Admixtures

Accelerating admixtures are very commonly used in the winter months in all concrete applications. In cold weather the set times of concrete are delayed, which results in additional placing, finishing and curing costs and can delay the construction schedule. Using accelerating admixtures can offset the effect of cold weather and generate higher earlier strengths. Accelerating admixtures can be used in any mix designs. The main aspect to consider when using in combination with High-Range Water Reducers (HRWR) is the effect it can have on the air content and the dosage of air entraining admixture. Furthermore, as Accelerators are typically used at high dosage rates, the water content of the mix should be adjusted accordingly. Another point to consider when using Calcium Chloride based accelerators is corrosion. Typically mixes containing HRWR are used in structural applications, the use of calcium chloride at high dosages may initiate corrosion and lead to structural damage. In these cases, the use of a non-chloride accelerator is recommended. In rare occasions depending on the chemical composition of the accelerator, and often in combination with the use of fly ash, the use of accelerator can lead to discoloration of concrete.