Engineering Characterization of Cement-Fiber Treated RAP Aggregates

Abstract

The increased use of reclaimed asphalt pavement (RAP) materials in road construction has reduced both the amount of construction debris disposed off in urban landfills and the rate of natural resources depletion. However, source-dependent product variability or deficient strength-stiffness characteristics has often limited RAP applications in road bases. These limitations have led to new research efforts aimed at exploring novel, cost effective stabilization methods to treat RAP materials prior to their use in pavement construction. In the present work, a comprehensive series of engineering tests were performed on RAP materials treated with different dosages of Portland type I cement and with alkali-resistant glass fibers. Engineering tests included permeability, leaching, unconfined compression and small-strain shear moduli via resonant column testing. Leaching testing included pH, total and volatile dissolved solids, total and volatile suspended solids, and turbidity. Test results appear to confirm the potential of cement-fiber treated RAP as an environmentally and structurally sound alternative to non-bonded materials for base and sub-base applications in pavement engineering. BACKGROUND Natural aggregates obtained from a variety of source rocks have been traditionally used as road base materials. The extraction of these natural aggregates, however, is increasingly being constrained by urbanization sprawls, increased extraction costs and heightened environmental concerns. The use of reclaimed asphalt pavement (RAP) materials in road construction has been proven to reduce both the rate of depletion of these natural resources and the amount of construction debris disposed off in urban landfills. RAP base materials have also been reported to yield considerable savings in the overall costs of pavement construction projects. A report released by the U.S. Environmental Protection Agency in 1993 has estimated in 73 million tons the amount