Effect of spatial distribution of polymer fibers on preventing spalling of UHPC at high temperatures

Dong Zhang, Yao Zhang, Aravind Dasari, Kang Hai Tan, Yiwei Weng

Research output: Journal article publicationJournal articleAcademic researchpeer-review

29 Citations (Scopus)


Polypropylene (PP) fibers are commonly used for the prevention of thermal spalling of ultra-high performance concrete (UHPC). In this work, the effect of fiber distribution on permeability and spalling resistance is investigated and an analytical model for permeability at 150 °C is proposed. This model, considering the parameters like fiber dimensions, dosage, and percolation, is based on Kozeny-Carman equation. It was found that the percolation of the interconnecting fiber network resulted in a significant increase in permeability of UHPC. X-ray tomography data on the three-dimensional spatial distribution of fibers reiterated that fiber aspect ratio and dosage (and fiber number density) were critical in increasing the fiber connectivity (percolation). It was also found that a vapor permeability of larger than 0.6 × 10−16 m2 at 150 °C could eliminate spalling. Further, based on a semi-empirical approach, aspect ratio between 300 and 600 was recommended for spalling prevention with a fiber dosage of 0.3–0.4 vol%.

Original languageEnglish
Article number106281
JournalCement and Concrete Research
Publication statusPublished - Feb 2021
Externally publishedYes


  • Percolation
  • PP fibers
  • Thermal spalling
  • Ultra-high performance concrete
  • X-ray computer tomography

ASJC Scopus subject areas

  • Building and Construction
  • General Materials Science


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