Pengaruh Penambahan Fly Ash Terhadap Perilaku Teknis Tanah Ekspansif di Daerah Selimau Kabupaten Bulungan

Abstract

Expansive soil is one of the problematic soils for civil engineering construction. The high swelling-shrinkage nature results in deformations that can damage the construction on it, therefore it is necessary to make improvements in expansive  soil. One of the most widely used methods of improving expansive soil is stabilization using chemical additives. In this research using coal waste material (fly ash) as stabilizer from PLTU Sekayan in Kaltara Province, so it can be said as environmentally friendly stabilization. The research objective was to determine changes in engineering behavior of expansive soil through compaction tests and CBR. The test results will be displayed in graphical form, namely by comparing the expansive soil that has not been stabilized (initial conditions) and the expansive soil that has been stabilized with fly ash at mixed variations of 20%, 30% and 40%, and has passed the curing period for 5, 15, and 30 days. From this research, it was found that the addition of a stabilizer (fly ash) could improve its engineering properties, and the optimum results were obtained at the addition of 40% fly ash and after 30 days of curing time. From the compaction test, it was found that the volume weight of dry soil (γ_dry) increased by 14.05% from 1.21 gr/cm³ to 1.38 gr/cm³ and the optimum water content (w_opt) decreased by 38.12% from 31.19% to 19,3%. From CBR testing in the laboratory, there was a very large increase in the value of CBR_Design, namely 2192% from 0.72% to 16.5%