Enhancing structural performance of concrete structures with recycled steel fibers through improved mechanical, dynamic, and shear properties

Qin, Xia (2025). Enhancing structural performance of concrete structures with recycled steel fibers through improved mechanical, dynamic, and shear properties. University of Birmingham. Ph.D.

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Abstract

This thesis explores the potential of recycled steel fibres (RSF) as an innovative and environmentally friendly reinforcement material for concrete, addressing the urgent need for cost-effective and sustainable alternatives in the construction industry. RSF, sourced from discarded tires and construction waste, can partially replace industrial steel fibres (ISF), offering benefits such as cost reduction, lower carbon emissions, and enhanced structural strength. This dual advantage not only mitigates environmental pollution but also conserves resources.
The first part of the thesis involves a comprehensive study of the engineering characteristics of RSF, including its mechanical properties, dynamic performance, and structural shear resistance. An essential part of the study is the development of a set of improved shear capacity prediction formulas for high strength steel fibre concrete (HSFRC) beams, based on modifications to the TR63 standard. Additionally, the cradle-to-grave life cycle analysis was conducted to evaluate the carbon footprint of RSF. In the second part, the thesis focuses on modelling and predicting the overall performance of HSFRC beams using experimental data and machine learning techniques. Various machine learning (ML) models were employed to predict key parameters, and finite element modelling (FEM) was used to establish the mechanical behaviour model. Surrogate models were developed to streamline the modelling process, ensuring quick and accurate parameter estimation. With the help of reliable collected experimental database, the study provides a thorough analysis of the reliability of HSFRC beams, offering recommendations to balance safety and economic efficiency. The research also presents a simplified model for assessing the performance of HSFRC beams in corrosive environments, highlighting the material's time-dependent reliability. In summary, RSF emerges as a possible, low-cost, and sustainable substitute for ISF, which has enormous implications for the construction sector.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):