| Asphalt Rubber Technology Information Center |
Use of Rubber in Asphalt Pavements – Kansas Experience
Author(s):
Fager, Glenn A.
Origin:
Kansas
Date:
1992
Categories:
Performance
Key Words:
Asphalt rubber
Summary:
From 1990 to 1992 a total of eight rubber hot bituminous mix projects were constructed on the Kansas DOT highway
system. Of the eight projects constructed, four have been dry, and four have been of the wet process. Two projects
have been administrated through normal bid procedures. Six have been constructed through change orders and
negotiated prices. A total of approximately 616 tomes of rubber were used in the hot mix overlays. The following
preliminary conclusions are presented.
1. From the crack survey results, it is apparent the rubber may not inhibit the development of cracks in the higher
density mixes. However, even though the results are still preliminary, the gap graded mixes show the greatest
potential in reducing the amount of cracking.
2. Rubber in a gap-graded mix will prevent asphalt draining off of the aggregates during construction. This will allow a
thicker film thickness on the aggregates.
3. None of the rubber projects have rutted, but neither have the asphalt only control sections.
4. On hot recycled projects, rubber addition rates should be based on the weight of dry virgin aggregate and RAP.
Rubber absorbs a large portion of a RA-100 in a hot recycle mix. An AC-5 with rubber will reduce the asphalt absorption
and improve the aggregate coating.
Author(s):
Fager, Glenn A.
Origin:
Kansas
Date:
1992
Categories:
Performance
Key Words:
Asphalt rubber
Summary:
From 1990 to 1992 a total of eight rubber hot bituminous mix projects were constructed on the Kansas DOT highway
system. Of the eight projects constructed, four have been dry, and four have been of the wet process. Two projects
have been administrated through normal bid procedures. Six have been constructed through change orders and
negotiated prices. A total of approximately 616 tomes of rubber were used in the hot mix overlays. The following
preliminary conclusions are presented.
1. From the crack survey results, it is apparent the rubber may not inhibit the development of cracks in the higher
density mixes. However, even though the results are still preliminary, the gap graded mixes show the greatest
potential in reducing the amount of cracking.
2. Rubber in a gap-graded mix will prevent asphalt draining off of the aggregates during construction. This will allow a
thicker film thickness on the aggregates.
3. None of the rubber projects have rutted, but neither have the asphalt only control sections.
4. On hot recycled projects, rubber addition rates should be based on the weight of dry virgin aggregate and RAP.
Rubber absorbs a large portion of a RA-100 in a hot recycle mix. An AC-5 with rubber will reduce the asphalt absorption
and improve the aggregate coating.
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