Aggregates Moisture

Aggregates are usually stocked outside, hence temperature, rain, air relative humidity, sun greatly influence their moisture content, which is an important parameter in concrete technology. Aggregate can be in different conditions, as shown in Figure 10 When aggregate are dry or humid, they subtract water to the fresh concrete mixture, while when they are wet they supply an additional amount of water to the mixture.

Only in saturated surface dry conditions the aggregate do not alter the concrete proportions and in fact, in the concrete formulation, aggregate are always considered in saturated surface dry condition. Of course, aggregate are usually not in this condition, thus the water introduced in the mixture must be corrected accordingly (increased when aggregate is dry, decreased when aggregate is wet).

Even if the moisture percentage in aggregate is not very high (1-10% percent in most of cases), the total amount of water added to or subtracted from the mixture is very significant, due to the large quantity of aggregate per cubic meter.