Lightweight concrete containing thermal power station and stone quarry waste

Abstract

Technology for the utilisation of highly porous bottom ash, formed as by-product of thermal power stations using pulverised coal combustion, is under development. The technology is based on the combined use of bottom ash as an aggregate and fly ash as an additive in the production of lightweight concrete. Such technology offers a solution to the persistent ecological and economical problems caused by coal ash. The following problems were addressed: (a) increasing the concrete strength with a low cement content and set resultant density; and (b) increasing the coal ash volume while maintaining rigid control of the concrete radioactivity – radionuclides ( 226 Ra, 232 Th, 40 K) present in coal ash. To solve both tasks, part of the bottom ash was replaced by a denser aggregate with a minimum radionuclide level; cheap unprocessed crushed sand was utilised. Favourable results suggest a widening of the utilisation of coal ash and quarry waste in lightweight concrete production.