years. This delay is based on our 1978 test sections and the 12 years of life achieved in Phoenix. The total present worth of this alternative is $27,496 now but project to be $23,213/km.

C 3.4.2 Alternative 3

A system is being used in the U.S.A. that is said to reduce the overlay thickness required because of reflec­tive cracking. This is not totally proven yet but does look more promising than the use of fabrics and other mat­erials to stop reflective cracking. The total present worth of this method is $37,756/km presently and projected to $33,059/km. This is not very attractive at this time due to cost and questionable performance.

C 3.4.3 RAS in Rehabilitation

The economics show that a rubber asphalt seal should be used for seals on asphalt concrete. This is the area that has the highest cost benefit and is likely to prove out in terms of performance.

14.

C.4 Performance of Rubber Asphalt Binder

The life cycle cost implies a performance expect­ance that has been extrapolated from our experience and experience in the U.S.A. The performance aspects are in two parts, the expected performance and actual performance to date.

C 4.1

C 4.2

Expected Performance

Memo of December 12, 1978 of J.L.M. Scotts outlines expectations of rubber asphalt seals on subgrades. These expectations were:

a} In the travelled way a sealed subgrade will structurally out perform a non-sealed oil treatment or AMOS.

b} The ride of a seal on subgrade would be worse than a cold mix initially, but with time, the ride on the seal would be no worse than on a cold mix.

c} Spot sealing would not be required for cracking, but would be required for surface breaks.

d} General reseals would only be required every seven years rather than every four years on oil treatment.

e} Padding would be required to correct rutting.

Actual Performance

The actual performance is still an estimate for expected end life has not been reached in the province. The expected performances will likely be achieved on control sections where the sub grade is sound and the aggregate was retained in the rubber asphalt binder.

C 4.2.1 1975 Test Sections

Two short test sections were constructed using locally available equipment on Wascana Parkway and C.S. 47-4. Wascana Parkway used light weight aggregate which was stripped off due to a heavy rainfall shortly after its placement. The section is still in place with very good skid resistance and only large reflective cracks have opened up to date.

C 4.2.2

C 4.2.3

Control Section 47-4 is still in place with about 30% of the area covered with padding and seal. The padding was to fill rutting due to sideslope shear and some potholes. The section maintenance personnel has indicated that less hand patching has occurred on the section.

1978 Test Sections

~ 1 5 .

Eight test sections were constructed of which five are not considered suc­cessful. The first reasons Some of these test sections failed is because of inadequate subgrade preparation. Inadequate sub grade preparation should not be charged against rubber asphalt binder. The second reason five of these test sections failed is that we experience aggregate retention problems using graded aggregate. The aggregate in place is dirty and we also experienced viscosity control problems.

The sixth section, on C. S. 48-02, has one section in good condition, and 20% of other sections failed. Sub­stantial cold mix padding has also occurred because of loss of stone and surface pick outs.

The two seals on asphalt concrete are performing with some stone loss but no reflective cracking of cracks other than the temperature related transverse cracks.

1979 Program

The rubber asphalt was placed on sub­grade and all sections are providing a sealed surface. The stone retention problem observed in the 1978 test section was greatly improved.

The snowplow damage on all sections was not observable after the 1979-80 winter. The snowplow damage is likely related to lack of stone retention, therefore, the better stone retention that occurs the less snowplow damage that will occur.

C 4.3 General Comments on RAS Performance

Rubber asphalt binders are very black which can result in poor appearance of a seal that looses stone. This appearance will not effect the performance of the seal as rubber asphalt seals tend not to bleed, and provide good skid values even though stone loss has occurred.

"16.

The rubber asphalt seals have shown that they effectively cover cracks in pavements other than transverse temperature cracking.

D. IMPLEMENTATION OF RUBBER ASPHALT SEALS IN SASKATCHEWAN

D.l Program

The cost and performance factors show that the rubber asphalt binders can be used for -

1 . 7

Seals on asphalt concrete. Seals in place of Stage C pavements with a condition that some cold mix be used for ride improvement.

3. Seals in place of oil treatment if subgrade has good ride.

The number of miles that could use RAS annually over the next ten years(5) in the categories are:

1. 346 km of AC pavements 2. 1992 km of Stage C pavement 3. 1348 km of Stage D pavement

A rubber asphalt seal crew such as we are using today could possibly place 400 km of rubber asphalt seal annually. The program for rubber asphalt should start June 1st and end September 15th To place RAS on all the potential projects we would require nine rubber asphalt crews.

The department should proceed with this program in an ordered manner as it requires considerable investment in equipment for the crews and our asphalt plants would also be without work if we went into full potential rubber asphalt seal program.

The department should set up one crew with required equipment and concentrate on the RAS on asphalt concrete for a period of two to three years. This means that most of the seal will be placed on asphalt concrete for the next two or three years.

The seal crew should be scheduled to do high float seals before and after the rubber asphalt season.

D.2 Rubber Asphalt Seal Crew

The initial RAS crew should be left under the manage­ment of Works Branch so that it can work in all districts without travel and union agreement problems.

This arrangement is also useful to improve technique of application.

D.3 Organization and Responsibilities

The present organization and responsibilities give a operational program. The following is a summary of the present set up with responsibilities.

D 3.1

D 3.2

D 3.3

Engineering Division

i) Develop RAS program for approval ii) Provide technical assistance when

required iii) Provide rubber asphalt testing services

Operations Division

i) Provide engineering supervision. This should stay central as long as one crew is used. A volunteer system could be used to select residents.

ii) Order and acquire materials - rubber, asphalt and aggregate.

iii) Setup schedules iv) Program should be administered through

one district or head office operations staff while only one seal crew is set up.

Works Branch

i) Will provide seal coat crew and equipment to apply rubber asphalt seal coats and high float seals before and after rubber asphalt seal season.

D.4 Equipment

The department should purchase the following equip­ment to complete the Works Branch seal crew.

1. Rubber asphalt mixer blender 2. Three Bear Cat distributors built similar to

Sahuaro's equipment.

The mixer blender will cost approximately $50,000 and the three distributors will cost $450,000.

The remainder of equipment requirements have already been established.

D.5 Patent Royalties

The rubber asphalt binder processes are all pat­ented processes in the U.S.A. and some in Canada. This means under normal circumstances a royalty fee should b~ paid for the use of the product.

The development, research and department involvement places a question on whether the department is using a process in Canada before application was made to patent process in Canada.

R. W. Culley has expressed very strongly that it is his judgment that we would not be infringing on a patent if we continued to use the process without paying royalty.

The department has to establish if it would be infringing on a patented process, if it is found that this is so, the department will have to make an official agreement to use the process with Sahuaro Petroleum.

The agreement to use the process will have to be negotiated as we have made contributions to the development to the process use in Canada. The agreement should likely be modelled after the agreement we have with Shell Canada for use of the thermopatch system.

D.6 Rubber Crumb

The rubber crumb supplies are not in short supply but have some small producers that cannot supply our total needs.

The following proposed tender method would be superseded if the province gets involved with a rubber grinding plant.

The rubber grinding industry is in a growth phase at this time which mades it beneficial to continue to use the public tender system to acquire rubber crumb. Some of these plants are small and would not be able to supply us with our total needs without a large lead time and/or a splitting of the tender.

18.

The tender should be let by October before the season the rubber is required with delivery starting in April and completed by June 1st. The tender should be one tender with lots for project. The suppliers would be allowed to bid on any or all lots or any combination thereof. This would allow small suppliers to commit production to the rubber crumb supply and also indicate early what the total demand is for rubber crumb.

19.

BIBLIOGRAPHY

1. B. Zuk, R. W. Culley, Report for submission to inter­departmental committee on "The Recycling of Discarded Rubber Tires", Internal Report, 1974.

2. McDonald, Charles H., "Asphalt Rubber Compounds and Their Applications for Pavement", 21st Californian Streets and Highways Conference, January, 1969.

3. Wardrop, lV.L. and Associates Ltd. and Sue-MECO INC., 1974 . "Th e Pot e n t i a 1 for ]V a s t e Rub be rUt i 1 i z a t ion in the Prairie Provinces", August, 1977.

4. Piggott, ~l.R. et al "Improved Hot Mix Asphalts Containing Reclaimed Rubber", AAPT Proceedings, 1977.

5. Internal memos Heiman to Sheard, December, 1977 re: potential use of RAS in province.

6. J. L. ~1. Scott's report of July, 1980.

20.

TABLE 1 UNIT COST

Petroleum Products (1980 prices includes haul $12/ton)

AC 1.5 ~lC 30 HF 250S Kerosene

Aggregate (Tender awards 04/80 - 04/80)

Oil Treatment - Type 113 x Haul Seal Coat and Haul

Rubber

Hot Mix - contract price

Work Items (Works cost)

PSG Prime

Mixing Laying Flushing

TABLE 2 APPLICATION RATES

Oil Treatment

Mix Prime Flush

310 t/km (550 tim) 4.5% asphalt 1.25 L/m 2 or 9250 L/km .3 L/m 2 or 2220 L/km

AMOS

Mix 1080 t/km

Seal Coat (HF)

Emulsion .3 ga/yd 2

Aggregates HF 40 lb/yd 2 Rubber Asphalt Binder Aggregate 50 lb/yd 2

- 1. 63 L/m 2

- 22 kg/m 2 - 2.57 L/m 2

- 27 kg/m2

21.

$16l.44/tonne or $.1644/L $0.1637 $0.1489 $0.2066/L

$3.58/t $3.l3/t

$353.39/t

$10.19/t

$0.30/m2 .047/m 2 tender awards and

2.56/t 2.20/t

.052/L

works actual

HF Seal

Labour

TABLE 3 COMBINED COST PER km

Asphalt 1.63 x (7400) x .1489 Aggregate 22 x 7400 x 3.12 ~ 1000

TOTAL

Prime

~lC 30 Application

TOTAL

Oil Treatment (310 t/km)

Mixing Laying Asphalt 310 x .045 x 161.44 Aggregate crush & haul Flush, Materials & Application Misc. and mobilization

TOTAL

AMOS

Mix Laying Asphalt 1080 x 0.045 x 161.44 Aggregate crush & haul Flush Misc. & mobilization

TOTAL

Rubber Asphalt Seal - Current

Labour & Equipment (Works est. includes PSG and prime)

Aspha1 t Rubber Aggregate Kerosene 8 go

TOTAL

7.4 m

1294 1796

510

3600

1541 347

1888

794 682

2252 1110

460 52

5350

7200

2344 1714

625 314

12197

WIDTH 9.0 m

1500 2184

620

4304

1874 423

2297

2764 2350 7845 3866

560 145

17530

8760

2850 2084

760 381

14835

11.4 m

2000 2766

782

5548

10702

3611 2640

929 483

18365

Rubber Asphalt Seal - Projected (Department owns equipment and does work)

Labour & Equipment Asphalt Rubber Aggregate Kerosene

TOTAL

Hot Mix - Vensity 2400 kg/m 3

2848 2046 1667 625 314

7500

(Standard 7420)

3463 2850 2084

760 381

9538

(75 mm) 20909

In9V

4387 3611 2640

96::: 483

12083

(50 mm)

13939 10221 1399

-':-.'

22.

TABLE 4 LIFE CYCLE COST FOR STAGE D ALTERNATIVES

ALTERNATIVE 1

Oil Treatment Present compaction specification - Old Maintenance cycle 8!16 p.w.

YEAR OPERATION COST PRESENT WORTH

0 Mix & Lay Oil Treatment 5350 5350 1 HF Seal 3600 3333

Annual ~Iaintenance (70/80 Allotment) 1024 9340 5 HF Seal 3010 2048 9 HF Seal 3010 1505

13 HF Seal 3010 1106 17 End Life

TOTAL 22682

ALTERNATIVE 2

RAS - Present compaction specification - Old Maintenance cycle 8% p.w.

PRESENT COST PROJECTED COST YEAR OPERATION INITIAL COST P.W.

0 Rubber Asphalt Seal 12197 12197 7500 7500 Annual Maintenance 850 7753 850 7753

5 HF Seal 3600 2450 3600 2450 9 HF Seal 3600 1800 3600 1800

13 HF Seal 3600 1323 3600 1323 17 End Life

TOTAL COST 25523 20826

ALTERNATIVE 3

RAS - As alternative 2, assume no improvement in maintenance cost (i.e. as per oil treatment)

TOTAL COST 27110 22413

ALTERNATIVE 4

RAS - As alternative 2, but add 150 t/km cold mix for ride improvement before seal cost $2,335/km

TOTAL COST 27858 23161

ALTERNATIVE 5

RAS - As alternative 3, but add 150 t/km cold mix for ride improvement before seal.

TOTAL COST 29445 24784

. 23.

24 0

TABLE 5 LIFE CYCLE FOR STAGE C

AL TERNA TIVE 1

AMOS - Present compaction policy

YEAR OPERATION COST PRESENT WORTH

0 Mix & Lay 50 mm mat 17530 17530 1 HF Seal 4304 3985

Annual Maintenance (79/80 Allotment) 756 6232 5 HF Seal 4304 2929 7 Rehabili tation 17530 10229 8 HF Seal 4304 2325

12 HF Seal 4304 1709 14 End Life

TOTAL COST 44514

ALTERNATIVE 2

RAS - Present compaction policy

YEAR OPERATION PRESENT COST PROJECTED COST PoW 0 Po \II 0

0 Initial Construction 14835 14835 9538 9538 Annual Maintenance Estimate 850 7524 850 7524

5 I-IF Seal 4304 2929 4304 2929 8 Rehab 0 PSG, Prime, RAS 19662 10622 14367 7760

13 HF Seal 4304 1582 4304 1582 16 End Life

Sub-total 37442 29333 Salvage 4686 3666 TOTAL COST 32805 25666

ALTERNATIVE 3

RAS - As alternative 1, with oil treatment first to provide ride

TOTAL COST 34681 28001

TABLE 6 LIFE CYCLE FOR STAGE B

AL TERNA TIVE 1

Seal Base - Double seal, seal cost only cost initial construction

YEAR OPERATION COST PRESENT WORTI-I

0 Double seal on base 9148 9148 Annual Maintenance 600 4947

4 HF Seal 3600 2646 7 Rehabi Ii ta tion (Cost estimate from 20500 11962

B. Pulles' design) 11 HF Seal 3600 1544 14 End Life

TOTAL 30247

ALTERNATIVE 2

RAS on single sealed base

YEAR

o Annual

7 14

OPERATION

RAS seal on single HF seal Maintenance Rehabilitation End Life

TOTAL

PRESENT COST PROJECTED COST COST P.W. COST P.W.

17745 500

29097

177 45 13048 4122 500

16937 24440

38804

13048 4122

14237

31407

25.

TABLE 7 LIFE CYCLE COST FOR STAGE A REHABILITATION

ALTERNATIVE 1

Present cycle - seal on AC - AC overlay 4 to 5 years later

YEAR OPERATION INITIAL COST

0 HF Seal 3600 2 HF Seal 3600 4 75 mrn AC overlay 37640

TOTAL (19 year cycle) Sal vage

TOTAL

AL TERNA TIVE 2

As Alternative 1 using RAS in place of HF.

CURRENT YEAR OPERATION INITIAL P. IV •

RA - Seal 18365 18365 o 7 75 mm - AC overlay 37640 21962

TOTAL (22 year cycle) 40327 Salvage (15) 12831

TOTAL 27496

ALTERNATIVE 3

PRESENT WORm

3600 3086

27666

34352 7232

27120

PROJECTED INITIAL P.]V .

12083 12083 37640 21962

34045 10832

23213

Use RAS as a interlayer (SAMI) to stop reflective cracking -claim in USA that this is worth 25 mrn of AC

CURRENT PROJECTED YEAR OPERATION INITIAL P. IV • INITIAL P. IV.

o RAS & 50 mrn AC 37756 37756 33059 33059

TOTAL 37756 33059

26.