ANALYSIS OF THE CHARACTERISTICS OF DIFFERENT SOIL TYPES STABILIZED WITH CASSAVA STARCH

Nimlyat Pontip Stephen

Department of Architecture, University of Jos, Nigeria

E-mail: pontipn@unijos.edu.ng

ABSTRACT

Soil can be stabilized using several kinds of chemical and other stabilizing agents. The possibilities of utilizing cassava starch as a soil stabilizing agent and the response of five different soil types are studied in this paper. Compaction characteristics, penetration resistance, abrasion resistance, swelling potentials and compression strength of Sandy, Clayey, Humus, Laterite and Gravelly soils are analyzed. This analysis was carried out at 0, 2.5, 5, 7.5, 10, 15 and 20 percent stabilization levels by weight. The soil samples were treated with cassava starch paste at various levels and compacted in CBR and Proctor moulds using heavy and light compaction methods respectively. It is observed that the adhesive property of cooked cassava starch has a binding effect on the particles of the five soils studied. Also, a level of stability, which is soil dependent, is achieved. Laterite soil recorded a difference in CBR values of about 27 percent between the 0 percent and 7.5 percent stabilization levels with better penetration resistance. Stabilized clay offered the best resistance to abrasion that improved with increase in starch content. The other soil types were also observed to be relatively poor in resistance to water absorption. Increasing the starch content and hydration period, a compressive strength of 3.55N/mm² at the 20 percent stabilization level was established for the laterite soil at 28 days hydration period. This result when compared to the strength of 0.5N/mmn² at 0 percent level is an indication of improvement in compressive strength.