Study of Fresh, Mechanical and Durability Characteristics of Self-Consolidating Concrete Containing Recycled Asphalt Pavement with Supplementary Cementitious Materials

In recent years, the use of sustainable technologies such as supplementary cementitious materials (SCMs) and/or recycled materials in construction industry has been increased in an effort to decrease the environmental impacts of growing construction industry. This study presents the results of laboratory investigation of fresh, hardened and durability characteristics of self-consolidating concrete (SCC) containing supplementary cementitious materials such as class C fly-ash and slag with recycled asphalt pavement (RAP) aggregate. A total of sixteen mixtures were prepared in this study with different proportions of fly-ash, slag and RAP. SCC mixtures were divided into four groups with 100% Portland cement, 75% fly-ash, 75% slag and combination of 37.5% fly-ash and 37.5% slag being major binding materials. Each group of mixtures had 0%, 15%, 30% and 50% natural coarse aggregate (NCA) replaced by RAP. The water to cementitious material ratio for SCC mixtures in this study was maintained to be 0.4 with a target slump flow higher than 500 mm. During the investigation fresh concrete properties such as: flow ability, 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 properties included unrestrained shrinkage up to 90 days and chloride permeability resistance at 45 and 90 days time period. Results showed inclusion of SCMs and RAP affected both 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 strength of concrete mixtures, compressive strength of concrete mixtures decreased as the percentage of RAP was increased from 0 to 50%. However most of mixtures satisfied the IDOT strength requirement for pavements and bridge superstructure applications including those with high percentage of RAP and SCMs.