STORAGE OF AGGREGATES

One of the key factors when storing aggregates for concrete (or sand for mortars) is that they must be kept clean and dry. Water contained in aggregates and sands has implications for the water content of the finished mix, which in turn affects the workability and performance of the finished concrete or mortar. Contaminants such as soil, soluble salts from the ground, dirt, leaf matter, and so on, can cause staining or interfere with the bond between the cement paste and the aggregates in the mix.

Aggregates and sands delivered in 25-kg bags should be stored clear of the ground on a pallet. Inevitably, some bags will have been torn or punctured during original storage, transport or delivery, so it is good practice to cover the bags over with a tarpaulin or polythene. Deliveries made in 1-tonne ‘dumpy bags’ should, ideally, be kept off the ground on a pallet but if this is not possible they should be stored on a concrete or similar hard base. The most important factor is that they should never be in contact with soil. In all cases, the bags should be covered over with a tarpaulin or polythene to prevent rain ingress (or contamination by falling leaves during autumn).

Where loose deliveries are made by the lorryload, aggregates and sands should be stored on site on a hard, well-drained, sloping base. Ideally, the base should be made of concrete with the surface laid to a fall or slope to allow any water to drain out. On larger projects, purpose-built blockwork bays are constructed to provide separate storage for different aggregates. Again, the bays should be covered over with a tarpaulin or polythene.

STORAGE OF AGGREGATES

Fig. 6 A 25-kg bag of aggregate.

STORAGE OF AGGREGATES

Fig. 6 A 25-kg bag of aggregate.