Effect of Sand Addition Techniques on the Characteristics of Expansive Clays: A Laboratory Study

Nowadays many measures have been practiced to overcome the problems posed by swelling soils. One of the methods is to modify the macro structure of expansive clays by adding non-expansive materials. A laboratory investigation to reduce the swelling properties of the expansive soils found at Gunung Bentar - Probolinggo is reported in this paper. Three different techniques were studied, e.g. sand layer, sand-soil mixture, and sand column, as alternative methods to improve the swelling characteristics of compacted expansive clays. Each soil samples with various proportion of sand are compacted statically, and then performing zero swell test by using load ring, and wetting process under controlled water inflow instead of inundate the samples. The results of this study indicated that sand column is the most effective techniques in reducing the value of swelling pressure. However the other two techniques were also found to be effective in reducing the swelling behavior of soils to various degrees as discussed in this paper.