Surecrete SureCast™ SC-35103001-10 60 lb Dark Walnut Dry Powder Concrete Color Hardener. SureCrete’s SureCast™ concrete colored hardener is premixed, dry-shake, colored powder concrete hardener. It is used for coloring and hardening freshly placed concrete flat work to produce an aesthetically pleasing pavement with a surface that is substantially harder and more wear-resistant than regular concrete. This coloring method can be utilized for concrete applications (salt finishes, broom finishes, rotary finishes, etc.), as well as vertical surfaces and other types of architectural concrete.