Concrete and Earthquake Engineering Research Group

Department of Civil & Structural Engineering

Mr Yifan Li

PhD student


Department of Civil and Structural Engineering
Sir Frederick Mappin Building
Mappin Street,
S1 3JD


Personal Profile: Yifan Li is a PhD researcher who joined the CEE Research Group at Sheffield in 2018 after obtaining his MSc degree at University College London in 2017.  He came to the UK in 2013 to study Civil Engineering at Cardiff University and obtained his BEng degree in 2016. Outside research, Yifan is a car enthusiast, but never has the money to buy one! A PC gamer playing a lot of DOTA 2. Likes all kinds of sports, but eats fatty food. He is optimistic and easy going.

Project title: Mitigation of Fire-Induced Spalling of Concrete using Recycled Tyre Fibres

Under extreme circumstances, such as rapid heating, concrete can spall explosively. The propensity of fire spalling is higher for High-Performance Concrete (HPC) than normal concrete, mainly due to its low permeability. Effective spalling mitigation measures include the use of small quantities of micro-polymer fibres, such as polypropylene (PP) fibres. To improve the sustainability of this mitigation method.

Yifan’s research project aims to understand and model the fire spalling mechanism of concrete and develop mitigation methods using recycled tyre fibres. It uses Recycled Tyre Polymer Fibres (RTPF) and Recycled Tyre Steel Fibres (RTSF) as novel substitutions of manufactured PP fibres.


  • Through testing and numerical modelling, understand the mechanism of fire-induced spalling and develop predictive models for fire spalling
  • Improve the cleaning, separation, integration methods of raw recycled fibres
  • Assess the effectiveness of RTPF and RTSF in mitigating fire-induced spalling
  • Determine optimum fibre dosage and optimise concrete mix design for RTPF and RTSF concrete


The project involves experimental work, investigating the fire spalling behaviour of concrete subject to various fire intensities, loading conditions, moisture contents, etc. The project also aims to develop a simplified model that could guide civil engineering practitioners to correctly predict concrete spalling propensity under fire conditions. The model will be developed and validated based on experimental results from macro-scale fire spalling tests and micro-scale neutron scanning tests.

Figure 1           Spalled specimen

Figure 2           Fire spalling test arrangement