I-88 Pavement Rehabilitation
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Project Team:
Owner:
Illinois State Toll Highway Authority
Tollway Consultant:
Consoer Townsend Envirodyne Engineers Inc., Chicago
Design Consultant:
Beling Consultants Inc., Moline, Ill.
Rubblization Consultant:
Marshall R. Thompson, P.E., Champaign/Urbana, Ill.
General Contractor:
Stahl Construction, DeKalb, Ill.
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A Z-pattern roller follows the breaker to additionally crush and compact the broken pavement.
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This pilot project, undertaken from July to October, involved rehabilitation of four miles of I-88 east of DeKalb, Ill., using a relatively new technique called rubblization. In this process the existing pavement is broken up into pieces six to nine inches or smaller, rolled in place and then overlayed with asphalt. The Illinois Tollway enlisted the consulting services of Marshall Thompson, professor emeritus at the University of Illinois, Urbana/Champaign, and an expert on the rubblization process.
Prior to rubblizing, the top asphalt layer is stripped from the roadway to allow the machine to make contact with the concrete. The I-88 project is the first attempt to break 14-in.-thick pavement. To rubblize the concrete, a multihead breaker traveled at a walking pace and broke the entire lane in one pass. The breaker, supplied by Antigo Construction, Antigo, Wis., is self-propelled, carrying 1,000- to 1,200-lb. drop hammers mounted laterally in pairs. The machine can operate without a barrier between the equipment and the adjacent lanes of open traffic. A "Z" pattern roller follows the breaker to additionally crush and compact the broken pavement. An 8-in. layer of asphalt was then placed in three lifts over the newly created aggregate.
Advantages of rubblization include elimination of the need to continuously patch the road and repair joints damaged from "freeze-thaw," and elimination of reflective cracking by placing an entirely new 10-in. layer of asphalt over the rubblized concrete. This quick, easy form of rehabilitation allows traffic to continue with minimal disruption over a shorter period of time. The method increases pavement life expectancy, and is less expensive than removal of the concrete and total replacement of the road. The construction cost for the pilot project was $3.7 million. The direct savings in construction cost by using the rubblization technique as opposed to removal of the old pavement and replacement with imported material was estimated to exceed $1 million.
Several judges noted that the innovation of the project deemed it an award winner.
"It's the first of its kind," said Michael Yanku, resident engineer for Beling Consultants, Moline, Ill. "The overall process is the right approach for the Tollway. We're allowed to leave what' s in place and build on top of it."
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Source: Midwest Construction Vol.1, No.12
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