Testing nano-silica and nano-alumina additions for enhancing the durability of cement and lime pastes

The present study aims to record the influence of nano-particles on the durability of cement and lime pastes exposed to salt cycles. As salts are a significant pathology factor for materials exposed to marine or other corrosive environments, the influence of nano-technology towards the protection of materials is of great importance. The incorporation of nano-silica (NS) and nano-alumina (NA) in cement and lime pastes influenced the physic-mechanical properties and the behavior of the pastes through the salt cycles. NA provoked compressive strength increment, open porosity reduction and water absorption in lime pastes at 90 and 180 days. Additionally, it allowed the enhancement of compressive strength after sodium sulfate cycles. XRD (X-Ray Diffraction) analysis and ATR (Attenuated Total Reflectance) spectroscopy contributed to the explanation of the high compressive strength recorded after the sodium sulfate cycles of NA-modified lime pastes. In case of cement pastes, NS favoured the compressive strength after the sea water and sodium sulfate cycles. Moreover, NA aided the enhancement of the properties of the pastes in the latter conditions. (C) 2019 Elsevier Ltd. All rights reserved.