Abstract
A laboratory investigation was conducted to evaluate the performance of a moderate-strength roller-compacted concrete (RCC) made from reclaimed crushed concrete used as aggregate, Class C fly ash, and wasteplastic fibrous reinforcement. The motivation for evaluating this primarily waste composite is to develop a high-quality foundation layer for a conventional flexible or rigid pavement while attempting to address such crucial issues as the ever-increasing solid waste disposal problem, rapidly depleting landfill spaces, and conservation of natural resources. A summary is given of the findings of materials characterization studies with the following objectives: (a) to evaluate the effectiveness of recycled high-density polyethylene strips in stabilizing the tensile crack propagation through the brittle cementitious matrix; (b) to determine the strength and toughness characteristics of the composite; and (c) to suggest performance-based mixture design proportions for recycled aggregate, fly ash, cement, and recycled plastic fibers. Because an RCC pavement slab will be subjected to repeated tensile stresses under traffic loads, the study focused on instrumented split tensile and flexural tests to evaluate the performance of the foundation material. Results indicate that a mix containing only 8 percent cement and 92 percent recycled materials can achieve 28-day compressive strengths of up to 14 MPa and split tension strength of 1.5 MPa. It is found that the plastic fibers can improve the toughness characteristics significantly in split tension and moderately in flexure. Therefore, the new cement-bound composite made primarily from recycled products offers promise as an alternative material for construction and rehabilitation of highway pavements.
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