Thermal Conductivity of Cement Mortar Modified with Titanium Dioxide and Bentonite Nanoparticles – Comparative Analysis

The paper discusses the addition of bentonite and titanium dioxide nanoparticles in the cement mortar mix in terms of thermal conductivity. Calcined bentonite nanoparticles replaced cement particles in the mix by 1 wt%, 1.5 wt%, and 2 wt% per weight of cement. Titanium dioxide, being a non-reactive material, replaced the aggregates in the mix by 0.5 wt% and 0.75 wt% by weight of cement. A comparison between the individual impact of each type of nanoparticle, at 28 and 56 days of curing, on the thermal conductivity of the cement mortar was assessed. For evaluating the thermal performance, the density, surface moisture and thermal conductivity were recorded using laboratory equipment. The specific heat capacity value for each specimen was computed based on the volumetric heat capacity results given by the ISOMET 2114 device. The water content influence on the thermal performance was pointed out, as the 56 days samples registered a lower thermal conductivity and a higher specific heat capacity value. The higher hydrophilicity of bentonite was pointed out by the higher thermal conductivity at 28 days of curing. After water evaporation, at 56 days, the smallest thermal conductivity value was obtained for 0.5 wt% TiO2 – modified cement mortar specimen. The highest specific heat capacity at 56 days of curing was registered for 0.75 wt% TiO2 – modified samples.