Influence of raw concrete material quality on selected properties of recycled concrete aggregates

Abstract

Recycling of construction waste is an enterprise that is extremely important as well as difficult to accomplish in terms of environmental protection. One of the possible ways of the application of the construction waste, from demolition of concrete constructions, is its re-use as recycled concrete aggregates (RCAs) in production of constructive concretes. The paper attempts to assess the influence of raw concrete material quality on selected properties of RCAs. Volumetric density, bulk density, voids, crushing strength, water absorption, mineral dust content for RCA, obtained from crushed primary concrete having different compressive strength, were examined. RCA was obtained by crushing laboratory concrete having a wide range of water/cement (w/c) ratio (from 0.35 to 0.7); it allowed to obtain the concrete having compressive strength from 30 to 60 MPa. The research also included recycled concrete with the secondary aggregate having optimal granulation (selected empirically and with the assumption of the lowest voids of the aggregate composition).