Towards a comprehensive framework for foam concrete mix design

Abstract

Foam concrete is a low-density, highly workable cementitious material, created by blending a fine-aggregate paste with a foaming agent. Properties of foam concrete suggest potential for commercial exploitation of the material in a wide variety of applications and markets. However, reliably designing a foam concrete mix to a particular specification has proved a difficult challenge and a barrier to more widespread usage. This thesis builds a comprehensive framework for foam concrete mix design. A strategic set of mixes, across a broad range of densities, cementitious densities, and cementitious blends, is evaluated for an extensive array of properties: compressive strength, density, slump flow, segregation, modulus of elasticity, Poisson’s ratio, crushing behaviour, creep, drying shrinkage, capillary water uptake, moisture storage, moisture movement, thermal conductivity, freeze-thaw resistance, and air-void distribution. Critical and previously neglected engineering properties are quantified and characterized. A proposed model assimilates interrelated trends, to explain observed behaviour of foam concrete in plastic, curing, and hardened phases at a micromechanical scale. Knowledge is summarized in a series of mix design guides, to assist in developing appropriate solutions for given applications, with less reliance on trial-and-error and speculation. Finally, this study lays a foundation for a systematic and methodologically consistent approach to future foam concrete research.