Characterization and properties of elephant grass ashes as supplementary cementing material in pozzolan/Ca(OH)(2) pastes

Abstract

This work presents the behavior of two elephant grass ashes, as pozzolans, elephant grass cameroon (EGC) and napier (EGN), calcined under controlled conditions (700 degrees C). The ashes were initially submitted to a chemical treatment with HCI in order to reduce the potassium content. Both ashes showed high pozzolanic activity after 7 days of curing, with at least 85% of fixed lime. The thermogravimetric and micro-Raman analysis in elephant grass ashes/Ca(OH)(2) pastes confirmed that the main hydrated phases during the pozzolanic reaction consisted of CSH gels, by the weight loss between 60 and 300 degrees C in TG analysis and the band at 680 cm(-1) in Raman spectrums. Based on the achieved results, it is possible to conclude that elephant grass ashes can be used as supplementary cementing materials. (C) 2014 Elsevier Ltd. All rights reserved.