Concentrated effect of drying agents on mechanical performance of clay soil

Abstract

In modern construction, more and more attention is paid to the roadbed quality. At the same time, in most regions of the Russian Federation there is a shortage of natural building materials of the required quality. In this regard, methods of stabilizing natural clay soils should be developed to satisfy the regulatory documentation.Purpose: The chemical additive effect on mechanical properties of clay soil.Methodology: The proposed method of concentrated effect of drying agents (lime, active fly ash) can potentially improve the mechanical performance of clay soils, i.e., strengthen the soil. Compressive strength testing of clay soil (light powdery loam) includes its treatment in hydrated lime in the amount of 2, 4 and 6 wt.%, hydrated high-calcium fly ash in the amount of 4, 8 and 12 wt.%, and a combination of slaked lime and chemical additives-accelerators (CaCl2, FeSO4, NaOH) in the amount of 0.5 and 1.0 % of the dry soil mass.Research findings: Even small amounts of lime improve the clay soil strength, which exceeds the effect from the fly ash introduction by 194 %. CaCl2 and NaOH additives significantly accelerate the strength gain. The introduction of FeSO4 improves the strength gain kinetics at the first stage (up to 7 days) and further causes a complete destruction of the material structure. The compaction also shows a significant decrease in the tensile strength during the time between the dry agent introduction and compaction.