Sustainable self-consolidating concrete using recycled asphalt pavement and high volume of supplementary cementitious materials

This study presents the results of laboratory investigation of fresh, hardened and durability characteristics of self-consolidating concrete (SCC) containing high volume of supplementary cementitious materials (SCMs) including class C fly-ash (FA) and slag (S) with recycled asphalt pavement (RAP) aggregate. Sixteen mixtures were prepared with different percentages of FA, S, and RAP. SCC mixtures were divided into four groups where each group had a different percentage of RAP replacing NCA (0%, 15%, 30%, 50%) and Portland cement being replaced by different percentages of SCMs (0%, 75% FA, 75% S and combination of 37.5% FA and 37.5% S). The water to cementitious material (w/cm) ratio for SCC mixtures in this study was maintained to be 0.4 with a target slump flow higher than 500 mm. The fresh concrete properties such as: flowability, deformability, filling capacity and resistance to segregation were measured. Moreover, hardened properties such as compressive strength at 3, 14 and 28 days and split tensile strength at 28 days were measured and durability characteristics including unrestrained shrinkage up to 90 days and chloride permeability resistance at 45 and 90 days were tested. The use of SCMs and RAP affected both the fresh and hardened properties of SCC. Analysis of experimental data showed that all the mixtures satisfied the SCC fresh properties requirements. The addition of RAP and SCMs had an adverse effect on both the compressive and tensile strength of concrete mixtures. However the use of SCMs has positive effects on the unrestrained shrinkage and permeability.