Experimental investigation on the chemical and physical properties of activated glass powder pastes

This paper reports on the results of an investigation carried out to examine the ability of fine glass to be used in the concrete industry. The pozzolanicity of the glass powder (GP) hydration with and without calcium hydroxide (CH) (lime) is assessed using different methods. A comprehensive experimental programme is carried out to investigate the chemical and physical properties of the hydrated activated GP with CH, as a cement hydration product, on the microstructural level. The experimental work focuses on the degree of hydration, pH and the alkalinity nature of the pore solution to evaluate the performance of the GP when it reacts with the CH. A flame emission spectroscopy test was used to quantify the alkali release from the GP as well as determining the rate of alkali release with time. It was found that the GP releases a small fraction of sodium ions into the solution. Test results showed that the finely ground GPs exhibited very high pozzolanic activity. It was observed that the GP-lime pastes show high non-evaporable water content. Moreover, the best performance of the GP reactivity can be obtained in the range of 10.5 < pH < 11.5 depending on the CH/GP ratio. According to the scanning electron microscope analysis, the gel product of the GP hydration precipitates on the surface of the large particle of the GP, at which the very small micro particles and the outer layer of the large GP particles react with CH.