Design-driven approach for engineered geopolymer composite with recorded low fiber content
Fei Wang, Jiabao Zhai, Yao Ding, Tomoya Nishiwaki, Jiangtao Yu, Victor C. Li, Kequan Yu
Abstract
How to design an engineered cementitious composite (ECC) achieving both economic viability and ultra-sustainability has been the longstanding goal of ECC community. This study presents a design-driven approach to tackle this challenge through yielding a low matrix fracture toughness and a sufficiently strong interfacial bonding between fiber and matrix concurrently. As a result, only 0.2 % fiber content was sufficient for achieving robust strain-hardening in Engineered Geopolymer Composite (EGC), which, to the authors’ knowledge, is the lowest recorded thus far. The tensile strain-to-fiber content ratio reached 25, a remarkable 233 % higher than the existing strain-hardening composites. Besides, the compressive strength was around 40 MPa, marking the highest specific strength among the ECCs with a density below 1450 kg/m 3 . Leveraging the high porosity of 38 % and the presence of shrinkage micro-cracks in the matrix, a low fracture toughness, combined with a robust friction between fiber and matrix, facilitated the noticeable strain-hardening. The reaction product was identified as a dense alkaline aluminosilicate hydrate (N-A-S-H) gel, benefiting the interfacial bonding and compressive strength. The embodied energy and carbon of the EGC diminished by 27 % and 63 % compared to ordinary concrete, respectively, and the corresponding cost was 79 % lower than the classic M45-ECC, contributing significantly to ultra-sustainability.