ANALISIS PENGARUH VARIASI KADAR FLY ASH DAN SEMEN TERHADAP SIFAT MEKANIS TANAH EKSPANSIF

Abstract

Expansive soils are classified as problematic soils that cause engineering problems in structures and roads. High shrinkage-deflection potential and low free compressive strength cause structural failure and financial loss. This study aims to understand the characteristics of expansive soil after stabilization method by adding varying percentage of fly ash "FA" and portland cement "C" is evaluated to improve the mechanical properties of expansive soil. The percentage addition of FA used in this study was 5%, 10%, and 15%, while the percentage addition of cement used was 2% and 5%. The percentages of both stabilizers were added based on the dry soil mass ratio. The results showed that fly ash and Portland cement can significantly increase expansive soil's compressive strength and shear strength and reduce natural soil's development potential. The increase in free compressive strength and void shear strength was proportional to the duration of curing time. The optimum percentage to increase the free compressive strength and chiral shear strength occurred in a mixture of 15%FA and 5%C with a curing time duration of 14 days. In addition, the variation of mixtures between natural soil and stabilizers generally succeeded in reducing the expansion index value with the optimal variation in the mixture of 5%FA without cement addition with a curing time duration of 0 days reducing the expansion index value by 72.4%. The mixture of natural soil and 15%FA with the addition of 5% C at a curing time duration of 7 days reduced the expansion index value by 68.98%.