Alkali-activated cement manufactured by the alkaline activation of demolition and construction waste using brick and concrete wastes

Abstract

This study examines the mechanical and materials science properties of a novel Alkali-activated cement (AAC) cured at room temperature and using construction and demolition waste (CDW), which was obtained from brick and concrete waste from a landfill in Medellín, Colombia. The cement was activated with an aqueous solution of sodium hydroxide and sodium silicate. Different mixtures were tested to determine the optimum amount of CDW and the proportion of alkaline activator. The formulations were characterized by compressive and flexural strength tests, X-ray diffraction, scanning electron microscopy, and water absorption tests. Results indicate that the mechanical properties of the developed cement are strongly influenced by both the type of activated residue and the activator ratio. The AAC with the best mechanical properties is the one based on brick waste, which has a mean compressive strength of 33 MPa.

Keywords

• Alkali-activated cement
• Geopolymers
• Construction and demolition waste
• Alkaline activation
• Cement
• AAC