What impact do larger aggregate sizes typically have on concrete?

Larger aggregate sizes can significantly influence the properties of concrete, particularly in terms of its strength. When aggregates are larger, they typically occupy more space within the concrete mix, which can lead to a reduced surface area for cement paste to bond with. This can result in a weaker concrete mix if not properly managed, as there may not be sufficient paste to fill the voids between the larger aggregates, leading to potential weaknesses in the overall structure.

While larger aggregates can sometimes improve certain aspects, such as reducing shrinkage and potentially decreasing the amount of cement needed, they do not inherently improve the strength of the concrete and often, if not balanced correctly with the right mix design, can lead to weaker concrete due to reduced bonding surface areas. This understanding is crucial for achieving the desired strength and performance in concrete applications.