Evaluation of the effect of nanosilica and recycled fine aggregate in Portland cement rendering mortars

ABSTRACT This paper evaluated the incorporation of nanosilica (NS) in rendering mortars produced with recycled fine aggregate (RFA). Initially, a study was carried out on cementitious pastes, replacing Portland cement NS at levels 0%, 0.4%, 0.6%, 0.8%, and 1.0%. The samples were submitted to scattering, rheology, calorimetry, x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), compressive strength analysis 28 days. results demonstrated that pastes 0.4% 0.6% presented an increase 55% 58%, respectively, due greater formation calcium silicate hydrate (C-S-H), when compared reference paste. From that, RFA produced, 0% NS, NS. At days, mechanical performance, microstructure, durability by means flexural compression, scanning electron microscopy (SEM), dynamic elasticity module, water absorption capillarity. results, it concluded resulted optimal content, increasing values reducing sorptivity, relation other mixtures. SEM images suggest reacted portlandite formed hydration, improving microstructural development samples.