What characteristic of aggregates can influence water absorption in concrete?

The size and shape of the aggregates significantly influence water absorption in concrete due to their effects on surface area and packing efficiency. Smaller and more angular aggregates typically have a larger surface area compared to larger or more rounded aggregates, leading to greater water absorption. This is because the void spaces between smaller particles can hold more water, and the rough surfaces of angular aggregates can also create more surface area for water to cling to.

Additionally, the shape affects the overall packing of the aggregates in the concrete mix. Well-graded aggregates of various sizes can minimize voids, leading to lower water absorption compared to poorly graded or uniformly sized aggregates. Understanding this characteristic is crucial for achieving the desired concrete properties, as it directly impacts the water-cement ratio, workability, and ultimately the strength and durability of the concrete.

The other characteristics such as color, weight, and temperature have less direct influence on water absorption in concrete. While color might indicate moisture presence and affect thermal properties, it does not affect how water is absorbed. Weight can relate to specific gravity and density but does not directly impact the water absorption characteristics. Temperature can influence concrete hydration processes but does not inherently change the aggregate’s water absorption capabilities.