Rheological Control in Production of Engineered Cementitious Composites

Abstract

A study of fresh property rheological control during engineered cementitious composite (ECC) processing for the purpose of more effective realization of mechanical properties using micromechanical design theory optimization is reported on in this paper. To determine their effects on fresh and hardened ECC properties, there was investigation of four factors (amount of viscosity-modifying admixture, amount of high-range water reducer [HRWR], water-binder ratio [w/b], and Class C fly ash [FA] to Class F FA ratio). That the w/b, among investigated factors, most strongly affects ECC mortar (without fiber), which in turn significantly impacts ECC composite tensile strain capacity and ultimate tensile strength, is indicated in test results. The mini-slump flow test and marsh cone flow test were shown to be simple and practical methods for ECCC mortar rheological property characterization. Self-consolidating ECC with optimum rheological properties promoting uniform fiber distribution through the matrix can be produced easily, and micromechanically based optimized ECC mixture design optimized tensile properties can be realized through compliance recommendation for rheological control for ECC production as summarized in this paper.