Styrene–butadiene latex modified calcium aluminate cement mortar

This paper investigates properties of calcium aluminate cement (CAC) mortar modified with the styrene–butadiene-rubber (SBR) latex. This material may be advantageously applied as a rapid repair mortar. Mortar specimens were prepared with constant water-to-cement mass ratio; polymer solid content of latex was varied from 0% to 9%, and Li2CO3 was investigated as an accelerator. Specimens were treated at different curing conditions: 1, 7 days and transformation of metastable hydration products at 70 °C. The heat of hydration evolution of mortar specimens was measured by means of a self adopted isoperibol calorimeter. The measurement results indicate that SBR latex improves workability of fresh state mortar and retards nucleation and growth of hydration products. Due to polymer coagulation process and co-matrix formation permeability, stiffness and compressive strength decrease while adhesion strength to old concrete substrate, and flexural strength increase with amount of added latex.