Work

Effects of superabsorbent polymers on autogenous shrinkage and microstructure in metakaolin-based cementitious materials

Year: 2025

Type: article

Abstract: The use of superabsorbent polymers (SAPs) in combination with supplementary cementitious materials like metakaolin presents an opportunity to enhance concrete performance while addressing environmental concerns in construction, lowering CO2 emissions by clincker substitution. This study investigates the behavior of high-strength microconcrete incorporating SAPs and metakaolin, evaluating their feasibility and sustainability for construction applications. Three microconcrete and paste mixes were analyzed: a reference mix and two mixes containing 0.15% and 0.30% SAP by cement mass. All mixes included a 10% metakaolin substitution by cement mass and maintained the same water/cement ratio, without additional curing water for SAPs. Fresh-state tests assessed consistency and specific mass, while hardened-state tests measured elastic modulus. Autogenous shrinkage was evaluated through linear volumetric variation using dial gauges. Microstructural analysis of the pastes and microconcretes involved thermogravimetry, isothermal conduction calorimetry, and X-ray microtomography. The results highlight the beneficial effects of SAPs with metakaolin, including enhanced hardened state properties and refined pore structure, achieved despite the absence of extra curing water. SAPs contributed to increased pozzolanic activity in metakaolin, likely due to delayed water release from SAP desorption. Furthermore, SAPs effectively mitigated autogenous shrinkage, making their application in concrete mixes promising. These findings emphasize the dual benefit of improving concrete performance and advancing environmental sustainability, showcasing the potential of SAPs and metakaolin in producing high-performance, eco-friendly concrete solutions for the construction industry.

Source: Case Studies in Construction Materials

DOI: 10.1016/j.cscm.2025.e04740

Authors: Arthur Aviz Palma e Silva, Valdirene Maria Silva Capuzzo, Eugênia Fonseca da Silva, André Maués Brabo Pereira, Lívia Borba Agostinho

Language: English

Topic: Concrete Properties and Behavior

Subfield: Civil and Structural Engineering

Field: Engineering

Domain: Physical Sciences

SDGs: Responsible consumption and production, Climate action

Open Access status: gold

Estimated APC paid: $2,660