Mechanical performance of self-consolidating concrete at early age

The growing use of self-consolidating concrete (SCC) in North America has lead to many practical questions about the mechanical performance of this material. SCC is designed to have fresh concrete properties that allow the material to consolidate under its own weight and completely fill formwork without the need for external vibration. SCC is highly fluid, but must be sufficiently cohesive to prevent segregation. Much attention is paid to achieving the required flowability and stability, while more research is needed on the resulting impact on hardened properties. Mechanical properties can be influenced by SCC strategies such as using higher paste content with or without mineral additives, lower w/c ratio, and uniformly graded aggregate with a greater portion of fine particles. The early age mechanical performance was investigated with experiments that measure shrinkage, creep under tensile stress, and strength development. Results indicate that SCC mechanical properties depend on strategy and mixture proportions. As with ordinary concrete, self consolidating concretes can be produced with a wide range of volume stability and mechanical properties. Implications for early age cracking and long-term durability of different SCC strategies are discussed.