General Contractor Practice Exam

Which chemical is commonly used in high heat concrete applications?

1. Accelerator

2. Retarder

3. Hardener

4. Plasticizer

The correct answer is: Retarder

In high heat concrete applications, a retarder is commonly used to extend the setting time of the concrete. This is particularly important when the temperatures are elevated, as high heat can accelerate the curing process. When concrete cures too quickly, it can lead to issues such as cracking and reduced strength. By incorporating a retarder, contractors can ensure that the concrete maintains workability for a longer period, allowing for proper mixing, placement, and finishing. This becomes crucial in hot weather conditions where rapid evaporation can further complicate the curing process. On the other hand, accelerators would generally speed up hardening, which is not desirable in high-heat applications where control over the curing process is needed. Hardeners are typically used to increase the surface hardness but do not directly relate to managing curing time in hot conditions. Plasticizers improve workability and reduce water content but don't specifically address the challenges posed by high heat during curing. Thus, using a retarder is the most effective approach for high heat concrete applications to ensure optimal results.