Using coal-fired thermal power plant ash to replace part of cement in the manufacturing of concrete insert plates to reduce greenhouse gas emissions
Abstract
Vietnam currently has 26 coal-fired thermal power plants in operation, discharging a total of about 16 million tons of fly ash (FA) and coal bottom ash (CBA). FA and CBA increase storage costs and negatively impact the environment. Currently, steel arc supports frames with insert concrete plates are the most common type of support structure in underground mining (about 70 - 80%) in the Quang Ninh coal region, Vietnam. In addition, the number of monolithic concrete casing tunnels has increased rapidly due to increased mining depth and the opening of new mining areas (mines: Ha Lam, Mao Khe, Khe Cham II, Nui Beo, Nam Mau, ...) passing through areas with complex geological conditions such as breaking, faulting, flaring, tunnels with large deformations on the edge, tunnels dug through water-bearing areas... At the main tunnels, vertical shafts, intersections, platforms... of underground mines, monolithic or prefabricated concrete casing structures need to be used with large thickness. For large-scale projects such as vertical shafts with great depths of up to thousands of meters when mining deep, the volume of concrete materials used as casings and concrete filling behind the casing is very large, up to millions of m3, increasing material costs and transportation costs of materials to the pouring location. With prefabricated concrete casings, insert concrete plates due to their large size and weight make them difficult to transport, carry and support in the narrow conditions of the great depths of Vietnamese underground mines. Therefore, it is necessary to study the maximum use of fly ash and coal bottom fly from coal thermal power plants to replace a part of the cement in the manufacture of concrete casings, insert concrete plates, backfill materials... of tunnels to reduce greenhouse gas emissions and reduce the amount of cement used. The study proposes the optimal ratio of FA and CBA of coal-fired thermal power plants used in concrete mixtures to manufacture insert concrete plates for basic tunnels through experimental methods at the Construction Laboratory, University of Mining and Geology (HUMG)
