Exploring the Influence of NaOH Catalyst on the Durability of Liquid Calcium Aluminate Cement Concrete

TL;DR

This study examines how different amounts of NaOH affect the durability of a new type of concrete made with liquid calcium aluminate cement.

Contribution

The study introduces a systematic evaluation of NaOH concentration effects on alkali-aggregate reactions and concrete durability in LCAC.

Findings

Higher NaOH concentrations increase alkali-aggregate reactions and concrete porosity.

Chloride ion penetration rises with increased NaOH concentration.

Optimal durability is achieved with 0.5% NaOH concentration.

Abstract

Liquid calcium aluminate cement (LCAC) is an innovative material technology with significant potential for varied applications in civil engineering. However, despite its promising results, a significant gap remains in the direct application of LCAC as a concrete binder. The primary catalysts for LCAC are sodium hydroxide (NaOH) and potassium hydroxide (KOH). Therefore, it is crucial to investigate the effects of sodium and potassium ions on alkali–aggregate reactions in concrete structures. This study evaluated the durability of liquid calcium aluminate cement concrete catalyzed using four different concentrations of NaOH (0.5%, 1.0%, 1.5%, and 2.0%) as experimental variables, incorporating a control group of traditional concrete with a water–cement ratio of 0.64. The findings indicate that NaOH catalysis in the concrete significantly trigger alkali–aggregate reactions, leading to volume expansion. Furthermore, it increased chloride ion penetration and porosity in the concrete. These effects were more notable with the increase in NaOH concentration. The results suggested that NaOH catalysis can enhance certain chemical reactions within the concrete matrix; however, its concentration must be carefully controlled to mitigate adverse effects. The NaOH dosage should be limited to 0.5% to ensure optimal durability of the concrete. This study emphasizes the crucial importance of precisely balancing catalyst concentration to maintain the long-term durability and performance of liquid calcium aluminate cement concrete in structural applications.

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