"Leaching behavior and environmental impact of concrete manufactered with biomass ashes"

ABSTRACT: The work described in this paper analyzes the leaching behaviour of a number of concrete specimens made with one type of cement (CEM-II/A-L 32.5 R) and natural aggregates with biomass ash as a supplementary material. The biomass ashes were obtained from a CHP (Combined Heat and Power) plants. The main objective was to study the environmental impact with regard to the leaching potential of the concrete specimen. The biomass ash micro-structure was characterized through Mercury Intrusion Porosimetry (MIP). Dynamic leaching tests were conducted using Italian standard procedure. The heavy metal release resulted in a full conformity to the national legislative requirements. The total ions loss and leachability show a direct relationship with the specific surface area as it is measured by the meso- and micro-pores evaluation using MIP. The total environmental load results were related to the unconfined compressive strength and to the loss on ignition of the biomass employed. These data have been quantified through linear and multiplicative fitting parameters derived from the release curves.