Effects of chloride and chloride-free accelerators combined with typical admixtures on the early-age cracking risk of concrete repair slabs

Accelerators are commonly added to concrete mixtures used for concrete repair slabs due to high early strength requirements. This study compared the effects of a calcium chloride-based accelerator and a calcium nitrate-based accelerator in rapid strength concrete mixtures on the early age cracking potential of concrete repair slabs. The results showed more shrinkage, higher restraint stresses, and higher strength for the calcium nitrate-based accelerator mixture. HIPERPAV simulated a lower cracking risk for the calcium nitrate-based accelerator mixture during evening and nighttime placements. Calorimetry, free shrinkage, and rigid cracking frame testing were used with the modeling software to observe trends in these mixtures.