What is a benefit of using Portland cement in concrete?

Using Portland cement in concrete is beneficial primarily because it enhances the bonding with aggregates. Portland cement serves as a binder that facilitates strong adhesion between the individual particles of aggregates, leading to a cohesive and durable concrete mixture. When mixed with water, Portland cement undergoes a chemical reaction called hydration, which forms a crystalline structure that effectively fills the voids in aggregate materials. This strong bonding helps ensure that the concrete can withstand various stresses and loads while maintaining its integrity over time.

The other options, while they may relate to concrete properties in various contexts, do not directly capture the primary benefit offered by Portland cement. For instance, water retention is not a property increased by Portland cement; rather, proper mix design and aggregate choice impact that. Similarly, while some formulations can result in lightweight concrete, standard Portland cement does not inherently reduce the weight of concrete—the density is largely influenced by aggregate type and proportions. Environmental considerations also depend heavily on the sourcing and production practices of the cement and concrete mix rather than being an intrinsic benefit of Portland cement itself.