The results of unconfined compression and oedometer compression tests confirmed the existence of optimum mixing clay water content for economical and efficient mixing of cement and clay for deep mixing method (DMM) application. A concept supporting the existence of optimum mixing clay water content is presented, and a schematic diagram idealizing the clay-water-air-cement interactions is illustrated. The optimum mixing clay water content (Cw,opt) is defined as the total clay water content of the clay-water-cement mixture that would yield the highest possible improvement in strength of cured cement-admixed clay. Based on the test results presented, the Cw,opt would fall near the liquid limit of the base clay. Significantly, at this optimum mixing water content, only 10% cement by weight is needed instead of the corresponding 17 % in the conventional method of mixing, with consequent 40 % reduction of cement content and cost.

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