Role of Gypsum Content on the Long-Term Performance of Lime-Stabilised Soil

Abstract

The role of gypsum level on the long-term strength and expansion of soil stabilised with different lime contents is not well understood. This research, therefore, studied the effect of varying gypsum concentrations of 0, 3, 6, and 9 wt% (equivalent to the sulfate contents of 0, 1.4, 2.8, and 4.2%, respectively) on the performance of sulfate soil stabilised with two lime levels (4 and 6 wt%). This was carried out to establish the threshold level of gypsum/lime (G/L) at which the increase in G/L ratio does not affect the performance of lime-stabilised sulfate soil. Both unconfined compressive strength (UCS) and expansion, along with the derivative thermogravimetric (DTG) analysis, were adopted to accomplish the present objective. Accordingly, the result indicated that the strength and expansion were proportional to the lime and sulfate content, of which a G/L ratio of 1.5 was the optimum case scenario for UCS, and at the same time, the worst-case scenario for expansion. This discovery is vital, as it is anticipated to serve as a benchmark for future research related to the design of effective binders for suppressing the sulfate-induced expansion in lime-stabilised gypseous soil.

Behavior of Natural Pozzolana-Lime-stabilized Clayey Soils Artificially Contaminated by Sulfates

“…In fact, expansive clay containing montmorillonite and illite as clay minerals shows a considerable volume change upon small variations in water content considering the environmental changes (Batool et al, 2021;Hamza et al, 2022). Recently, Ebailila et al (2022) have studied the effective role of different gypsum contents on the long-term performance of limestabilized kaolin soil. They have found that the addition of lime to kaolin soil in the absence of gypsum reduced the expansion through both changing of fabric soil and the development of pozzolanic reactions with the curing time.…”

Soil Stabilisation by Analytical Techniques

“…Bragg's law explains the characterising and measuring the positions of the reflections, crystals and their structures. Studies on the effect of stabilised soil by XRD and SEM have been done for cement-stabilised compacted tills reinforced with steel slag and slaked lime [6], lime-silica fume and lime-ground granulated blast furnace slag [7], calcium carbide residue and flyash in soil stabilisation [8], fly-ash geopolymer [9], geopolymer based on glass powder and calcium carbide [10], fine Ground Tile Waste [11] and industrial By-Products and Biochars [12].…”

Strength Improvement Using Polypropylene Fiber as Reinforcement in Natural Pozzolana-lime-stabilized Expansive Clayey Soil Artificially Contaminated by Sulfates

“…Recently, Ebailila et al [32] studied the effective role of different gypsum contents on the long-term performance of lime-stabilized kaolin soil. They found that the addition of lime into the kaolin soil sample in the absence of gypsum increased the strength and reduced the expansion through both changing of fabric soil, and the development of pozzolanic reactions with the curing time.…”