Preparation and Application of Nanoscaled C-S-H as an Accelerator for Cement Hydration

Abstract

In the present work an easy mechanochemical approach was used to prepare the C-S-H seeds out of simple commercial available materials. The preparation method was optimized with regard to achieve the highest acceleration by using statistical analysis of a factorial design of experiments setup (DoE). Isothermal heat flow calorimetry was used to quantify the efficiency of the seeds to accelerate the hydration of ordinary Portland cement (OPC). The setting and hardening behavior of cement pastes containing the seeds was studied by ultrasonic testing and Vicat needle penetration tests. The compressive strength after 12 h could be tripled by the addition of just 0.5 wt% in respect to the cement mass and a significant advance of strength remains for the following 3 days of hydration.