Incorporating nanomaterials into high strength ECC: Boosting self-healing and mechanical properties for marine infrastructure

Cracking is an inherent phenomenon in concrete, and engineered cementitious composite (ECC) is not exempt from this limitation, even though it can effectively restrain the crack from opening. This study aims to enhance the self-healing capacity of ECC mixtures through the incorporation of nanomaterials. The effects of nano-magnesium carbonate (NM), calcium carbonate (NC), and aluminum (NA) on ECC properties were characterized through tensile test, water sorptivity test, and self-healing observations. Experimental results showed that the addition of nanomaterials improved overall tensile performance. Specifically, tensile strain capacity, first cracking strength, and tensile strength increased from 4.35%, 4.02 MPa, and 6.46 MPa for the reference mixture (Ref.-ECC) to 7.85%, 4.56 MPa, and 8.52 MPa, respectively. Additionally, the water sorptivity of ECC mixtures with nanomaterials, whether cracked or not, was lower than that of Ref.-ECC, which contributes to improved durability. Ref.-ECC almost lost all of its self-healing ability for wide cracks (>80 μm), while the nanomaterial-modified ECC still exhibited commendable self-healing behavior. It was found that the self-healing efficiency of the nanomaterial-modified ECC under seawater exposure was higher than that under tap water exposure. These findings suggest that nano-material modified ECC can be a viable material for marine infrastructures.