Properties of soft Bangkok clay stabilized with cement and fly ash geopolymer for deep mixing application
Cherdsak Suksiripattanapong, Ratchanon Sakdinakorn, Sermsak Tiyasangthong, Nattiya Wonglakorn, Chayakrit Phetchuay, Wisitsak Tabyang
Abstract
Deep mixing (DM) is a technique for improving the ground that has been widely used worldwide. Ordinary Portland cement (C) has historically been the most popular binder for DM application; however, utilizing C releases a large carbon footprint. This research investigates the properties of soft Bangkok clay (SC) stabilized with C and high calcium fly ash (FA) geopolymer for high-strength soil–cement columns. The effect of influence parameters on the unconfined compressive strength (UCS) and scanning electron microscope (SEM) properties of SC-C-FA geopolymer specimens was measured. The specimens had initial water contents (w) of 1LL, 1.5LL, and 2LL, FA:C ratios ranged from 100:0–70:30, and sodium silicate:sodium hydroxide ratios (NS:NH) of 50:50, 70:30, and 80:20. The results indicated that the UCS of SC-C-FA geopolymer specimens was found to increase with the increasing C content. Whereas, the UCS decreased with the decreasing NS:NH ratios. The highest 28-day UCS of the specimen was obtained with initial water content of 1.5LL, FA:C ratio of 70:30, and NS:NH ratio of 50:50. The 28-day UCSs of SC-C-FA geopolymer with all initial water contents, C content greater than 5%, and NS:NH ratio of 50:50 passed the minimum UCS requirement for soil–cement columns. Furthermore, the equations for predicting UCS and carbon emissions of SC-C-FA geopolymer are very useful for designing soil–cement columns.