Dynamic splitting behaviour of ultra-high-performance concrete confined with carbon-fibre-reinforced polymer

2022 ◽  
pp. 115155
Liang Huang ◽  
Linwang Su ◽  
Jianhe Xie ◽  
Zhongyu Lu ◽  
Pingjie Li ◽  
2021 ◽  
Vol 54 (1) ◽  
Tobias Dominik Lämmlein ◽  
Janis Justs ◽  
Giovanni Pietro Terrasi ◽  
Pietro Lura

AbstractThe combination of low clinker high-performance concrete (LCHPC) and ultra-high modulus (UHM) carbon fibre reinforced polymer (CFRP) tendons was recently proposed for prestressed structural elements. The 70% reduction in cement content resulting in limited creep and shrinkage of the LCHPC in comparison to a conventional high-performance concrete (HPC) and the very high UHM-CFRP tendon stiffness (> 509 GPa) were expected to impact the mechanical behaviour of such structures. This study focuses on the behaviour of 3 m-long beam specimens during prestressing, concrete hardening and in 4 point-bending experiments. Fibre optic sensors were implemented inside the CFRP tendons to measure strain during those stages and a digital image correlation system was employed to monitor the 4-point-bending tests. After 28 days, the LCHPC recipe, despite a 70% cement reduction and much smaller environmental footprint, did not show measurable differences in the prestress loss behaviour in comparison to a conventional HPC. The UHM-CFRP prestressing tendons, because of their stiffness, showed both higher prestress losses of around 40% and on average a nearly doubled prestress transfer length. However, they increased the beam`s maximum load-bearing capacity by 21% and showed 47% less deflection at failure in comparison to beams prestressed with the standard modulus (UTS)-CFRP tendons.

2000 ◽  
Vol 27 (5) ◽  
pp. 985-992 ◽  
T I Campbell ◽  
N G Shrive ◽  
K A Soudki ◽  
A Al-Mayah ◽  
J P Keatley ◽  

The development of a wedge-type anchorage system for fibre reinforced polymer (FRP) tendons, as part of an overall corrosion-free post-tensioning system, is outlined in this paper. A stainless steel anchor is described, and results from numerical models and load tests to evaluate its behaviour under loads from anchor set, as well as static and repeated tendon tension, are presented. An alternative wedge-type anchorage system made from ultra-high performance concrete is also described. It is shown that, although significant progress has been made in development of the anchorage, further work is required to make it more robust.Key words: FRP tendons, post-tensioning, anchorage, corrosion-free, mathematical models, load tests, concrete.

2021 ◽  
Dave Ametrano

The use of fibre reinforced polymer (FRP) bars is increasing in construction as an alternative to conventional steel rebars. This thesis investigates the bond behaviour of glass fibre reinforced polymer (GFRP) bars embedded in high performance concrete (HPC) and ultra-high performance concrete (UHPC). In this study, the bond characteristics of sand coated GFRP bars embedded in 70-175 MPa concrete were explored. Beam and pullout tests were performed to determine the effects of the concrete strength, bar diameter, embedment length, and concrete cover on the bond behaviour of GFRP bars. Based on the analysis, the development lengths for the GFRP bars were determined and then compared to requirements provided by design codes. It was concluded that the design code lengths could be reduced by 20% while still maintaining a factor of safety of two over the development lengths determined through this study. This reduction can be applied when the GFRP bar is surrounded by sufficient transverse reinforcement, such that adding additional reinforcement would not affect the bond strength. Reducing the amount of GFRP reinforcing material needed, results in a lower overall cost of construction.

2021 ◽  
Chratien Mak

Glass fibre reinforced polymer (GFRP) reinforcements are a viable replacement for corroding steel rebars. GFRP rebar tension lap splices combined with ultra high performance concrete (UHPC) can improve the efficiency of materials and construction in bridge deck construction joints. This thesis investigates the bond performance of high modulus (HM) GFRP rebar splices using UHPC. UHPC slab/beams of 100 -170 MPa concrete having 150 - 300 mm tension splices were tested along with several beams constructed from prefabricated high strength concrete sections with central GFRP spliced UHPC joints. Theoretical analysis was also conducted to evaluate critical splice lengths. Based on comparisons with code design values, recommendations are made on potential failure modes and minimum splice lengths. The serviceability, fatigue, and environmental performance of GFRP in UHPC are also considered. Recommendations from this research will improve the safety and efficiency of GFRP tension lap joints used in bridge decks and other construction

2019 ◽  
Vol 22 (14) ◽  
pp. 3100-3120 ◽  
Jin-Guang Teng ◽  
Yu Xiang ◽  
Tao Yu ◽  
Zhi Fang

Ultra-high-performance concrete is typically defined as an advanced cementitious material that has a compressive strength of over 150 MPa and superior durability. This article presents the development of a new type of ultra-high-performance concrete, namely, ultra-high-performance seawater sea-sand concrete. The development of ultra-high-performance seawater sea-sand concrete addresses the challenges associated with the shortage of freshwater, river-sand and coarse aggregate in producing concrete for a marine construction project. When used together with corrosion-resistant fibre-reinforced polymer composites, the durability of the resulting structures (i.e. hybrid fibre-reinforced polymer–ultra-high-performance seawater sea-sand concrete structures) in a harsh environment can be expected to be outstanding. The ultra-high strength of ultra-high-performance seawater sea-sand concrete and the unique characteristics of fibre-reinforced polymer composites also offer tremendous opportunities for optimization towards new forms of high-performance structures. An experimental study is presented in this article to demonstrate the concept and feasibility of ultra-high-performance seawater sea-sand concrete: ultra-high-performance seawater sea-sand concrete samples with a 28-day cube compressive strength of over 180 MPa were successfully produced; the samples were made of seawater and sea-sand, but without steel fibres, and were cured at room temperature. The experimental programme also examined the effects of a number of relevant variables, including the types of sand, mixing water and curing water, among other parameters. The mini-slump spread, compressive strength and stress–strain curve of the specimens were measured to clarify the effects of experimental variables. The test results show that the use of seawater and sea-sand leads to a slight decrease in workability, density and modulus of elasticity; it is also likely to slightly increase the early strength but to slightly decrease the strengths at 7 days and above. Compared with freshwater curing, the seawater curing method results in a slight decrease in elastic modulus and compressive strength.

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