Use of silica particles to improve dispersion of -COOH CNTs/carbon fibers to produce HyFRCC

Abstract

The development of hybrid fiber reinforced cement composite that has high strength, scope to be used as cement-based sensors has been investigated in this study by using a combination of carbon fibers and carbon nanotubes (CNT) at low volume fraction. The dispersion of CNTs was enhanced by using polycarboxylate based superplasticizer that resulted in a homogeneous aqueous stable solution, and profoundly improved dispersion when integrated with the cementitious matrix. Different siliceous additives were also incorporated into the mixes to improve the dispersion of CNTs in the matrix, where micro-silica outperformed as compared to nano-silica, confirmed morphologically. On the other hand, nano-silica enhanced dispersion of milled carbon fibers in the aqueous state. The sensing behavior was determined by the measurement of bulk resistance of mixes and the samples were subjected to compressive loading to study the strength improvement with the incorporation of fibers. The experimental results reveal that hybrid combination of chopped carbon fibers, micro silica, and low volume fraction of CNTs in a cementitious matrix results in a stronger and durable concrete that holds the potential for sensing applications. Thus, laying a strong foundation for the future of low cost smart cement based materials.