Stabilization of a swelling soil using three different chemical additives

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Abstract. An expansive soil expands when water is added, and shrinks when it dries out. On construction sites, expansive soils can pose geotechnical engineering challenges. More financial loss is caused by expansive soil damage than by floods, hurricanes, tornadoes, and earthquakes combined. The aim of this study is to analyze the effect of stabilization of an expansive soil using three different chemical additives, in this case: white cement and nano-silica as admixture, waste granite dust, and a new liquid polymer soil stabilizer (i.e. liquid granite). This study investigated the effect of these stabilizing agents on the variation of soil consistency, linear shrinkage, and soil swelling behaviour. Three groups of tests were carried out as part of the experimental program. As part of the first group, tests were performed on expansive soil reinforced with 2%, 4%, 8%, and 10% of white cement combined with 2% of nano-silica. Another group of tests consisted of samples mixed with different percentages of granite powder (5%, 10%, 15%, and 20%). In the third group, liquid granite as a soil stabilizer was blended with soil specimens at various concentrations (1%, 2%, 3%, and 4%). For all admixtures, the results showed a marked improvement in soil consistency, an important decrease in linear shrinkage, and a considerable reduction on the expansion index. Compared with the original bentonite clay, the swelling behaviour (expansion index) was reduced considerably by adding these three different chemical additives. Moreover, a correlation between the expansion index and the dosage of the different stabilizers was proposed.