Influence of Wet-Dry Cycles on Compressive Strength of Calcium Carbide Residue-Fly Ash Stabilized Clay

This article studies the durability of the calcium carbide residue (CCR) and fly ash (FA) stabilized silty clay against wetting and drying cycles to ascertain its performance in pavement applications. The durability test on the CCR-FA stabilized clay samples compacted on dry and wet sides of optimum was performed according to the ASTM. The mixture of CCR and FA can be used for soil stabilization instead of ordinary portland cement. The suitable ingredient of CCR, FA, and clay results in a moderately high strength and durability geomaterial. The durability against wetting and drying (w-d) cycles of the CCR stabilized clay is considered low according to the recommendations of the American Concrete Institute and the U.S. Army Corps of Engineers and is not accepted as a pavement material. The input FA at optimal content reacts with the excess Ca(OH)2 from the CCR, and hence a significant improvement of the strength and durability. The optimal FA content is found at about 20%. The strength analysis shows that the durability is directly related to the unsoaked strength (prior to the w-d cycles). Consequently, a relationship between the w-d cycle strength and unsoaked strength is proposed. It is useful for quick determination of unsoaked strength during mix design to attain the target strength at the design service life.