Feasibility of Reclaimed Asphalt Pavement Geopolymer Concrete as a Pavement Construction Material

Concern exists regarding the performance of concrete containing a higher percentage of recycled aggregates. There is an ongoing effort to improve the strength and durability characteristics of such concrete in various ways. As part of that effort, this study investigated the laboratory performance of geopolymer concrete containing a higher dosage of reclaimed asphalt pavement (RAP) as a pavement construction material. A series of laboratory investigations were performed to evaluate the mechanical, durability, and morphological characteristics of RAP-geopolymer concrete (GPC). The mechanical properties of RAP-geopolymer concrete were also compared with RAP-Portland cement concrete (PCC) produced using ordinary Portland cement (OPC). Results indicated that RAP-geopolymer concrete exhibited higher compressive, flexural, split tensile strength as compared to RAP-cement concrete. Further, RAP-geopolymer concrete revealed satisfactory results in terms of durability regarding wet-dry cycles and water absorption (sorptivity). Morphological and microstructural investigation using scanning electron microscopy (SEM), X-Ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR) also discovered the formation of geopolymer compounds in RAP-geopolymer concrete which explains the better mechanical and durability properties of such concrete mixtures.