Comparative Experimental Study for Soil Stabilization by Alkali-Activated Slag and Ordinary Portland Cement

Sandy soils which could be found across the vast area in the southern Caspian Sea and other coastal areas in Iran, due to their unfavorable bearing capacity could be the reason for many disasters in geotechnical applications. Ordinary Portland cement (OPC) is commonly used as a cementitious binder for soil stabilization due to its high strength performance. However, OPC production is one of the world’s most energy-intensive and expensive industrial processes; contributing up to 7% of the world’s total CO2 emissions. By developing greener alternatives to OPC, geotechnical applications can benefit more environmentally and financially sustainable binders in long-term. Alkali -activated slag (AAS) has been introduced as a potential alternative to OPC. In the current study, ground granulated blast slag (GGBS) is used as a raw material and combination of sodium silicate and sodium hydroxide as alkali activator for producing binder. The aim of this paper is to present an experimental work in utilizing AAS for soil stabilization to enhance geotechnical properties of poorly graded sandy soil and comparing this binder with stabilized soil by OPC. The effect of curing time (14, 28, and 90 days) and binder percentages (5, 7, and 9 wt. % of dry soil) are investigated. UCS and SEM/EDX tests are carried out in this research to evaluate the mechanical and morphological properties of stabilized soil. Results of this study demonstrate that the used AAS has a great potential for stabilizing poorly graded sandy soils compared to OPC.

Keywords:

Soil Stabilization , Unconfined Compressive Strength (UCS) , Alkali Activated Slag (AAS) , Ordinary Portland cement (OPC).