ROCKBOND SURFACE RETARDER-PLUS (RB 7.17) is a concrete surface retarder and recommended to be used on concrete with strengths of 20 MPa and over, and on concrete under 20MPa in hot weather. When applied to the surface of freshly poured concrete it delays the normal hydration of cement for a depth of 3-6mm (and occasionally deeper), whilst the underlaying concrete hardens normally.
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