An investigation of bottom ash as a pozzolanic material

Abstract

Fly ash has been widely used as a pozzolan, but a huge quantity of bottom ash (BA) has been disposed in landfills every year. Therefore, this paper addresses the development and recommendation of using BA as a pozzolanic material. Mortar containing BA at a replacement rate of 20% by weight was used to study the pozzolanic properties. The results showed that the BA needed to have particles retained on a No. 325 (45-µm) sieve at least 25% by weight to achieve the requirements for pozzolan class C and F as specified by ASTM C618. The mortar containing BA from which the particles retained on a No. 325 sieve of 5% by weight produced better compressive strength than control mortar after 28 days. Additionally, BA from several sources had chemical properties favorable for acting as a pozzolanic material. This study’s findings demonstrated that that BA with a proper fineness could be used as a pozzolanic material according to ASTM C618. The utilization of BA is a good solution for the added value, as well as the reduction of BA in landfills.