Biomass Ash in Concrete-Mitigation of Alkali Silica Reactions (ASRs) — Expansions with Different Opal Percentages
ASTM (American Standard Testing and Materials) C 618 prohibits use of biomass ash in concrete. This paper systematically investigates mitigation of Alkali Silica Reaction (ASR) expansion of concrete by three biomass ashes (cement: biomass ash = 65: 35 by weight), and the ASR expansion is triggered by high alkali cement and opal (1-9% weight of quartz replacement). The three biomass ashes come from switchgrass or sawdust cofired with Powder River Basin coal and they cut the ASR expansion significantly below 50% of the control level; however, all three biomass ashes doubled the available alkali of the cement they replaced. Therefore, the exclusion of biomass ash in concrete by ASTM C 618 seems impropriate and more quality research on its role in mitigating ASRs expansion should be conducted.
Jingsi Huo, Yan Xiao, Zongjin Li and Shuaib Ahmad
S. Z. Wang and L. Baxter, "Biomass Ash in Concrete-Mitigation of Alkali Silica Reactions (ASRs) — Expansions with Different Opal Percentages", Key Engineering Materials, Vols. 400-402, pp. 131-136, 2009