Investigation on Tensile Properties of Roller Compacted Geopolymer and Portland Cement Concrete Using 100% Recycled Concrete Aggregate (RCA) and Reclaimed Asphalt Pavement (RAP)

In this research tensile characteristics of roller-compacted geopolymer concrete (RCGPC) using 100% recycled concrete aggregate (RCA) and reclaimed asphalt pavement (RAP) were investigated and compared with similar mixtures using ordinary Portland cement (OPC). The formation of chemical compounds in the geopolymer composite mixtures was also analyzed using X-Ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). It was revealed from the investigation that the roller compacted geopolymer concrete using 100% RCA and RAP exhibited satisfactory tensile properties. The results showed that flexural, split tensile, and semi-circular bending beam strengths were around 2.8 MPa, 2.4 MPa, 1.1 MPa, and 3.56 MPa, 2.5 MPa, 0.9 MPa for RCGPC using RCA and RAP, respectively. XRD and FTIR analysis also proved the formation of the geopolymer compounds. Similar concrete mixtures using OPC containing RCA and RAP were also tested. The tensile strengths of those mixtures were also compared with the geopolymer mixtures. The results showed that roller-compacted geopolymer concrete using RCA and RAP performed better than similar mixtures using Portland cement concrete in terms of tensile properties. This also proved that geopolymer binder created better bonding with recycled aggregates (RCA) and reclaimed asphalt pavement (RAP) than OPC binder. It is believed that the developed RCA and RAP based roller-compacted geopolymer concrete could be used as an alternative material for pavement construction.