Engineered geopolymer composite (EGC) with ultra-low fiber content of 0.2%

Engineered cementitious composite (ECC) features with excellent tensile performance. However, two major drawbacks, including the high environmental impacts associated with high content of cement and the high cost caused by high fiber content, impede the wide application of ECC. This study designs and successfully develops a high ductile cement-free engineered geopolymer composite (EGC) with ultra-low content of fibers (0.2% by volume, EGC-0.2%). EGC-0.2% exhibits a tensile strain capacity above 4% and a controllable crack width around 200 µm. The compressive strength reaches 39 MPa and the density is below 1200 kg/m3, showing an excellent specific strength (the ratio of the compressive strength-to-density) of 37 kPa/(kg/m3). The matrix fracture toughness of the developed EGC is low to facilitate the high ductility of the EGC-0.2% by such low fiber content. In addition, EGC-0.2% presents extremely low environmental impacts and cost. The embodied energy and embodied carbon decrease by 23% and 67% than conventional concrete, respectively, and the cost is only 21% of the classic M45-ECC with similar mechanical performance. The current findings provide valuable references for the future advancement of ECC towards high sustainability and cost effectiveness.