CHRYSO®Tard CHR slows down the hydration of cement by momentarily blocking the surface of the cement particles. At the end of setting, the concrete hardens rapidly and high compressive strength is obtained after 28 days. CHRYSO®Tard CHR has no surface tension effects. Its use in concrete modifies in no way the onsistency of concrete. CHRYSO®Tard CHR can be used simultaneously with high range water reducing superplasticizers.