Effect of Wetting-Drying and Freezing-Thawing on Performance of Geopolymer-Treated Base: A Comparative Study

Full depth reclamation with cement (FDR-PC) has been widely practiced for rehabilitating deteriorated flexible pavements. However, the utilization of cement in construction activities is unfavorable because of the significant carbon emissions associated with its production. The present research work intended to investigate the viability of fly ash (FA) and ground granulated blast furnace slag (GGBS) based geopolymer binder for stabilization high volume roads, having 30% reclaimed asphalt pavement (RAP). Furthermore, a comparative study was conducted to determine the efficacy of wetting-drying and freezing-thawing test procedures for assessing the durability of such chemically stabilized materials. The testing program was carried out by treating the reclaimed materials initially with cement, ranging from 4% to 8% by weight of the total mix. Following this, full depth reclamation using geopolymer (FDR-GP) experimented with FA: GGBS blends of 80:20, 70:30, 60:40, and 50:50. However, the total binder in each of these mixes was kept constant at 20% by weight of reclaimed asphalt pavement materials. These supplementary cementitious materials (SCM) were alkali-activated using sodium hydroxide (NaOH) of 2 molars (M) concentration. A mixture having 70%FA and 30% GGBS could successfully achieve the target 7-day UCS of 4.95 MPa and experienced a mass loss of merely 3.85% and 4.88% after wet-dry and freeze-thaw cycles, respectively. However, in-depth analysis in terms of retained UCS and mass losses inferred that the freezing and thawing test is more viable for assessing the durability of such chemically stabilized materials as the oven-drying involved in the wetting-drying test leads to false-positive results.