Structural behaviour of novel composite beams consisting of geopolymer concrete and high-performance concrete

Structures ◽  
2021 ◽  
Vol 32 ◽  
pp. 106-115
Author(s):  
Ehsan Nikbakht ◽  
Joel Wong Weng Lok ◽  
Wee Teo
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Composite Beams ◽  
Geopolymer Concrete ◽  
Structural Behaviour

scholarly journals A preliminary study on the development of the normal concrete-UHPC composite beam via wet casting

2021 ◽  
Vol 4 (1) ◽  
pp. 46-56
Author(s):  
Çağlar Yalçınkaya
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Composite Beams ◽  
Absorption Capacity ◽  
Rc Beams ◽  
Tension Zone ◽  
Structural Elements ◽  
Normal Concrete ◽  
Preliminary Study

Ultra-high-performance concrete (UHPC) is an innovative cementitious composite containing steel fiber reinforcement that can improve the behavior of structural elements thanks to its high strength and improved ductility properties. The mix design that provides these superior properties of UHPC also makes it a high-cost material. For this reason, the use of UHPC in parts where it contributes more significantly to the performance of the structural elements will lower down the costs and reduce the negative environmental effects caused by high cement content. In this preliminary study, the production of normal concrete (NC)-UHPC reinforced concrete (RC) composite beams by wet-on-wet casting was investigated by producing mini-RC beams. In the production of mini-RC beams, normal mortar (NM) and self-compacting mortar (SCM) mixtures were used to represent an NC. The results showed that in the production of NC-UHPC composite beams, the mixtures should have different rheological properties depending on the order of the layers. Increasing the total thickness of the UHPC layer enhanced the initial and yield stiffnesses as well as the peak loads. UHPC layer with thicknesses of 15 mm in tension zone, 30 mm in tension zone, and 15+15 mm in tension+compression zone led to the load-carrying capacity increment ratios of 20%, 34.6%, and 24.3%, respectively. However, increasing the thickness of the UHPC layer in the composite beams, especially more than 15 mm, reduced the ductility ratio and energy absorption capacity. Optimizing the tensile reinforcement ratio in UHPC layers can overcome the drawbacks in the ductility.

scholarly journals Structural behaviour of reinforced high performance concrete frames subjected to monotonic lateral loading.

2021 ◽  
Author(s):  
Ali Ehsani Yeganeh
Keyword(s):  
High Performance ◽  
Failure Modes ◽  
Shear Failure ◽  
High Performance Concrete ◽  
Lateral Loading ◽  
Concrete Frames ◽  
Structural Behaviour ◽  
Crack Control ◽  
The Matrix ◽  
Energy Absorbing

This thesis describes the structural performance of reinforced one storey flexural and shear-critical frames made of high performance concretes (HPCs) such as: self-consolidating concrete (SCC), engineered cementitious composite (ECC) and ultra-high performance concrete (UHPC) subjected to monotonic lateral loading. The performance of SCC/ECC/UHPC frames are described based on load-deformation/moment-rotation responses, stiffness, strain developments, crack characterization, failure modes, ductility and energy absorbing capacity. The experimentally obtained moment and shear capacities of the frames are compared with those obtained from Codes and other existing design specifications. Overall, ECC frames showed better performance in terms of higher energy absorbing capacity and ductility compared to SCC/UHPC frames. ECC/UHPC frames showed higher load carrying capacity compared to SCC frames. ECC and UHPC shear-critical frames without shear reinforcement were able to prevent shear failure due to fiber bridging and crack control characteristics contributing to the enhanced shear resistance of the matrix.

scholarly journals Structural behaviour of ultra high performance fibre reinforced concrete composite members

2021 ◽  
Author(s):  
Luaay Hussein
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
High Performance ◽  
Composite Beams ◽  
Shear Capacity ◽  
Fibre Reinforced Concrete ◽  
Test Results ◽  
Structural Behaviour ◽  
Shear Connectors ◽  
High Performance Fibre

The aging and deterioration of reinforced concrete infrastructures in North America present major technical and economical challenges to infrastructure owners. To effectively address some of the challenges, there is a need to develop innovative and cost-effective systems. The main objective of this research was to develop composite members of ultra-high performance fibre reinforced concrete and normal strength concrete or high strength concrete (UHPFRC-NSC/HSC). In order to achieve this objective, the first phase of this research investigates the structural behaviour of UHPFRC with varying fibre content beams without web reinforcement. Test results indicated that the addition of 1% of steel fibres effectively improves the shear strength of UHPC beams by 77% due to the crack-bridging stress that develops across the crack surface. In the second phase, experimental studies were carried out on UHPFRC-NSC/HSC prisms and beams without stirrups to investigate the flexural and shear capacity of those composite members. Each beam specimen was designed to have the UHPFRC layer in tension and the NSC/HSC layer in compression. Additional varied parameters included fibre volume content, and shear connectors were investigated. Test results showed that the performance of the proposed composite system in terms of the flexural and shear capacity was successfully enhanced. All composite beams failed in shear at a force that is 1.6 to 2.0 times higher than that of the NSC/HSC beam's resistance. Test results showed that the effect of using HSC versus NSC in the composite beam was negligible, and the bond strength between the two concrete material layers (UHPFRC and NSC/HSC) was significantly high that the addition of shear connectors was unnecessary. In the third phase, an analytical and finite element models to predict the ultimate shear capacity of UHPFRC composite beams were proposed and validated with the experimental results. The results of the finite element analysis showed that the size effect in structures made of UHPFRC material has little influence on the shear capacity. Finally a comparison between the finite element model and the analytical model indicated that both models developed in this research are capable of predicting the shear behaviour of UHPFRC and UHPFRC-NSC/HSC beams.

Structural Behaviour of Strengthened High-Performance Concrete-Filled Double Skin Steel Tube Beams

2020 ◽  
pp. 87-93
Author(s):  
Ehsan Nikbakht ◽  
Nur Illia Shuhadah ◽  
Ramanathan A/L Ganapathy ◽  
Shukanthi A/P Subramaniam ◽  
Nabilah Abu Bakar
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Steel Tube ◽  
Structural Behaviour ◽  
Double Skin

scholarly journals EXPERIMENTAL AND NUMERICAL ANALYSIS OF FLEXURAL COMPOSITE BEAMS WITH PARTIAL USE OF HIGH STRENGTH/HIGH PERFORMANCE CONCRETE

2005 ◽  
Vol 11 (2) ◽  
pp. 115-120 ◽  
Author(s):  
Andrzej Lapko ◽  
Barbara Sadowska-Buraczewska ◽  
Andrzej Tomaszewicz
Keyword(s):  
Numerical Analysis ◽  
High Performance ◽  
High Performance Concrete ◽  
Concrete Beams ◽  
High Strength ◽  
Composite Beams ◽  
Normal Strength Concrete ◽  
Structural Concrete ◽  
Normal Concrete ◽  
Normal Strength

The paper summarises the experimental and numerical analysis of flexural capacity and deformability of structural concrete beams prepared as composite members consisting of two concrete layers made of reinforced normal concrete and high‐performance concrete (HPC). The reinforced concrete composite beams used in the tests were prepared in full scale with the cross‐section of 120 × 200 mm and the effective span of 2950 mm. The basic samples were composed in two layers consisting of high‐performance concrete as the top layer, and normal strength concrete. The results of the analyses confirm a significant improvement of structural properties of composite beams in comparison to the beams prepared totally of normal concrete, and in some cases also in comparison with the beam totally made of HPC.

scholarly journals Structural behaviour of reinforced high performance concrete frames subjected to monotonic lateral loading.

2021 ◽  
Author(s):  
Ali Ehsani Yeganeh
Keyword(s):  
High Performance ◽  
Failure Modes ◽  
Shear Failure ◽  
High Performance Concrete ◽  
Lateral Loading ◽  
Concrete Frames ◽  
Structural Behaviour ◽  
Crack Control ◽  
The Matrix ◽  
Energy Absorbing

This thesis describes the structural performance of reinforced one storey flexural and shear-critical frames made of high performance concretes (HPCs) such as: self-consolidating concrete (SCC), engineered cementitious composite (ECC) and ultra-high performance concrete (UHPC) subjected to monotonic lateral loading. The performance of SCC/ECC/UHPC frames are described based on load-deformation/moment-rotation responses, stiffness, strain developments, crack characterization, failure modes, ductility and energy absorbing capacity. The experimentally obtained moment and shear capacities of the frames are compared with those obtained from Codes and other existing design specifications. Overall, ECC frames showed better performance in terms of higher energy absorbing capacity and ductility compared to SCC/UHPC frames. ECC/UHPC frames showed higher load carrying capacity compared to SCC frames. ECC and UHPC shear-critical frames without shear reinforcement were able to prevent shear failure due to fiber bridging and crack control characteristics contributing to the enhanced shear resistance of the matrix.

scholarly journals Numerical Modelling of Concrete-to-UHPC Bond Strength

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1379 ◽  
Author(s):  
Alireza Valikhani ◽  
Azadeh Jaberi Jahromi ◽  
Islam M. Mantawy ◽  
Atorod Azizinamini
Keyword(s):  
Bond Strength ◽  
High Performance ◽  
High Performance Concrete ◽  
Experimental Studies ◽  
Structural Behaviour ◽  
Ultra High Performance Concrete ◽  
Direct Tension ◽  
Element Analysis ◽  
Additional Material ◽  
Volume Model

Ultra-High Performance Concrete (UHPC) has been a material of interest for retrofitting reinforced concrete elements because of its pioneer mechanical and material properties. Numerous experimental studies for retrofitting concrete structures have shown an improvement in durability performance and structural behaviour. However, conservative and sometimes erroneous estimates for bond strength are used for numerically calculating the strength of the composite members. In addition, different roughening methods have been used to improve the bond mechanism; however, there is a lack of numerical simulation for the force transfer mechanism between the concrete substrate and UHPC as a repair material. This paper presents an experimental and numerical programme designed to characterize the interfacial properties of concrete substrate and its effect on the bond strength between the two materials. The experimental programme evaluates the bond strength between the concrete substrates and UHPC with two different surface preparations while using bi-surface test and additional material tests, including cylinder and cube tests for compression property, direct tension test, and flexural test to complement UHPC tensile properties. Non-linear finite element analysis was conducted, which uses a numerical zero thickness volume model to define the interface bond instead of a traditional fixed contact model. The numerical results from the zero thickness volume model show good agreement with the experimental results with a reduction in error by 181% and 24% for smooth and rough interface surfaces if compared to the results from the model with a fixed contact.

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