Manufacturing and properties of composite material from demolition debris, plaster waste, and lime production waste to decrease ecological problems of cities

The main goals of this study were the development of new composites of construction materials from three types of construction industry wastes: construction and demolition debris, plaster waste, and lime production waste; determination of the physical-chemical processes of new composites structure formation. The study was using the methods of X-ray powder diffraction, scanning electron microscopy, energy dispersive spectroscopy, and laser micro-mass analyses. The strength of the test samples on the 180th day reached 16.7 MPa, the coefficient of linear expansion during hydration and hardening of the test samples till 1.81%, the water absorption 14.9%, and the apparent density till 1.95 g/cm³. The processes of structure formation showed hardening of the materials due to alkaline dissolving of the surfaces of solid particles, followed by chemical interaction of these alkaline solutions, with the synthesis of predominantly amorphous new sol-gel formations of the CSH group and of carbonates; over time, these new gel formations are transformed into a stony state.