Effect of alkali activator concentration on waste brick powder‑based ecofriendly mortar cured at ambient temperature

摘要

The main goal of this research was to investigate the effect of alkali activator concentrations and fine aggregate types on theperformance of waste brick powder (WBP)-based alkali-activated mortar. Ground granulated blast furnace slag was used tomodify the properties of WBP. Na_2SiO_3 and NaOH were used as the alkali activator solutions, with Na_2Ocontent varyingbetween 2 and 10% and the SiO_2/Na_2O ratio varying between 0.25 and 2. Waste ceramic sand (WCS) and recycled concretefine aggregate (RFA) were used as the alternative fine aggregate materials to replace natural fine aggregate (NFA). The mortarmixtures were successfully developed at significantly lower alkali activators concentrations (starting from 4% Na_2Oand SiO_2/Na_2O ratio of 0.5) than previously reported in the literature. The compressive strengths of the mortar were measuredbetween 8 and 46 Mpa. The partial replacement of NFA by WCS enhanced the compressive strength of mortar. Scanningelectron microscope, energy dispersive X-ray spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopyanalysis were used to study the microstructural properties of mortar. Higher compressive strength and an increasingly compactmicrostructure were observed as Na_2O content increases from 4 to 10% and as the SiO_2/Na_2O ratio rise from 0.5 to 1.5.