Engineering and environmental aspects of cutback asphalt (MC-70) stabilization of swelling and collapsible soils: A. S. Al-Homoud, T. Khedaywi & A. M. Al-Ajlouni, Environmental & Engineering Geoscience, 1(4), 1995, pp 497–506

Abstract

The basic objective of this research was to investigate the effectiveness of Cutback Asphalt (MC-70) as a soil stabilizing agent. For this purpose, four different soils from Northern Jordan, which exhibit certain engineering problems, such as swelling and collapsibility, were selected. The collapsible soil samples were obtained from sites in Mafraq (Soil A) and within the Jordan University of Science and Technology Campus (Soil B). The swelling soil samples were obtained from Irbid (Soil C) and Ramtha (Soil D). To conduct this work, soil-Cutback Asphalt (MC-70) mixtures were prepared at 3 percent, 5 percent, 7 percent and 10 percent Cutback Asphalt (MC-70) by dry weight of soil. Both natural and Cutback Asphalt (MC-70) treated soils were subjected to similar laboratory tests to observe the influence of Cutback Asphalt (MC-70) on swelling and collapse potential. The test results showed that Cutback Asphalt (MC-70) is effective in stabilizing the tested soils. Upon mixing with soils, bituminous materials act as a binding agent between soil particles. Additionally, test results showed that Cutback Asphalt (MC-70) percentages in excess of 7 percent do not show a substantial reduction in swelling and collapsibility potentials. A general comparison of the effectiveness and economic feasibility of Cutback Asphalt (MC-70) to lime and cement, as stabilizing agents for reduction of swell potential of soils containing a high percentage of fines (e.g., Irbid Soil), showed that Cutback Asphalt (MC-70) causes higher reduction in swell potential than cement and a lower reduction than lime. However, Cutback Asphalt (MC-70) was found to be the least economical agent. On other hand, there are cases where lime or cement can have problems which can be resolved by the use of Cutback Asphalt (MC-70), e.g., the case where complex reactions occur between the lime and salts in the soils where cation exchange, agglomeration and carbonation were unaffected by the addition of lime, and the case of the treatment of sulfate-bearing soils especially in the abundance of water.