Title: Preparation of Performance-Enhanced Alkali-Activated Slag by Using L-Ascorbic Acid

Author(s): eiyuan Chen, Chunning Pei, Liheng Zhang, Shangkun Li, and Jialai Wang

Publication: Materials Journal

Volume:

Issue:

Appears on pages(s):

Keywords: alkali-activated slag; autogenous shrinkage; complex; L-ascorbic acid; setting time

DOI: 10.14359/51742041

Date: 7/10/2024

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 multi-functional performance-enhancing 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 3d and 28ds increased by 28.9% and 19.6%, respectively, and the 28d autogenous shrinkage decreased by 43.1%. Both surface adsorption and ion complexation have been confirmed as the working mechanisms of LAA in hydrated AAS.