Using High Reactivity Attapulgite for Stabilizing Collapsible Gypseous Soil

Abstract

The presence of gypsum in soil has a high effect on the mechanical and physical properties of soil. This effect depends fundamentally on the type and quantity of gypsum existent in the soil. The present study attempts to improve the physical and mechanical properties of gypseous soil using a new type of pozzolanic material discovered as a pozzolanic material from attapulgite clay. It is called “High Reactivity Attapulgite” HRA. The objective of this study is to investigate the ability of this material to be a moderate stabilizer material used for treating soil. The soil was obtained from one location at depth 1 m with 28% gypsum content. High Reactivity Attapulgite (HRA) was used as a replacement with soil in different percentage (5%, 10%, 20%, and 40%). Experimental tests included Atterberg limits, modified compaction, strength, unconfined compression and consolidation. Then all the tests were conducted on specimens with HRA content that was varied in the range 5-40%. The results showed the important effect of HRA on gypseous soil, as was seen from the reduction in the collapse potential by about 13-90%, and the increase in the unconfined compressive strength from 88 kPa to 271 kPa upon the addition of HRA by 5-40%.