What affects the weight of normal-weight concrete?

The weight of normal-weight concrete is primarily influenced by the mix design and the type of aggregate used. The mix design determines the proportions of cement, water, and aggregates, which can vary considerably. Aggregate types, whether they are natural or manufactured, also significantly affect the density and therefore the weight of the concrete. For instance, using heavier aggregates such as barite or magnetite can lead to a denser concrete, whereas lighter aggregates like expanded clay or polystyrene can reduce the overall weight.

While the type of cement does play a role in determining concrete's properties, it is the combination of all materials in the mix design and their respective densities that ultimately dictates the weight of the finished product. Other factors such as curing environment and duration, while important for achieving desired strength and durability, have less impact on the inherent weight of the concrete mix itself once it has cured. Therefore, the correct choice underscores the crucial relationship between aggregates and mix composition in defining the weight of normal-weight concrete.