Concrete carbonation problem

The surface pale white, a layer of flour appear with the foot rub.

Reason: The hot summer temperatures, after pouring the concrete cover caused by excessive water loss is not timely,

but not timely water conservation or conservation but more than the strength of concrete the best growth period (already "thirst"),

resulting in the conservation of failure.

Full summer water conservation initial setting of concrete (about two hours), the cover must be timely, the final setting (about five hours) after: prevention.