8.2 : وقت الخلط

Concrete mixers are initially charged with 10 percent of the total water, followed by consistent additions of solid materials and 80 percent of the total water.

The duration of mixing begins as soon as all components are in the mixer. The remaining 10 percent of water is incorporated within the initial quarter of the total mixing duration.

Mixing for less than 1 to 1.5 minutes can lead to a non-uniform concrete mix with lower strength.

The optimal mixing time to produce uniform concrete depends on mixer capacity; a minimum of one minute of mixing is required for a mixer with a capacity of up to one cubic yard, which increases by fifteen seconds for each additional cubic yard.

Furthermore, mixer type, rotation speed, and blending quality during the charging of ingredients are key to determining the optimum mixing time.

Prolonged mixing can lead to water evaporation from the mix, grinding of soft aggregates, decreased workability of the mix, an increase in the mix temperature due to friction effects, and a decrease in air content for air-entrained concrete.