Evaluating the shear strength of agar gum-treated gypseous soil

Abstract

Gypseous soil is strong in its dry state but has real problems when exposed to water, and this requires an effort to improve it and reduce these problems. Soil chemical improvement is a well-known method and leads to environmental problems related to the emission of greenhouse gases and the impossibility of recycling the improved soil in the future. This encouraged the creation of alternatives to stabilizers with a large carbon footprint. Biopolymers are environmentally friendly materials because of their low carbon footprint, resulting in the creation of improved and sustainable geo-structures. Recently introduced as soil improvement materials, they provide significant reinforcement and in lower quantities than conventional binders such as cement. Agar biopolymer was used to analyze the strengthening properties of gypsum soil. Four gypsum contents were used for soil, which are 8, 25, 45 and 59%, agar content by adding (1, 2, 3)%, The curing time for the prepared samples is 14 days before the tests and obtaining the results. The results showed that the resistance of gypsum- agar mixtures was significantly increased even under water saturated conditions compared to pure soil. The value of (Φ) increased by 24.4% and 32.33% for the soil samples improved by 3% agar in the dry and wet conditions, respectively, while the percentage increase in the cohesion (C) of the improved gypsum soil increased by 67.89% and 45.95% for the dry and wet samples respectively.