Properties of Two Model Soils Stabilized with Different Blends and Contents of GGBS, MgO, Lime, and PC

TLDR

The study compares GGBS–MgO blends to GGBS–lime and Portland cement for soil stabilization to improve technical performance. The authors evaluated stabilized soils by measuring unconfined compressive strength, permeability, and conducting XRD and SEM analyses while varying GGBS:MgO ratio, binder content, soil type, and curing time. GGBS–MgO blends achieved up to four times higher 28‑day UCS than Portland cement, with optimal MgO content of 5–20 % and produced hydrotalcite during hydration, while overall hydration products resembled those of PC.

Abstract

This paper addresses the use of ground granulated blast furnace slag (GGBS) and reactive magnesia (MgO) blends for soil stabilization, comparing them with GGBS-lime blends and Portland cement (PC) for enhanced technical performance. A range of tests were conducted to investigate the properties of stabilized soils, including unconfined compressive strength (UCS), permeability, and microstructural analyses by using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The influence of GGBS:MgO ratio, binder content, soil type, and curing period were addressed. The UCS results revealed that GGBS-MgO was more efficient than GGBS-lime as a binder for soil stabilization, with an optimum MgO content in the range of 5–20% of the blends content, varying with binder content and curing age. The 28-day UCS values of the optimum GGBS-MgO mixes were up to almost four times higher than that of corresponding PC mixes. The microstructural analyses showed the hydrotalcite was produced during the GGBS hydration activated by MgO, although the main hydration products of the GGBS-MgO stabilized soils were similar to those of PC.