Work

Study on Engineering Geopolymer Composites (EGCs) Under Sustained Thermal Environment: Linking Strain-Hardening Characteristics, Static/Impact Load Mechanical Properties, and Evolution Mechanism

Year: 2025

Type: article

Abstract: This study focuses on the performance evolution of Engineering Geopolymer Composites (EGCs) in long-term thermal environments, investigating the mechanical properties and microstructural evolution of alkali-activated fly ash–slag composites under sustained 60 °C thermal conditions. The research results indicate that sustained exposure to 60 °C significantly enhances the static and impact loading compressive strength of EGCs; however, single-slag or high-alkalinity systems exhibit strength retrogression due to insufficient long-term thermal stability. After exposure to elevated temperatures, the tensile strain-hardening curve of EGCs becomes smoother, with a reduced number of cracks but increased crack width, leading to a transition from a distributed multicrack propagation pattern to rapid widening of primary cracks. Due to the bridging effect of PVA fibers, sustained elevated temperature significantly enhances the peak impact load stress of the S50-6 sample. Microscopic analysis attributes this improvement to the matrix-strengthening effect caused by accelerated C-(A)-S-H gel polymerization and refined pore structure under continuous heat, as well as the energy dissipation role of the fiber system. The study recommends an optimal EGC system formulation with a fly ash–slag mass ratio of 1:1 and a Na2O concentration of 4–6%. This research provides a theoretical foundation for understanding the performance evolution and strength stability of EGC materials under sustained elevated temperature.

Source: Buildings

DOI: 10.3390/buildings15203792

Authors: Shuo Wang, Wei Wang, Haoxing Liu, Ao Huang, Hongqiang Ma

Institution: Hebei University

Language: English

Topic: Concrete and Cement Materials Research

Subfield: Civil and Structural Engineering

Field: Engineering

Domain: Physical Sciences

SDG: Industry, innovation and infrastructure

Open Access status: gold

Estimated APC paid: $3,137