Quantitative study on strength development of earth-based construction prepared by organic clay and high-efficiency soil stabilizer

The earth-based construction with unique advantages in raw material origin, energy conservation and environment protection has attracted growing attention recently. In South China, raw soils which have been used for hundreds of years are mainly organic clays with high water and organic matter contents. This research uses reconstituted organic soil technique for preparing earth-based construction in order to analyze effects of fly ash and organic matter on compressive strength quantitatively. The used cementing material is a high-efficiency stabilizer called CSCN, and organic clay is obtained by mixing humic acid powder (HAP) with raw soil. Compressive strength is measured to investigate the influence of fly ash, and XRD and SEM analysis are used to understand the mechanism of fly ash in stabilized earth with HAP. The hypothetical CSCN content of fly ash and CSCN-consumption content of HAP are proposed by redefining the P&D factors (kfh) and consumption index (OCIfh). Subsequently, the strength-calculation models are proposed, and the deviation between the calculated strength and measured strength is not more than 10%. The changes in the quantity and type of hydration products observed from XRD patterns and SEM photos may explain the mechanism of fly ash in earth-based construction with organic matter.