Pouring Concrete in HOT Weather
    Higher temperatures cause water to evaporate from the surface of concrete at a much faster rate causing cement hydration to occur more quickly, thereby causing the concrete to stiffen earlier and the chances of cracking. Cracking may result from rapid drops in the temperature of the concrete. This occurs when a slab or wall is poured on a very hot day which is immediately followed by a cool night. High temperature also accelerates cement hydration and contributes to the potential for cracking in massive structures. Higher relative humidity tends to reduce the effects of high temperature.