Surface scaling resistance of concrete with fly ash from co-combustion of coal and biomass

Abstract

The co-combustion of coal and biomass is connected with enforcing EU regulations concerning the application of renewable sources of energy. The more widely and efficiently that fuel is utilized the better this fact affects the ecology as well as the economy. The combustion of biomass and coal in thermal power stations gives a lot of benefits in comparison to coal burning only. The properties of fly ash from combustion of fuel mix including 80% of biomass and 20% of bituminous coal were described. Because of significant differences between fly ash tested and conventional fly ash, the ways of its application cannot be indicated without the risk of decrease in durability of concrete due to freezing and thawing. The results of frost resistance test of concrete with fly ash (fab) from co-combustion were presented. The frost resistance was evaluated based on the mass of scaled material related to the concrete surface subjected to 112 cycles of freezing and thawing in the presence of 3% NaCl solution. The statistical analysis of test results indicates that the introduction up to 25% of ground fly ash from co-combustion of biomass and coal to concrete, considering the air-entraining agent and proper curing conditions allows obtaining the durable concrete for structures subjected to external environmental influences.