Examining Mechanical Properties of Recycled Aggregate Concrete

This study develops several mid-strengths recycled aggregate concrete (RAC) mixtures. The experimental part examines three groups. The first group, natural aggregate concrete (NAC) mixtures, used 100% natural gravel aggregate. The second group (RAC-I) used a combination of natural gravel aggregate and recycled concrete aggregate (30% per total weight of coarse aggregates). The parent concrete had a compressive strength of 20-30 MPa. The third group (RAC-II) had a similar and higher percentage of recycled concrete aggregate replacement of 30%, 50%, and 100%. The reference concrete had a compressive strength of 30-40 MPa. The results revealed that the 30% substitution of recycled concrete aggregate had minimal effect on the concrete workability and mechanical properties. The shrinkage of RAC-I mixtures at an age of 112 days, is 40% higher than that of NAC mixtures. The analysis of emission indicates that RCA can be a suitable option to reduce CO2 emission.