The effect of burnt lime addition on hydration of Ultra-high performance cementitious composites

Abstract

The paper deals with the burnt lime utilization as a source of calcium ions participated during hydration process of ultra-high performance cementitious composites. These type of ultra-high performance cementitious composites are based on the high content of silica fume that together with calcium ions form the binder phase. In the case of ordinary Portland cement, the hydration during induction period supposed to be too slow for dissolution of required amount of calcium ions necessary for the pozzolanic reaction of presented silica fume. The low addition of the lime should be a sufficient calcium source that allow the starting of the pozzolanic reaction before the acceleration period occurs. The calcium ions content from the beginning of the reaction was controlled by an addition of soft-burnt and dead-burnt lime. Its influence was studied in terms of hydration process by isothermal calorimetry. Based on the experimental data, the hydration reaction mechanism was proposed.