Characterization of ultra-high-performance cementitious composite incorporating carbon nanotubes

Ultra-High-Performance Concrete (UHPC) is a type of concrete with unique mechanical and durability characteristics, developed to meet the global demand for extreme construction. Typically, UHPC is produced using customized mix design and subjected to special curing condition. Concrete is a brittle material in nature, where UHPC has its drawbacks in terms of lower tensile strength ratio and brittleness. Carbon nanotube (CNT) is a potential candidate to act as nano-reinforcement in UHPC matrix, to create a denser and a more ductile Ultra-High-Performance Cementitious Composite (UHPCC) system. The consistent dispersion of CNT in the cementititious matrix is a challenge due to their high aspect ratio and its agglomerating behavior. This paper presents on the fundamental UHPCC mix design which optimizes on its packing density with fewer constituent materials. The mechanical strength and microstructure characteristics of three types of UHPCC developed with CNT, which were produced with different dispersion methods are reported. It was found that stable CNT dispersion enhanced the microstructure characteristics of the UHPCC matrix, and achieved higher flexural strength (more than 60% higher) and marginally higher compressive strength, compared to control specimens without CNT.