Concrete Mixing – Sub grade Preparation

Mastour ReadyMix is a Ready mix concrete and cement products company Jeddah, Khamis Mushyat, Dammam, Abaha Kingdom of Saudi Arabia

When stationary mixers are used, the first cubic meter of concrete should be mixed for 1 minute and each additional cubic meter should be mixed for 20 seconds. Mixing time starts when all cementing materials and aggregates are added to the mixer provided all of the water is added before 1/4 of the mixing time has elapsed. Concrete that is kept agitated does not get very stiff in the first 1/2 hour and usually can be placed and compacted up to 1 1/2 hours after mixing.

Moisten the sub grade when concrete is placed in warm or hot weather, and keep it unfrozen in cold weather. The sub grade should have even bearing, be drained, have no plant matter or frost, and should have the correct level or sloped contour. Undisturbed soil is generally better at supporting footings and slabs than compacted soil.