What substance is added to cement to slow its curing process?

The substance added to cement to slow its curing process is referred to as a retarder. Retarders are chemical additives used in concrete mixtures that delay the setting time of the concrete. This is particularly useful in situations where the concrete needs to be transported over a longer distance, during hot weather when the setting time may be affected by high temperatures, or when working with complex pours that require additional time for placement.

By incorporating a retarder, contractors can ensure that the concrete remains workable for a longer period, allowing sufficient time for mixing, transporting, and placing the material before it begins to harden. This controlled delay helps to prevent issues related to premature setting, which can lead to difficulties achieving the desired finish and strength.

In contrast, accelerators speed up the curing process, hardeners are aimed at increasing the strength or hardness of concrete after it has set, and binders generally refer to materials that help to hold other materials together but do not directly influence the curing time of cement.