Study of the action of nano-alumina particles in hydrated lime pastes

Abstract

The present study aims to describe the effect of the addition of nano-alumina (NA) in the properties of hydrated lime pastes. Different proportions of NA (0%, 3.0%, 6.0% and 12.0%w/w) were added in hydrated lime, the specimens were cured for a 90-day-period and the mechanical and microstructural properties were studied. The X-Ray diffraction (XRD) patterns revealed the formation of Ca–Al–CO3-LDH compounds at early age lime pastes. The accelerated carbonation of NA-modified systems, the interlayer water and the hydroxyl groups of Ca–Al–CO3-LDH compounds were recorded using thermogravimetric analysis (TGA). Attenuated total reflection (ATR) assignments confirmed the findings mentioned above by identifying the formed carbonate groups. The calcium aluminate carbonate hydrate compounds (Ca4Al2O6(CO3).11H2O) that were formed were found to be unstable in time. As a result, their decomposition led to the acceleration of carbonation and compressive strength enhancement. NA improved the inherent weakness of hydrated lime by providing early age strengthening.