The deterioration and environmental impact of binary cements containing thermally activated coal mining waste due to calcium leaching
StatisticsView Usage Statistics
Full recordShow full item record
Thermally activated coal mining waste
Calcium-leaching processes can potentially degrade the structure of a concrete matrix. This problem is studied here through the progressive dissolution of Ca2+ in both ordinary Portland cement pastes (C-0) and binary cement blends (C-20) containing 20% thermally Activated Coal Mining Waste (ACMW).1 A series of accelerated tests are conducted that involve the immersion of these cement pastes in a 6 M ammonium nitrate solution at a temperature of 20 C for 7 and for 21 days. A rise in paste porosity was observed, due to increased capillary pore sizes of between 5 and 0.1 μm. In the case of the 20% ACMW pastes (C-20), calcium leaching decreased, probably as a consequence of the pozzolanic effect of the ACMW, while potassium and magnesium leaching increased, due to the presence of the phyllosilicates in the ACMW. The paste compounds most affected by leaching were Ca(OH)2, C6AS3H32, and C4AC¯H12. In general terms, it can be concluded that the incorporation of ACMW into binary cements slightly ...