A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering at the Asian Institute of Technology, Bangkok, Thailand.

Thesis (M.Eng.) - Asian Institute of Technology, 1968

This thesis presents a preliminary evaluation of using rice hull ash, in conjunction with lime, to stabilize two clayey soils from the deltaic regions of Thailand and the Philippines. Effects of soil properties, amount of lime-ash admixture, ratio of lime to ash, curing time and artificial weathering test (wet-dry cycles)on the strength development of the stabilized soils are reported. Results showed that the response to lime-ash stabilization of the two clayey soils studied, viz. Bangkok Clay (TH)and Maligaya Clay (PH),is promising, and could be considered feasible. There are indications that factors affecting soil-lime and/or soil-lime-fly ash, and soil-lime rice hull ash stabilization are similar, all these stabilized systems appear to behave in a likely manner in modifying the physicochemical characteristics of clayey soils. The minimum amount of lime (with rice hull ash)required, to develop a 7-day immersed unconfined compressive strength of 150 .lb per sq in. or greater, ranges from 3 to 5 per cent, which is considerably lower than that needed in lime (alone) stabilization to produce equivalent strength values. Longer curing period was found to be beneficial to strength development of lime-rice hull ash stabilized soil.