Thermal Induced Microstructural Changes in Calcined Bauxite-Enhanced Ultra-High Performance Concrete

Abstract:

Ultra-High Performance Concrete (UHPC) exhibits exceptional mechanical properties but suffers from significant strength degradation and microstructural deterioration when exposed to elevated temperatures. This study investigates the effectiveness of calcined bauxite as a sustainable material for enhancing the thermal resistance of UHPC. The research focuses on characterizing the microstructural changes in calcined bauxite-enhanced UHPC specimens subjected to thermal treatment at temperatures ranging from 200°C to 600°C. Through comprehensive analyses using scanning electron microscopy (SEM) and Dispersive X-ray Spectroscopy (EDS), the study reveals that the incorporation of calcined bauxite significantly modifies the microstructural evolution of UHPC under thermal exposure. The results demonstrate improved stability of the cementitious matrix, reduced crack formation, and enhanced phase preservation in calcined bauxite-modified UHPC compared to conventional UHPC. The findings provide valuable insights into the microstructural mechanisms responsible for the improved thermal performance and suggest promising applications for calcined bauxite-enhanced UHPC in fire-resistant construction.

• Periodical: Key Engineering Materials (Volume 1060)
• Pages: 137-142
• DOI: https://doi.org/10.4028/p-7thAhi
• Online since: July 2026
• Authors: Nguyen Ngoc Vinh*, Pham Huy Hoa, Nguyen Xuan Thanh, Pham Hong Ngoc, Quang Viet Vu
• Keywords: Calcined Bauxite, Fire Resistance, High-Temperature Performance, Microstructural Changes, Thermal Treatment, Ultra-High Performance Concrete

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