Mechanical and smart properties of cement nanocomposites containing nanomaterials: A brief review

We report a brief review on the recent developments on smart cement nanocomposites. Cement nanocomposites containing functional nanomaterials are important class of materials for the development of sustainable civil infrastructures. Smart properties can be achieved by adding various nanomaterials, such as, titanium oxide (TiO2), iron oxide (Fe2O3), graphene, graphene oxide (GO), carbon nanotubes (CNTs), carbon nanofibres (CNFs), and polymers at low weight percent (wt%) to cement. However, optimization and understanding of underlying physical and chemical mechanisms are necessary for further developments. Although, there exist huge research articles, and some reviews dealing with specific aspect over the last 10-15 years, a systematic review is necessary, encompassing both the aspects of mechanical properties as well as smart properties. In the present review, we focus on the effect of addition of functional nanomaterials to achieve smart properties maintaining basic mechanical strength at the desired level. Our review shows that addition of TiO2, SiO2, Fe2O3, CNTs, or GO in the range of <5 wt% improves mechanical strength by similar to 30-50% or more due to improvement in the filling of pores, bridging of gaps, and prevention of cracks. Addition of functional nanomaterials show higher photocatalytic dye degradation (similar to 90% dye pollutant is degraded within first 1 h), higher inhibition zone of microbial growth (due to the addition of 1 wt% (or less) TiO2, silver, copper oxide, or zinc oxide nanoparticles). Furthermore, addition of functional nanomaterials also show improvement in the impermeability, shrinkage, hydrophobicity, thermal/electrical conductivity, and piezo electricity to a significant level.