Sustainable flexible pavement base stabilization with pozzolanic materials incorporating sodium hydroxide and asphalt emulsion

Abstract

For the sustainable viewpoint in the road construction sector, fly ash (FA) as one of the potential industrial by-products for recycling would be on finding its alternative utilization. In this study, FA and hydrated lime (HL) as the pozzolanic materials were improved using the sodium hydroxide in a solid form (NaOH) and the asphalt emulsion (AE) for being a road base stabilizer. Effects of additional NaOH and AE into the FA-HL binder were investigated through mechanical properties, structural formation, and durability. Study results revealed that using NaOH increased the compressive strength but decreased the workability of the FA-HL binder. Since NaOH stimulated the FA-HL binder to fabricate cementitious products as N-A-S-H gels. The addition of AE in the FA-HL binder with NaOH could prolong the hardening process, indicating the retardation on the structural formation of pozzolanic reaction and polymerization. Besides, NaOH and AE as the FA-HL treated base material additives had an insignificant effect on the compaction characteristic. Using NaOH and AE into the FA-HL treated base material could develop proficient bearing strength and durability in the wet-dry deterioration. According to these experiments, adding NaOH and AE into the FA-HL binder for road base stabilization can reach the minimum criteria of the flexible pavement base. Eventually, the pozzolanic materials essentially require the extra additives for a new road base stabilization based on eco-friendliness.