Fabrication of highly porous mortar to alleviate failure caused by alkali-silica reaction (ASR)

¹ Department of Materials Engineering, Faculty of Engineering, Kasetsart University, Bangkok, 10900, Thailand
² Department of Civil Engineering, Faculty of Engineering, Kasetsart University, Bangkok, 10900, Thailand

^a Corresponding author: fengotj@ku.ac.th

Received: 25 August 2016
Accepted: 23 February 2017

Abstract

Alkali-silica reaction (ASR) is one of the crucial mechanism contributing to internal failure of concrete. ASR generally involves formation of swollen alkali silicate hydrate gel, also known as ASR gel, which exerts an expansive pressure, resulting in crack in concrete. This research, hence, aims at inventing porous mortar capable of preventing cracks originated from ASR. In this study, porous mortar bars were successfully fabricated. Aluminium powder, acting as an air entrainment agent, with the concentrations ranging from 0.05 to 0.15 wt% was added to mixture of sand and cement prior to casting. Physical and microstructural examination of the mortar bars revealed that greater quantity of aluminium addition resulted in a higher porosity. Formation of the pores accommodated spaces for ASR gel and reduced the expansive pressure, which potentially led to alleviation of cracks.