Elastic modulus of concrete made with recycled aggregates

A global literature search, in the English medium, on the modulus of elasticity of concrete made with recycled aggregates revealed coarse recycled concrete aggregate (RCA) to be most widely reported, covering 284 publications from 42 countries since 1977 and yielding a 14 500 data matrix for systematic analysis, evaluation and synthesis. The modulus of elasticity of concrete was found to decrease at a decreasing rate with increasing coarse RCA content, giving an average 16% reduction at full natural aggregate replacement. This reduction was found to be dependent on concrete strength, becoming smaller with increasing strength. The relationship between modulus of elasticity and cube strength based on the literature data was compared with Eurocode 2, showing the modulus of elasticity of concrete made with normal aggregate falling from being just below quartzite rock at 100 MPa to limestone rock at 60 MPa concrete strength; for concrete made with 100% coarse RCA, the comparable rock types were found to be limestone and sandstone, respectively. An empirical method for estimating, in conjunction with Eurocode 2, the modulus of elasticity of concrete made with coarse RCA and sustainable measures to compensate for the reduction in the modulus of elasticity are proposed.