Reaction mechanisms of wood ash for use as a partial cement replacement

Abstract An increase in the produced amounts of wood ashes (WAs) is seen worldwide. In this study, the potential use of two representative WAs as a partial cement replacement is investigated. The WAs originate from combustion of wood chips by grate combustion (WA1) and circulating fluidised bed combustion (WA2). Both WAs were found to possess hydraulic properties, no pozzolanic properties were detected. A substantial difference in strength development was observed between WA1 and WA2 attributed to the phases formed; WA2 contributing the most, ettringite in addition to other phases were formed, while gypsum formed in WA1 pastes.