Enhancement of structural response in members built with engineered cementitious composites (ECC)

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Engineered Cementitious Composite (ECC) mortar is a fibre-reinforced, cement-based material designed to exhibit high ductility in tension. Polyvinyl alcohol fibres (PVA) embedded in the mix allows ECC to reach ultimate tensile strains from 3% to 5% with no visible damage. Instead of developing a single, wide crack in tension as plain concrete does when it fractures, ECC develops multiple micro-cracks which translate into a pseudo-ductile behaviour after first crack. This allows for greater deformations in structural members made with ECC, since the fibres in tension can sustain deformations up to 500 times more than conventional concrete. ECC has been used at the coupling beams and shear walls of high-rise buildings in Japan, bridge superstructures, and to mitigate cracks in dams. In North America, ECC has been used in a few building and bridge structures. In Canada, the use of this remarkable material for structural purposes in Canada is very limited. It is recognized that a more widespread use of ECC requires a thorough understanding of the mechanical properties of this innovative material. Shear behaviour is a particularly important aspect to study since overestimating the shear strength of structural members may lead to brittle and catastrophic failures. This research intends to assess the feasibility to fabricate ECC with raw materials local to the province of Alberta, characterize its material properties, and investigate the shear behaviour of ECC. The goal of the study is to show that ECC is a viable alternative to conventional concrete, with superior resilience, shear strength and ductility in tension.