Development of a self-consolidating engineered cementitious composite employing electrosteric dispersion/stabilization

A self-consolidating engineered cementitious composite (ECC) reinforced with hydrophobic polyethylene fibers has been developed by combining micromechanics based design and rheological design, in a compatible manner. The previously developed micromechanics based design selects material ingredients for tensile ductility in the hardened state. The rheological design, which is the focus in this paper, modifies the material ingredients for self-consolidation behavior in the fresh state. For this purpose, the rheological design adopts a complementary electrosteric dispersion and stabilization technique to obtain cement pastes with desirable flow properties at constant particle concentrations dictated by the micromechanics based design. Such stabilization is realized by optimizing the dosages of strong polyelectrolyte and non-ionic polymer and by controlling the mixing procedure of the polymers. The fresh cement paste designed thereby leads to fresh mortar mix with desirable deformability, cohesiveness, and high consistency, and thus satisfies the self-consolidating performance of fresh ECC mix. In addition, ductile strain-hardening performance of the self-consolidating ECC is confirmed through uniaxial tensile test. This ductile composite with excellent fluidity can be broadly utilized for a variety of applications, e.g. in repair of deteriorated infrastructures requiring horizontal formworks, or in seismic-resistant structures with dense reinforcements and requiring high ductility.