Environmentally clean composites with hazardous aluminum anodizing sludge, concrete waste, and lime production waste

Abstract

The main purpose of this research was to study the influence of highly alkaline additives of aluminum anodizing waste (AAW) on the mechanical properties and structure formation processes of the cement-less construction material like non-burnt bricks and blocks based on concrete and lime production waste. The test specimens from 12 compositions of AAW, concrete waste (CW), and lime production waste (LPW) were homogenized, moistened, compacted at 10 MPa and strengthened outdoors.The axial strength values of the developed materials on the 3rd day of curing reached till 5.9 MPa; after the 7th day - till 6.8 MPa; after the 28th day - 7.9 MPa and after the365th day 13.4 MPa. The water absorption values after 28 days of curing went from 12.33 to 13.86% and at 90 days - between 11.18 and 12.74%. The expansion coefficient of the test specimens after 28 days of curing varied between 1.1 and 2.6% and after 365 days between 0.9% and 2.2%.The study was conducted on physical and chemical interaction processes of components of structure formation in the moist alkaline environment performed by complementary methods of X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), laser micro-mass analysis (LAMMA), and atomic absorption spectroscopy (AAS). The study showed that the new mainly amorphous formations were responsible for the physical strengthening during the first year of hydration.