Abstract

Soil with low bearing capacity and problems such as expansive soil are found in the Grobogan Regency area. Expansive soil is soil that is easy to expand and shrink due to the influence of water. In the rainy season the soil absorbs a lot of water so that its volume increases, while in the dry season the water decreases so that the volume decreases. Expansive soils are characterized by large clay content and high soil plasticity index. The highway building which is located on this expansive land is never stable because the road surface will be bumpy, rise in the rainy season and fall in the dry season because the subgrade of the flower road shrinks due to the influence of water content. One way to reduce the swelling and shrinkage of this soil is by using the stabilization method so that it is carrying capacity increases and shrinkage swelling decreases. In this study, stabilization was carried out by adding 6% lime, 2% rice husk ash, 4, 6 and 8% cement by weight with a curing time of 7 and 14 days. From the results of the CBR test there was a significant increase where in the original soil the CBR = 4.3% increased to 37.63% with the addition of 8% cement with a curing time of 14 days. With stabilization of swelling shrinkage (swelling) of the soil is also significantly reduced where the original soil = 16.19% while with cement stabilization 8% it decreases to = 3.12%, this means that the rate of swelling and shrinkage of the soil becomes small. With an increase in the CBR value, it means that the carrying capacity of the soil also increases so that the road becomes stable and not bumpy.