Investigating the Influences of Ingredients, W/C Ratio and Dispersion Methods for CNT Modified Smart Concrete

Abstract

Carbon nanotubes (CNT) have excellent electromechanical properties and can be added into cement using appropriate dispersive means to produce CNT-modified cement-based smart materials (CNTCS). This study investigates how the ingredients, W/C ratio and dispersion methods influence the sensing ability of the smart concrete. Three different dispersion methods were investigated: direct mixing, surfactant surface treated with NaDDBS, and the Carboxymethyl cellulose (CMC) surface modification. CMC surface modification method showed consistency for modified cement paste and cement-sand composite material. For CMC surface treatment method, 0.6 w/c ratio was found to be optimal compared to 0.4 and 0.5. Coarse aggregate was added with cement and sand for 0.6 w/c ratio, and consistent piezo electric response was observed under dynamic loading for CMC surface treated smart concrete. However, significant reduction of sensitivity was observed between the CMC surface treated CNT modified smart concrete compared to smart cement-sand composite and the smart cement paste.