Enhance the rheological and mechanical properties of clayey materials by adding starches

Several native and derivate starches have been studied in association with two types of clayey materials: quarry fines and kaolinite. The mixes were manufactured with a constant starch/clayey material ratio of 1%. The optimal water content has been determinate by the flow test. The rheological and mechanical tests have shown a significant effect of starch on the properties of mixes. In the rheological part, most starches have induced an increase up to four times the thixotropic index for quarry fines, while a decrease of this parameter has been observed with the kaolinite. From a mechanical point of view, all starches increase mechanical strengths whatever the clayey material.