Which of the following factors affects the compressive strength (𝑓′𝑐) of concrete?

The compressive strength of concrete, often denoted as ( f'c ), is significantly influenced by several factors, including the water-cement ratio, aggregate size, and cement type. Each of these elements plays a crucial role in defining the overall strength of the concrete.

The water-cement ratio is particularly critical because it dictates the amount of water available to hydrate the cement particles. Reducing the water-cement ratio generally leads to higher compressive strength, as less water results in a denser and more durable concrete structure. Conversely, a higher water content can lead to increased porosity and reduced strength.

Aggregate size also affects compressive strength. Smaller aggregates can help fill voids between larger particles, leading to a denser concrete mix, whereas excessively large aggregates might create weak points within the mixture. The proper selection of aggregate size ensures a better bond within the concrete matrix.

The type of cement used is another determinant of compressive strength. Different types of cement have varying chemical compositions, which influence the rate of hardening and the ultimate strength achievable in the mix. For example, some cements are formulated for rapid strength gain, while others are designed for durability or resistance to specific environmental challenges.

Considering all these factors, it becomes clear that each