Properties of Recycled Concrete Aggregate for Unbound Pavement Construction

TLDR

Crushed concrete or recycled concrete aggregate (RCA) has been evaluated for use as pavement material in unbound basecourses, particularly in Australia where granular basecourses support thin bituminous seals. The study aims to assess the engineering properties and cyclic loading response of three South Australian basecourse products, including two RCA mixes and a virgin quartzite aggregate. Resilient modulus and permanent deformation were measured using repeated load triaxial testing on the basecourse mixes at 90, 80, and 60 % of optimum moisture content under a simplified Australian construction stress regime. RCA mixtures exhibited higher resilient modulus and lower permanent deformation accumulation than the quartzite aggregate.

Abstract

The suitability of crushed concrete or recycled concrete aggregate (RCA) materials has been evaluated for use as pavement material for unbound basecourses. This paper covers the general engineering properties and response to cyclic loading as determined by repeated load triaxial testing (RLTT). In Australia, pavements commonly consist of granular basecourses and subbases supporting thin bituminous seals (asphalt or spray—chip seal). In this paper, a study is presented of the performances of three South Australian basecourse products, nominally 20 mm. The basecourse products included two RCA materials and a local virgin aggregate (quartzite). The resilient modulus and permanent deformation behaviour of RCA mixtures were investigated at different levels of moisture contents (90, 80, and 60% of optimum moisture content), subjected to a simplified stress regime suited to Australian construction. In terms of both resilient modulus and accumulation of permanent deformation, the RCA material performed better than the quartzite aggregate.