Strain hardening magnesium-silicate-hydrate composites with extremely low fiber dosage of 0.5% by volume

Abstract

Formulation of strain hardening cementitious composites typically engage 2% or more fiber by volume, resulting in higher cost and difficult processing. This study presents the development of strain hardening magnesium-silicate-hydrate composite with an extremely low fiber volume fraction of 0.5% via micromechanics-guided design approach. The developed composite demonstrated a tensile strain capacity of 7.2% with a tensile strength of 2.24 MPa, and a compressive strength of 86.1 MPa. The fiber/matrix interfacial bond was characterized using single fiber pullout test. The microstructural characterization of fiber surface and fiber tunnel in the matrix was carried out to understand the fiber/matrix interface properties. The micromechanics-based assessment of critical fiber volume fraction required to achieve strain hardening was also conducted. The material sustainability of the developed composite was evaluated and compared with existing Portland cement-based strain hardening cementitious composites, and strategies to further reduce embodied carbon and primary energy were proposed.