EFFECT OF WET-DRY CONDITION ON COMPRESSIVE STRENGTH OF SOIL IMPROVEMENT WITH CEMENT AND FLY ASH-BASED GEOPOLYMER

Abstract

At present, Ordinary Portland Cement has been widely used to improve the soil for highway base course. However, cement manufacturing process impacted on the environment. Geopolymer was chosen to replace the Ordinary Portland Cement for soil improvement in this research. This research was aimed to study the effect of wet-dry condition on unconfined compressive strength (UCS) of soil stabilized with Portland cement and fly ash-based geopolymer. Percentage of cement was 5 7 9 and 11 by mass and percentage of fly ash was 10 20 and 30 by mass. NaOH solution of 10 molar and various mix design at different fly ash/akali activator ratio and Na₂SiO₃/NaOH ratio were used to preparation specimens and cured for 2 7 and 28 days at room temperature. Each mixture was tested for UCS in accordant to the soil cement standard from the Portland Cement Association was used to perform wet-dry condition test. Wet-dry condition test was divided into 2 sets. The first set was used to conduct the UC test after through the process and the second set was determined the durability of the specimens. The results, revealed that the compressive strength of soil cement tended to decrease after processing and the mass loss percentage was 11.06. The unconfined compressive strength (UCS) of soil geopolymer tended to increase after the wet and dry condition and the mass loss percentage was 6.80. It was concluded that soil geopolymer exhibited the performance in withstanding the wet and dry condition better than soil cement.