THE PERFORMANCE OF SOIL STABILIZATION WITH MARBLE ASH IN PHYSICAL MODEL TESTS IN THE LABORATORY

Clay is one type of soil frequently used as a subgrade.Clay soils as subgrade soils with poor performance are found in expansive, soft, and very soft clays.The clay soils have low CBR value and low bearing capacity.Problematic soil characteristics can interfere with the performance of the road construction above it.Inadequate subgrade soils require improvement with soil stabilization to improve characteristic properties.Therefore, an experiment was conducted by adding marble ash to clay soil to improve soil characteristics and increase the CBR value.The research method was conducted through field testing, laboratory testing, and physical model testing in a test box.This research utilized the addition of marble ash content of 3%, 6%, 9%, and 12%, which were mixed with clay soil in thicknesses of 10 cm, 20 cm, and 30 cm.The results showed that the increase in CBR value for 6-12% marble ash is not much different.The average increase in CBR for 6% marble ash is 5.11 times, for 9% marble ash is 5.28 times, and for 12% marble ash is 5.70 times, while for 3% marble ash, it is only around 2.99 times.The minimum CBR value of 5% for subgrade soil was obtained at 6% marble ash content with a soil thickness of about 20-30 cm.CBR values above 5% can be used as a subgrade for road construction.