Activation of clay in cement mortar applying mechanical, chemical and thermal techniques

Different techniques such as mechanical activation, chemical activation and thermal activation have been employed to activate clay used as a cement replacement material. The clay was activated mechanically by grinding it to 250, 360 and 420 m(2)/kg Blaine surface areas; chemically by mixing clay with two alkalis (potassium hydroxide (KOH) and sodium hydroxide (NaOH)) with different concentrations and thermally by keeping the mortar samples at 20, 40 and 60 degrees C. Samples were tested for compressive strength at the ages of 3, 7 and 28 days. All these methods were found to enhance the reactivity of clay. It was found that an increase in the fineness of clay increased the strength development and the fineness should be greater than that of cement in order to enhance the performance.