Development, Material and Structural Performance of Tension Hardening Fiber Reinforced Geopolymer Concrete (THFRGC)

Abstract

On account of growing environmental and economic concerns, decarbonization of the concrete industry has become a priority with the development of environmentally friendly building materials to attract both research community and industry. A class of advanced eco-friendly building materials is geopolymer concretes. Their production incorporates industrial by-products in lieu of cement which has a double benefit in terms of sustainability: recycling industrial wastes instead of harmful disposal and reducing carbon footprint by eliminating cement. Meanwhile, Tension-Hardening Fiber Reinforced Concrete (THFRC) shows great potential as a structural material for modern infrastructure due its enhanced tensile strength and ductility. Although THFRC is considered a sustainable solution thanks to the tension-hardening delaying the need for retrofits, the high amount of Ordinary Portland Cement (OPC) used as a binder raises concerns regarding the sustainability of the material hindering the widespread application on account of the high cost and carbon footprint. This dissertation aims to advance the knowledge on sustainable and high-performance building materials by developing and characterizing a Tension-Hardening Fiber Reinforced Geopolymer Concrete (THFRGC) in terms of its material and structural behaviour. After a thorough review of the related literature, the experimental stage comprises the characterization of various mineral powders, mix design based on chemical and physical optimization, material identity characterization according to North American Standards prescribed for conventional THFRCs, determination of bond-slip law of reinforcing bar in THFRGC and performance under biaxial stress states. To promote the widespread use of the material, rheology, and fiber orientation in THFRCs are also explored using destructive and non-destructive techniques. Furthermore, this project aims to tackle the conundrum of tensile characterization of THFRC by developing a novel indirect tension technique that combines the simplicity of splitting test with the ability to obtain the whole response in pure tension. The proposed test is numerically validated using advanced Non-Linear Finite Element Analysis. The latter was also employed to investigate the validity of the tensile response obtained using the Inverse Analysis proposed by CSA, S6, Annex 8.1. Finally, self-sensing performance of a multifunctional nanoengineered THFRC is explored to pave the way for smart THFRCs in Structural Health Monitoring (SHM) applications.