Physical-mechanical properties of mortars with addition of TiO2 nanoparticles

•Lime-, cement- and lime & cement-based mortars containing TiO2 have been investigated.•Physical-mechanical properties induced by the introduction of TiO2 were studied.•Higher TiO2 content leads higher open porosity and water accessible coefficients with exceptions.•Global colour change showed a direct relation with the TiO2 content.•Mechanical properties were inversely related with the hygric properties.

Lime-, cement- and lime & cement-based mortars, containing different proportions of nanocrystalline TiO2 (1, 2.5 and 5 wt%) and fine aggregates of silicate nature have been investigated with the aim to improve the knowledge in terms of their chemical, physical and mechanical properties. The influence on the physical-mechanical properties induced by the addition of TiO2 were evaluated through measurement of chromatic parameters, open porosity, water absorption coefficient at atmospheric pressure, P-wave velocity, material loss by peeling test and microdrilling resistance and compared to the reference mortars ones, i.e., without the TiO2 nanoparticles addition. Moreover, stereo and electronic microscopy were used to study the morphology, the mineralogical and chemical composition of each mortar formulation. Fourier transform infrared spectroscopy was also applied to gather qualitative information on the chemistry of some of the characteristic components of the mortar.The results suggest that the physical-mechanical properties of the studied mortars were influenced by the TiO2 nanoparticles addition. Furthermore the influence of the TiO2 on the properties of the studied mortars is also dependent on the nature of the binder used. Nevertheless, in general terms, the global colour change showed a direct relationship with the TiO2 content. Regarding the hygric properties, mortars with higher addition of TiO2 content showed higher open porosity and water absorption coefficients, but an exception for the cement-based mortar with 2.5 wt% was detected. The values obtained in the mechanical properties evaluated were inversely related with the hygric parameters.

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