Mechanism study of crack propagation in river sand Engineered Cementitious Composites (ECC)

While incorporation of river sands improves the volume stability and lowers the cost of ECC, distinct multiple cracking and tensile strain-hardening behavior of the resulting river sand ECC (RS-ECC) with different strength grade were observed. This paper investigates the effects of river sand inclusion on crack propagation in RS-ECC. It concludes that crack deflection at RS/matrix interface prevails in the normal strength RS-ECC while crack penetration through RS dominates in the high strength RS-ECC. As a result, crack path in the normal strength RS-ECC is more tortuous which increases matrix fracture toughness and lead to less saturated multiple cracking and reduced tensile strain capacity. Crack branching can occur when the crack propagates through the RS in the high strength mix, resulting in more saturated multiple cracking in the high strength RS-ECC with improved tensile strain capacity.