Compaction delay characteristics of clay with cement kiln dust

Abstract

The study investigates the influence of compaction delay on some engineering properties of Philadelphian clay–cement kiln dust mix. The characteristics of the soil investigated were the unconfined compressive strength, California bearing ratio (CBR) and swell potential. It was observed that adding cement kiln dust to the Philadelphian clay significantly improved the aforementioned properties. The Student's t-test conducted with alpha equal to 0·05 and 0·005 chosen as significant and highly significant levels in this study has shown that there was no significant difference in unconfined compressive strength, CBR or swell potential of most Philadelphian clay soil samples compacted for between 1 h and 3 h. However, for samples compacted for between 1 h and 72 h delay there were significant statistical differences in the value of the measured characteristics. The results of the Student's t-test mean that, for the Philadelphian clay, compaction before 3 h of mixing yields maximum benefits. Delay up to 72 h results in significant loss of strength properties. Therefore prior arrangements should be made for compaction before mixing, to the extent possible.