Multiscale Investigation on the Performance of Engineered Cementitious Composites Incorporating PE Fiber and Limstone Calcined Clay Cement (LC(3))

Limestone calcined clay cement (LC(3)) is successfully used to fabricate engineered cementitious composites (ECC) exhibiting tensile strength σ(tu) of 9.55 ± 0.59 MPa or tensile strain capacity ε(tu) of 8.53 ± 0.30%. The high tensile strength of the composites is closely related to the improvement of fiber/matrix interfacial bond strength, and the high ductility is attributed to the enhancement of fiber dispersion homogeneity. For the case of ECC incorporating 50% LC(3), the reduction of initial cracking stress σ(tc) that favors the growth of the crack in a controlled manner also contributes to the improvement of strain hardening behavior. The composition analysis indicates that carboaluminates and additional hydration products including C-(A)-S-H and ettringite are generated, which contributes to the densification of the microstructure of the ECC matrix. The pore structure is thus remarkably refined. Besides, when ordinary Portland cement (OPC) is partly replaced by LC(3), the consumed energy and equivalent CO(2) emission decrease, especially the equivalent CO(2) emission with the reduction ratio attaining 40.31%. It is found that ECC using 35% LC(3) exhibits the highest mechanical resistance and ECC incorporating 50% LC(3) shows the highest ductility from the environmental point of view.