Comparative Tests of Beams and Columns Made of Recycled Aggregate Concrete and Natural Aggregate Concrete

Abstract

The tests concerning use of concrete with recycled aggregates (RAC) presented in different countries were focused on material properties. Very few serial tests were done on structural reinforced-concrete members with RAC to be compared with similar members with natural aggregate concrete (NAC). Such tests are necessary because it is difficult to predict the influence of differences in particular properties on the overall behaviour of reinforced concrete members made of various mixtures of recycled aggregate concrete. The aim of the tests presented in the paper was to determine differences in behaviour of simple reinforced concrete members made of RAC, with different contribution of recycled aggregates, in comparison with members made of concrete with natural aggregate (NAC) only. The results of replacing by recycled aggregate the coarse and fine aggregate or the coarse aggregate only were particularly taken into consideration. 16 series of beams and 5 series of columns have been selected for tests. The comparison of results showed similar bearing capacity of members in the series, and significantly greater deformations of concrete in members with recycled aggregate concrete. Differences in load-bearing capacity could be neglected in practice, but the differences in deformability should be considered carefully at beam deflection assessment, as well as at columns shortening analysis.