THE EFFECT OF GYPSUM (CaSO4) ON THE VALUE OF COHESION AND ANGLE OF FRICTION USING DIRECT SHEAR STRENGTH TEST Iswandaru, Rully Nurhasan R, Eka Adhitya K.
Universitas Islam Bandung
Abstract
Clay soil is a type of soil that has the characteristics of large shrinkage, this makes clay an unfavorable material in a construction work. Low bearing capacity can lead to instability of a building foundation erected on clay soil and the swelling and shrinkage properties of clay can cause cracks in highway pavements, also rupture or breakage on the ground floor of the dam. In the construction of civil buildings, the cohesion and shear strength of the subgrade have an effect on the planning of a building, so soil stabilization can be carried out before the soil is used. One of the efforts to improve soil stabilization is mixing soil with certain materials in order to improve the technical properties of the soil to meet certain requirements by increasing soil parameters such as density, cohesion, and shear strength. The soil stabilization process includes mixing with gypsum material (CaSO4) to obtain the desired gradation so that the soil properties become better with calcium levels that bind organic matter to clay and also absorb more water which is very useful for strengthening soil. The research was conducted by testing the direct shear strength of the soil (Direct Shear Test) by adding different percentages of Gypsum (CaSO4) ranging from 5% - 10%. The effect of the addition of gypsum on the cohesion value and the optimum internal friction angle occurred in the addition of 7% lime with a value of 0.018 MPa and 24.93o.
