Strength evaluation of reclaimed asphalt pavement (RAP) stabilized by fly ash, calcium carbide residue and slag geopolymer in pavement applications

In this study, Fly Ash (FA), Calcium Carbide Residue (CCR) and Slag (S) were used as precursors for the geopolymerization of stabilized Reclaimed Asphalt Pavement (RAP) as a sustainable pavement material. Unconfined Compression Strength (UCS) test is used as an indicator to evaluate the mechanical their strength development and are compared with the minimum 7-days UCS requirement specified by the national road authorities in Thailand. The results show that RAP can be used as a pavement base/subbase materials, when treated with 10%S geopolymer as well as with a combination of 5�+5%S and/or 5�R+5%S geopolymers where their UCS of the mixtures meet the minimum strength requirement. The high rate strength development of the S-based geopolymer may attributed to the chemical reaction between the high amount of Silica and Calcium of S and alkaline activator resulted in C-A-S-H products. Furthermore, the geopolymerization products (N-A-S-H gel) may occurred and co-existed with C-A-S-H gel when the combination of FA with S and CCR with S used as a precursor. Therefore, the strength gained was noted. The outcomes of this research are advantageous as a guideline of using recycled and wasted materials in road construction leading to economic and environmental benefits.