The Influence of Aluminum Hydroxide (Al(OH)₃) Additive on the Physical and Mechanical Properties of Alkali–Activated Slag

Alkali activation is a highly active and rapidly developing field of activity in the global research. Alkaliactivated cements have found a variety of applications: transportation, industrial, agricultural, residential, mining and so on. Alkali activated binders are made by mixing industrial aluminosilicate waste materials such as one of them is slag. This study aims to evaluate the influence of incorporating aluminum hydroxide on the physical and mechanical properties of alkali-activated slag. Mineralogy of composites were studied using X-ray diffraction analyze. The results showed that the molar ratio of raw materials strongly affects the kinetics of reaction and the structural evolution of the solid phases forming in alkali silicate activated binders. The role of Al(OH)3 in the mixtures in activated binders is closely related to the availability of Al in the system, because it controls the concentrations of secondary products such as zeolites. Based on the experimental results, it can be concluded that by reducing Al2O3 from 1.30 mol till 0.75 mol (in the mixtures of raw materials) the compressive strength of samples increases from 27 - 42 MPa till 39 - 54 MPa