STUDI STABILISASI TANAH LEMPUNG EKSPANSIF DENGAN KOMBINASI PASIR DAN LIMBAH GYPSUM: UPAYA MENINGKATKAN DAYA DUKUNG DAN KEAMANAN INFRASTRUKTUR

Abstract

The agricultural land in Karawang, has seen substantial transformation, with former farmlands repurposed for residential, industrial, and infrastructure development. These areas primarily comprise expansive clay soils, which exhibit high shrinkage, low permeability, and poor bearing capacity. These conditions can potentially lead to structural damage in buildings and roads, posing safety concerns for residents and road users. This research seeks to determine the most effective soil stabilization mixture to enhance expansive clay's load-bearing capacity and shear strength. The stabilization mixtures tested consist of gypsum waste and silica sand in a 1:1 ratio, with concentrations of 2.5%, 5%, and 7.5%. Sand is included to improve the soil's shear strength, while gypsum waste is used for its lime content, which is expected to minimize the shrink-swell behavior of the clay. The method used in this research uses the California Bearing Ratio Soaked and Unsoaked method to determine the soil's bearing capacity conditions during dry conditions and air-saturated conditions such as during the rainy season or areas with high groundwater levels. Apart from CBR testing, laboratory Unconfined Compressive Strength (UCS) testing is also carried out which is used to determine the strength of the soil without lateral pressure. This test is primarily used for cohesive soils, such as clay, in saturated or unsaturated conditions. The findings reveal that increasing the percentage of stabilization materials results in improved outcomes, such as higher shear strength and a reduction in shrink-swell potential. However, the differences in shear strength and shrink-swell reduction between the 5% and 7.5% mixtures were not significantly pronounced, suggesting that both mixtures can be effectively used for soil stabilization.