Early opening to traffic is an important requirement of rehabilitation in many urban areas with high levels of commuter traffic. Under such conditions concrete must often be placed at night or between morning and evening peak periods, and become strong enough to carry traffic within a few hours. The focus of laboratory and field studies on high early strength concrete has so far been mechanical properties, but not durability characteristics. The rigorous requirements for mixture design and strength development have always been stipulated for early-opening-to-traffic concrete, often with limited consideration to temperature control, crack control and curing. The long term durability of this type of concrete has not been established, and there are concerns that some concrete mixtures and construction practices compromise long term performance to achieve high early strength.

The goal of this research study is to evaluate the long-term durability of commonly used high early strength concrete, and to provide criteria for evaluating the suitability of new or modified combinations of materials for making durable high-strength concrete.