Effect of recycled brick powder on the hydration process of cement paste

Using recycled brick powder (RBP) in blended cement is beneficial to energy saving and emission reduction. The hydration process of blended cement containing RBP is significant for the mechanical property and durability of concrete. The hydration mechanism of blended cement containing recycled brick powder (RBP) has been investigated through hydration heat, hydration degree, and hydration products of the pastes to reveal the effect of RBP on hydration and the reaction mechanism of RBP. The results show that the addition of RBP reduces the heat release during the hydration process, but its nucleation and dilution effects promote cement hydration. The inclusion of RBP also decreases the amount of Ca(OH)(2) in the system. The content of the amorphous phase in the system continuously increases with hydration time, and after 28 days of hydration, the amorphous phase is derived from both cement hydration and the pozzolanic reaction of RBP. Between 28 and 90 days of hydration, the reactivity of RBP significantly increases.