Critical overview of two-stage concrete: Properties and applications

• Two-stage concrete (TSC) technology and history are presented.
• The materials specifications for TSC are outlined.
• The engineering properties of TSC and its long-term performance are compiled.
• Future research on TSC and need for further development are discussed.

Two-stage concrete (TSC), also known as preplaced aggregate concrete, is a special type of concrete that is produced using a unique procedure which differs from that of conventional concrete. In TSC, coarse aggregate particles are first placed in the formwork and voids between them are subsequently injected with a special cementitious mixture. TSC has been successfully used in many applications, such as underwater construction, casting concrete sections congested with reinforcement and concrete repair. This paper provides a critical overview of TSC, including its development history, material specifications, engineering properties and long term-performance. This critical overview of the TSC state-of-the-art should enhance the understanding of its behaviour, thus paving the way for wider implementation of its use in today’s concrete industry.