Strength development and lime consumption progress relationship in lime stabilized bentonite samples: Fid-Bau Portal

Strength development and lime consumption progress relationship in lime stabilized bentonite samples

Gueridi, Fatima / Derriche, Zohra

Abstract Although soil-lime treatment has been successfully used for a long time, the mechanisms behind the clay soil-lime reaction remain insufficiently understood until today. Improvements provoked by lime addition are observed immediately on the soil texture that passes from a plastic state to a coarser state. Strength gain, which corresponds to the advancement of the pozzolanic reaction, develops as a long-time process. Strength development of lime stabilized clays has been extensively studied but investigations on lime consumption progress are scarce. Experimental results related to lime consumption progress, strength development, and pH evolution over time in lime-treated bentonite samples are used in this contribution to shed some light on the clay-lime reaction mechanisms. Results obtained indicate that the short-term and long-term reactions take place sequentially. The short-term reaction occurs at constant pH, lasts about 3 days producing only a limited strength gain. The long-term pozzolanic reaction develops much of the strength gain, which occurs in line with lime consumption and is accompanied by pH value decrease starting from the pH corresponding to the initial consumption of lime (12.65) going down to 11.5 after a long curing time. Based on the results obtained, a strength and lime consumption relationship similar to that that has been shown to exist between strength and the volume of the reaction products formed in cements is defined. XRD results do not show cementing minerals’ peaks but pozzolanic reaction occurrence is evidenced by decrease of the peaks of montmorillonite and silica-based compounds of the studied bentonite.