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Ultra-high-performance fibre-reinforced concrete is the latest generation of structural concrete, having outstanding fresh and hardened properties; this includes the ease of placement and consolidation with ultra-high mechanical properties, as well as toughness, volume stability, durability, higher flexural and tensile strength, and ductility. As more research is being focused on it, the material behaviour and characteristics are getting more understood, and the research demand for the special applications of the ultra-high-performance fibre-reinforced concrete is growing higher. One special application that ultra-high-performance fibre-reinforced concrete is thought to have an outstanding performance at is in the field of protective structures, specifically against blast loads. This article presents part of a study that is concerned with the behaviour and response of ultra-high-performance fibre-reinforced concrete wall panels under blast load. Size and shape optimization techniques were combined in this study to optimize the design of a 200-MPa ultra-high-performance fibre-reinforced concrete under blast loads using finite element modelling. This design optimization aims to maximize stiffness and minimize the cost while satisfying both design stresses and construction requirements. The design variable to be optimized for are the thickness ranging from 100 to 300 mm at 25 mm increments, in addition to the reinforcement ratio of 0%, 0.2%, 1% and 3%, and aspect ratio of 1, 1.5 and 2; the boundary condition is four edges fixed and restrained. The numerical simulation has been performed using an explicate finite element software package. The complete behaviour of an ultra-high-performance fibre-reinforced concrete is defined using the concrete damaged plasticity model. The concrete constitutive model has been developed considering the contribution of tensile hardening response, fracture energy and crack-band width approaches to accurately represent the tensile behaviour and guarantee mesh independence of results. The blast load is applied using the Conventional Weapons method of the US Army Corps of Engineers that is readily available in the finite element software. The validity of the numerical model used is verified by comparing numerical results to experimental data.

<p>Ultra-High-Performance Fibre Reinforced Concrete (UHP-FRC) is a next-generation concrete with outstanding properties in the fresh and hardened state and superior dynamic properties to traditional concretes. This research focuses on the response of UHP-FRC wall panels under blast loading and presents the advantage of using UHP-FRC over traditional concrete in blast-resistant applications while proposing procedures for the practical analysis and design of UHP-FRC blast protection shields. These objectives are achieved through a two-phased experimental investigation and a comprehensive numerical study.</p> <p> The first phase of the experimental program is conducted at Ryerson University. It includes static four-point load testing on six UHP-FRC one-way panels to investigate the effects of different reinforcement ratios (0%, 1%, and 2%) and fibre volumetric ratios (2% and 3%) on flexural response. The experimental results are used as reference static data for the dynamic shock tube testing. The second phase of the experimental program is conducted at the University of Ottawa using a blast load simulator (shock tube) to investigate the dynamic response of UHP-FRC panels to blast loading. Eight one-way simple supported panels of identical dimensions are tested. The parameters investigated are the steel reinforcement ratio (0%, 1%, and 2%), steel fibre volumetric ratio (2% and 3%), and concrete type (UHP-FRC vs. NSC and HSC). Furthermore, the study provides reference data for the validation of the numerical modelling. The test results showed that UHP-FRC outperformed traditional concrete by showing reduced fragmentation and higher ductility and energy absorption. Experimental results also showed that steel reinforcement is critical to the overall performance of the UHP-FRC panels.</p> <p> The numerical investigation included the development of a new constitutive model suitable for UHP-FRC to be used with the concrete damage plasticity model (CDP) for finite element analysis.  The numerical simulations are performed using the ABAQUS/Explicit[1] numerical platform. The model is validated against the experimental data from the current study and other published data from the literature, yielding good results. The developed numerical model is further used to conduct a comprehensive design optimization study on UHP-FRC wall panels. The parametric study provides guidelines for selecting optimum design parameters for UHP-FRC blast protection panels.  </p>

Glass fiber reinforced polymer (GFRP) bars are used in bridge decks to overcome the problem of corrosion of steel bars and concrete spalling. However, design guidelines for joints between GFRPreinforced precast deck panels supported over girders for accelerated bridge replacement is as yet unavailable. The proposed research investigates the use of GFRP bars in the closure strip between jointed precast deck panels, which is filled with ultra-high performance fiber-reinforced concrete (UHPFRC). Four different bar splice lengths in the joint were considered in this study, namely: 75, 105, 135 and 165 mm, with bar splice spacing taken as 0, 75 and 100 mm. 27 specimens were constructed and tested to-collapse to determine their structural behavior and load carrying capacity. Correlation between experimental findings and available design equations for moment and shear capacities was conducted, leading to recommendations for the use of the proposed joints between precast deck panels in slab-on-girder bridges.

<p>Ultra-High-Performance Fibre Reinforced Concrete (UHP-FRC) is a next-generation concrete with outstanding properties in the fresh and hardened state and superior dynamic properties to traditional concretes. This research focuses on the response of UHP-FRC wall panels under blast loading and presents the advantage of using UHP-FRC over traditional concrete in blast-resistant applications while proposing procedures for the practical analysis and design of UHP-FRC blast protection shields. These objectives are achieved through a two-phased experimental investigation and a comprehensive numerical study.</p> <p> The first phase of the experimental program is conducted at Ryerson University. It includes static four-point load testing on six UHP-FRC one-way panels to investigate the effects of different reinforcement ratios (0%, 1%, and 2%) and fibre volumetric ratios (2% and 3%) on flexural response. The experimental results are used as reference static data for the dynamic shock tube testing. The second phase of the experimental program is conducted at the University of Ottawa using a blast load simulator (shock tube) to investigate the dynamic response of UHP-FRC panels to blast loading. Eight one-way simple supported panels of identical dimensions are tested. The parameters investigated are the steel reinforcement ratio (0%, 1%, and 2%), steel fibre volumetric ratio (2% and 3%), and concrete type (UHP-FRC vs. NSC and HSC). Furthermore, the study provides reference data for the validation of the numerical modelling. The test results showed that UHP-FRC outperformed traditional concrete by showing reduced fragmentation and higher ductility and energy absorption. Experimental results also showed that steel reinforcement is critical to the overall performance of the UHP-FRC panels.</p> <p> The numerical investigation included the development of a new constitutive model suitable for UHP-FRC to be used with the concrete damage plasticity model (CDP) for finite element analysis.  The numerical simulations are performed using the ABAQUS/Explicit[1] numerical platform. The model is validated against the experimental data from the current study and other published data from the literature, yielding good results. The developed numerical model is further used to conduct a comprehensive design optimization study on UHP-FRC wall panels. The parametric study provides guidelines for selecting optimum design parameters for UHP-FRC blast protection panels.  </p>