<p>This study investigates using low-temperature microwave radiation to prepare ultra-high-performance concrete (UHPC), aiming to contribute to sustainable and green concrete technology. Immediate microwave curing (IMC) accelerates the early hardening process, but rapid moisture loss challenges prolonged hydration and strength development. The research combines strength tests, X-ray diffraction, differential thermal analysis and thermogravimetric analysis, scanning electron microscopy with energy dispersive X-ray spectroscopy, and COMSOL simulations to understand these mechanisms.</p><p>The findings reveal that microwaves' unique magnetic effects activate interactions between ions, leading to the formation of atypical phases such as hydrotalcite-like phase (HTlp), calcium silicide (CaSi<sub>2</sub>), and thaumasite-like phase (TSAlp). Unlike delayed microwave curing (DMC), IMC produces crystalline phases such as ettringite, HTlp, TSAlp, and gypsum, while calcium hydroxide (CH)—commonly observed in Portland cement hydration—is absent, reflecting distinct hydration pathways.</p><p>These results suggest that IMC alters the hydration process and microstructure of UHPC. Curing regimes must address moisture retention to ensure sufficient hydration for improved mechanical and microstructural properties to enhance its performance. This study highlights the potential of IMC as a rapid curing method while emphasizing the need for strategies to mitigate its limitations.</p>

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

Application of low-temperature microwave radiation on the preparation of UHPC

  • Xusen Li,
  • Jiarui Wang,
  • Shuangxin Li,
  • Xiaojian Gao,
  • Zhenwu Shi

摘要

This study investigates using low-temperature microwave radiation to prepare ultra-high-performance concrete (UHPC), aiming to contribute to sustainable and green concrete technology. Immediate microwave curing (IMC) accelerates the early hardening process, but rapid moisture loss challenges prolonged hydration and strength development. The research combines strength tests, X-ray diffraction, differential thermal analysis and thermogravimetric analysis, scanning electron microscopy with energy dispersive X-ray spectroscopy, and COMSOL simulations to understand these mechanisms.

The findings reveal that microwaves' unique magnetic effects activate interactions between ions, leading to the formation of atypical phases such as hydrotalcite-like phase (HTlp), calcium silicide (CaSi2), and thaumasite-like phase (TSAlp). Unlike delayed microwave curing (DMC), IMC produces crystalline phases such as ettringite, HTlp, TSAlp, and gypsum, while calcium hydroxide (CH)—commonly observed in Portland cement hydration—is absent, reflecting distinct hydration pathways.

These results suggest that IMC alters the hydration process and microstructure of UHPC. Curing regimes must address moisture retention to ensure sufficient hydration for improved mechanical and microstructural properties to enhance its performance. This study highlights the potential of IMC as a rapid curing method while emphasizing the need for strategies to mitigate its limitations.