Aggregate Cement Ratio

The aggregate-cement ratio is the weight of the total aggregate to that of cement in a concrete mix.

A higher aggregate-cement ratio results in a concrete mixture with less cement, leading to a reduction in the workability.

Conversely, a concrete mixture with a lower aggregate-cement ratio, known as a rich mix, contains more cement paste, yielding improved workability because cement paste facilitates the smooth movement of aggregate particles.

A higher aggregate-cement ratio typically exhibits increased strength when the water-cement ratio is constant.

Reducing the aggregate-cement ratio with a constant water-cement ratio increases water content, thus enhancing consistency. If the water content is fixed but the aggregate-cement ratio is lowered, the water-cement ratio drops without affecting the consistency.

With a smaller percentage of the concrete volume being taken up by the cement paste, as seen in leaner mixes, the total porosity of the concrete diminishes, resulting in enhanced strength, which excludes the voids within the aggregates themselves.

The voids within the normal aggregates are usually insignificant and do not substantially impact the strength of the concrete.