LAUSR

The purpose of this study was evaluation of magnitude and time rate of swelling pressure due to the presence of gypsum in clayey soils stabilized with lime. 3,5 and 10 % of lime by dry weight and 0, 5 and 10 % of gypsum (calcium sulphate) were added to a bentonite. Then uncured and cured as compacted samples of mixtures were tested one dimensionally for constant volume swelling pressure measurement. The results showed that only samples treated with 3 and 5% lime without curing and with 7 days of curing showed initial increase in the magnitude of swelling pressure due to the presence of gypsum as compared with untreated bentonite or with bentonite treated with lime only. In fact samples with higher content of lime and gypsum which cured for 7 days or more actually showed lower swelling pressure compared with untreated samples.