Details:

Alternative Title:
Rubber modified concrete (METRO RUMAC) Evaluation : N. Marine Drive in Portland, OR , S.E. Stark Street in Gresham, OR.
Creators:
Miller, Bo
Corporate Creators:
Oregon. Department of Transportation. Engineering Services Section
Corporate Contributors:
United States. Federal Highway Administration
Subject/TRT Terms:
[+]
Admixtures Asphalt Concrete Asphalt Pavements Costs Crumb Rubber Field Tests Ground Tires Mix Design Nuclear Density Gages Pavement Asphalt Rubber Service Life Tires
Publication/ Report Number:
FHWA-OR-RD-92-14
Resource Type:
Tech Report
Geographical Coverage:
Portland (Oregon)
Corporate Publisher:
Oregon. Department of Transportation. Engineering Services Section
Abstract:
This report covers the construction in 1991 of two test pavements using asphalt modified crumb rubber form scrap tires. The pavements are on arterial roadways in the Portland, Oregon metropolitan area.

Both test pavements use a dense-graded rubber modified asphalt concrete (METRO RUMAC) developed for the Metropolitan Service District (METRO) of the Portland metropolitan area. In this process, crumb rubber made from recycled tires is mixed with aggregate before the asphalt is blended into the mix. Adjacent to the test pavements, control pavements were paved with conventional asphalt concrete. The test pavements are compared to these control pavements.

The METRO RUMAC was successfully blended in both a batch and a drum mixing plant. In both cases, the plant's exhaust gas opacity was an acceptable level. The rubberized mixes were placed and compacted by conventional equipment.

Experience on these projects showed that caution is needed in determining the mix properties by solvent extraction and in measuring pavement density by a nuclear gauge. Testing showed that two solvents commonly used in vacuum extraction dissolve finer particles of the crumb rubber. Using mathematical modeling, it was found that solvent dissolving rubber during the extraction had these effects on test results; it did not significantly affect the test results for the overall gradation of the mix, it had a significant effect on the asphalt content test results, and it invalidated rubber gradation and rubber content test results. To get accurate nuclear density test results, special care was needed when the gauge was sealed on the surface of the METRO RUMAC.

After construction, both the METRO RUMAC test sections had appearances, ride values, deflection reduction, and surface friction values similar to their respective control pavements and typical ODOT dense-graded overlays.

The METRO RUMAC mixes cost about 1 1/2 times more than their conventional counterparts. Most of this increase was due to the cost of the rubber and the expense of adding the rubber. At this time, it is not certain that the greater initial cost of these rubberized mixes will be offset by a commensurate increase in the pavement's service life.


Format:
PDF
Funding:
DTFH71-91-TE03-OR-15
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:68231ea8297c5d5c479c1d26bcaed95c5b03150ebe043c51ed31ed407b068dfd
Download URL:
https://rosap.ntl.bts.gov/view/dot/22891/dot_22891_DS1.pdf
File Type:

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