Effects of Temperature and Clay on Hydration Behavior of Mortar: A Study Through Ultrasound Technique

This paper aims to characterize the effects of natural clay additions in mortar mixes in different concentrations and under different curing temperatures on setting and hardening of cement mortar. For this purpose, characterization technique based on reflection of ultrasounds was used. Using this technique, the attenuation coefficient and modulus of reflection coefficient are measured to characterize the early age hydration behavior of tested cement-mortars. Ultrasound P-waves were generated using a 1 MHz central frequency immersion transducer and mortar samples were prepared with Portland cement. The results show that increasing the curing temperature accelerates the setting of the mortar. In addition, the incorporation of natural clay to the mortar mix in different concentrations results in retardations in the end of setting time of mortar. Also, the results confirmed that the hardening behavior of the mortar subjected to high curing temperature and mixed with the different natural clay additions is not linear.