Ultra-low carbon lightweight engineered cementitious composite: Design and material characterization

Lightweight engineered cementitious composites (LWECC) are prized for their exceptional tensile performance, durability, and low self-weight. However, the elevated cement usage in ECC results in a substantial carbon footprint, thus placing significant ecological pressures. This study employed calcium sulfoaluminate-activated supersulfated cement (CSA-SSC) to develop the ultra-low carbon LWECC. The influence of silica fume, lightweight filler, PE fiber contents and water-to-binder ratio on the mechanical characteristics of ULL-ECC were investigated, in terms of density, tensile and compressive properties. The fracture toughness test, single-crack tensile test, mercury intrusion porosimeter (MIP), scanning electronic microscope (SEM) and X-ray diffraction (XRD) analysis were conducted to establish a connection between macro behavior and micro-scale performance. The results reveal ULL-ECC's remarkable tensile behavior, demonstrating a tensile strength of 7.1 MPa and an impressive strain capacity of 12.6%, with compressive strengths ranging from 50.3 MPa to 65.1 MPa. The carbon footprint of ULL-ECC accounts to only 35% of conventional concrete and 22% of traditional ECC. Through the synergistic utilization of eco-friendly FAC, CSA-SSC, and high-strength PE fiber, ULL-ECC not only showcases exceptional mechanical properties but also embodies a substantial improvement in sustainability, coupled with a reduction in self-weight.