In recent years, lime mortars mixed with artificial or natural pozzolans are commonly\nused in restoration applications. The aim of this work is the assessment of carbonation, pozzolanic\nreaction, setting time, and mechanical properties of metakaolinâ??lime mortars mixed with crystalline\nnano-titania (nT) as additive. The studied mortars consist of hydrated lime and metakaolin in\n60/40 ratio (wt%) and fine aggregates of either carbonate or silicate sand. The concentration of the\nnano-titania is equal to 6 (wt%) of the binder. For comparison purposes, three types of mortars\nand pastes are designed: Without the addition of nano-titania, with nT activated or not under UV\nirradiation. The evaluation of the carbonation and pozzolanic reaction over a 1.5-year curing period\nis carried out through thermal analysis (DTA/TG), infrared spectroscopy (FTIR) and X-ray diffraction\nanalysis (XRD). The uniaxial compression and the three-point bending tests at 28 days, 3 months, and\n6 months were carried out to evaluate mechanical properties. The addition of activated nano-titania,\ndue to an increased photocatalytic activity, accelerated the setting of the mortars, improving at the\nsame time the mechanical properties. The plastic behavior of the limeâ??metakaolin mortars with\nactivated nT was attributed to the evolution of carbonation and pozzolanic reaction.
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