Compressive Strength of Marginal Lateritic Soil Stabilized

Abstract—This research investigated compressive strength and microstructure of marginal lateritic soil stabilized with bottom ash geopolymer as a pavement material. The marginal lateritic soil (MLS) was obtained from a borrow pit in Chaiyaphum Province. Bottom ash (BA) was obtained from the Mae Moh power plant of the Electricity Generating Authority of Lampang Province. This research used the MLS:BA ratios of 70:30, 50:50 and 30:70 and Na2SiO3:NaOH ratios were 0:100, 10:90, 30:70, 50:50, 70:30 and 80:20. The test results showed that the Na2SiO3:NaOH ratios do not affect the unit weight of marginal lateritic soil stabilized with bottom ash geopolymer. The 7-day compressive strength of marginal lateritic soil stabilized with bottom ash geopolymer increases with the increase in Na2SiO3:NaOH ratio (higher Na2SiO3 content) because silica from Na2SiO3 reacts with silica and alumina from bottom ash resulting in geopolymer gel or sodium aluminosilicate hydrate (N-A-S-H). All 7-day UCS values are greater than the minimum strength requirement for UCS of 689 kPa specified by the Department of Highways, Thailand.