Title:
Feasibility of Using High-alkali Natural Pozzolans and Reclaimed Fly Ash as Alternative Supplementary Cementitious Materials in Concrete
Author(s):
Weiqi Wang
Publication:
Web Session
Volume:
ws_F23_WeiqiWang.pdf
Issue:
Appears on pages(s):
Keywords:
DOI:
Date:
10/29/2023
Abstract:
Increasing shortage of traditional supplementary cementitious materials (SCMs) has necessitated exploring SCMs previously considered less than ideal. This study evaluates the feasibility of using high-alkali SCMs such as a range of high-alkali natural pozzolans, Type S glass, and reclaimed fly ashes, specifically focusing on their role in mitigating concrete alkali-silica reaction (ASR). ASR mitigation performance of SCMs was evaluated using ASTM C1293 (CPT), ASTM C1567 (AMBT), and AASHTO T380 (MCPT). Extracted cement pastes’ pore solution was analyzed to determine the correlation between SCMs’ total and released alkali. Based on this study’s results, most high-alkali SCMs, particularly natural pozzolans, do not release alkalis into pore solution readily and therefore have the potential to offer ASR mitigation when used in sufficient dosage levels. Other concrete durability tests, including sulfate resistance, resistance to chloride ingress, and drying shrinkage, were also conducted on these mixtures, and using high-alkali SCMs was found to be beneficial.