A Effects of Fiber Types on UHPC Mechanical Properties after High-Temperature Heating and Cooling Method

Seyed Hossein Ghasemzadeh Mousavinejad, Arash Radman, Sepehr Ghorbani GilKalaye — Tue, 06 Aug 2024 00:00:00 +0800

The ultra-high performance concrete (UHPC) is an advanced material that stands out for its remarkable mechanical properties and durability, characterized by an exceptionally high compressive strength. When compared to traditional concrete, UHPC presents itself as a more eco-friendly option with significant potential to enhance the sustainability of infrastructure. This study unveils the mechanical behavior of ultra-high performance fiber reinforced concrete (UHPC) subject to various thermal conditions, incorporating a range of fiber types, both industrial and recycled, in a comprehensive assessment. Furthering the investigation into the influence of high temperatures on UHPC, the research incorporates not only industrially manufactured fibers but also a variety of recycled fibers in the concrete mix, subjecting the samples to intense heating and subsequent cooling regimes. Once the thermal shock is administered, the compressive strength, tensile strength in bending, ultrasonic pulse velocity, and sorptivity of the concrete samples are examined in detail. The findings of this study reveal that the fire resistance of UHPC reinforced with recycled fibers is comparable to that of UHPC reinforced with industrially manufactured fibers. Interestingly, a discernible relationship was observed between the ultrasonic pulse velocity of the samples and their post-temperature strength, suggesting a potential link between these two characteristics.

Numerical Study of GFRP-reinforced Concrete Beams with Straight and Hooked-end Bar Lap Splices

Sara Mirzabagheri, Osama (Sam) Salem — Mon, 01 Apr 2024 00:00:00 +0800

Glass fibre-reinforced polymer (GFRP) has been increasingly used as the main reinforcement in concrete structures due to its durability and resistance to corrosion. However, there is a lack of data regarding the bond behaviour of GFRP bars with 180-degree hooked ends used in flexure concrete elements. To investigate the effects of the hooked ends of GFRP bars on the bond strength with concrete, beams reinforced with GFRP bars with straight and hooked-end lap splices at the midspan were modelled using ABAQUS/Standard software. The finite element models were validated using the experimental results of four full-size concrete beams. Two beam specimens had straight-end bars, while the other two had hooked-end bars. Sensitivity analysis was performed to find the proper values for model verification, such as dilation angle and mesh density. According to the outcomes of the parametric study conducted in this research, changing the length of the bar lap splices in the range of 15 to 40 times the bar diameter had a negligible effect on the beam's overall behaviour. Increasing the number of reinforcing bars from 3 to 5 increased the beam flexural strength by about 33%, whereas increasing the diameter of the bars from 10 to 20 mm doubled the beam strength.

Journal of Building Material Science

A Effects of Fiber Types on UHPC Mechanical Properties after High-Temperature Heating and Cooling Method

Numerical Study of GFRP-reinforced Concrete Beams with Straight and Hooked-end Bar Lap Splices