Influence Of Curing Heat Time on Silty Clay Laterite Soil Stabilized with a Metakaolin-Bischofite-Alkalinization; Strength and Microstructural Characterization

Abstract

Many researchers have highlighted the significant influence of various parameters, including initial curing conditions, alkaline activator concentration, ingredient composition, and curing temperature duration, on the characteristics and effectiveness of high calcium geopolymer-stabilized soil. However, there is limited research on the effects of different curing temperatures and durations on the stabilized silty clay laterite soil using environmentally friendly low-calcium geopolymers. Therefore, this study aimed to investigate how the duration of curing temperature affects the strength and microstructural characteristics of subgrade soil stabilized with metakaolin-bischofite-alkalinization, a novel additive. The experiment involved applying curing temperatures ranging from 25°C, 40°C, 600C, and 80°C with curing periods of 1, 2, and 3 days for each temperature treatment to assess the reaction kinetics. Each sample was further cured for 7-, 14-, and 28- days at controlled room temperature before testing. The results indicated that curing temperatures significantly enhanced strength even at lower temperatures, such as 25°C. The UCS and E50 showed the most significant improvement when specimens were cured at 60°C for 3 days, leading to a noticeable enhancement compared to untreated soil conditions. Moreover, FE-SEM, EDS, and TGA findings confirmed a compact soil matrix with the presence of magnesium-silicate-hydrate (M-S-H) and sodium-aluminate-silicate-hydrate (N-A-S-H) cementitious gel phases.