Title:
Preparation of Performance-Enhanced Alkali-Activated Slag by Using L-Ascorbic Acid
Author(s):
Peiyuan Chen, Chunning Pei, Liheng Zhang, Shangkun Li, and Jialai Wang
Publication:
Materials Journal
Volume:
121
Issue:
5
Appears on pages(s):
105-114
Keywords:
alkali-activated slag (AAS); autogenous shrinkage; complex; L-ascorbic acid (LAA); setting time.
DOI:
10.14359/51742041
Date:
9/1/2024
Abstract:
The applications of alkali-activated slag (AAS) face challenges
such as poor workability, rapid setting, and high autogenous
shrinkage, which require chemical admixtures (CAs) to adjust
the performance of AAS. Unfortunately, there are limited specific
CAs available to tune AAS properties. To address this gap, this
study proposes using a ubiquitous, naturally occurring compound,
L-ascorbic acid (LAA), as a multifunctional performanceenhancing
additive for AAS to overcome the major challenges of
AAS. The findings showed that LAA can function as a retarder,
plasticizer, strength enhancer, and autogenous shrinkage reducer
for AAS. When 0.5% LAA was added, the compressive strengths
of AAS mortars at 3 and 28 days increased by 28.9% and 19.6%,
respectively, and the 28-day autogenous shrinkage decreased by
43.1%. Both surface adsorption and ion complexation have been
confirmed as the working mechanisms of LAA in hydrated AAS.