Utilisation of waste materials for improvement of bituminous mix performances

Abstract

Reuse of waste materials has been a general issue in all walks of life. Paving industries now face serious crunch of coarse aggregates, a by-product of natural stone resources, which constitute about 70% of bituminous paving mixes. Considering this, some researchers have already taken a cue to explore use of recycled concrete aggregates (RCA). Similarly few works show that there has been improvement in bituminous mix performance by using shredded waste plastics. Taking a note of these two facts, an attempt has been made in this study to develop bituminous mixes with RCA replacing coarse aggregate fractions, the same being modified by waste polyethylene from milk pouches (WPMP). Based on an earlier study RCA was pre-treated with bituminous emulsion (PRCA) to address the issue of higher water absorption. For comparison purposes, all material variables have been considered in preparation of dense bituminous macadam (DBM) mixes with a fixed bitumen content of 5% (including residual bitumen) and polyethylene content of 2.5%, each by weight of total aggregates. The performance characteristics studied include Marshall test, indirect tensile strength, moisture susceptibility, dynamic modulus, flow number, resilient modulus and rutting. It was observed that the mixes with PRCA and WPMP offered the best results, though all mixes satisfy the Marshall and other characteristics as per requirements.