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Abstract

Ultra-high-Performance concrete (UHPC) is a cementitious composite material that is newly introduced to modern construction. Steel fibres are commonly added to the mix to improve the mechanical properties of the Ultra high-performance concrete. In such Ultra-high-performance fibre reinforce concrete (UHPFRC) can achieve compressive strengths beyond 120 MPa. Much needed testing is required to investigate the mechanical properties of this material. This study is mainly focused on exploring the elastic behaviour of this material. Thus, this study investigated the effects of steel fibre on the modulus of elasticity and Poisson ratio as these are considered the core mechanical properties of this concrete. To examine the modulus of elasticity of this concrete, Ultrasonic pulse velocity (UPV), a type of non-destructive testing (NDT) technique, was used. Ultrasonic pulse velocity test offers an easy alternative and economic advantages over static testing that needs to be further exploited. The reliability of the NDT’s is often varied; therefore, the study’s purpose was to measures the reliability of the UPV results by comparing them against static results. The static and dynamic results were compared to identify differences between the static and dynamic modulus of elasticity. The study uses the control variable of three prism samples containing 2%, 4%, and 6% steel fibre content. The samples were tested using Ultrasonic transducers for compressive waves at direct and indirect set up to determine the reliability of UPV results. 1Mhz frequency was set as the constant frequency for propagating waves within the different prism samples. The quality of the concrete samples was also determined through UPV tests. Static values were obtained after concrete samples gained their max compressive strength. Empirical equations were studied to investigate static and dynamic modulus of elasticity. Results were displayed in a linear graphical format to show correlations between 2%, 4 % and 6% fibre content samples. A strong correlation between dynamic and static modulus of elasticity was found with the increased fibre content of the specimens. Results found for dynamic tests and empirical equations were compared to static results were discovered to be closely established. Limitations in empirical equations were also discovered. A strong correlation between the Poisson ratio and modulus of elasticity was found.

Course: Civil Engineering - MSc - C0618

Date Deposited: 2022-03-28

URI/permalink: https://library.port.ac.uk/dissert/dis13869.html