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 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.

Repair of Severely Damaged Reinforced Concrete Beams with High-Strength Cementitious Grout

2020 ◽  
Vol 2674 (6) ◽  
pp. 372-384
Author(s):  
Antoine N. Gergess ◽  
Mahfoud Shaikh Al Shabab ◽  
Razane Massouh
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Cementitious Materials ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Rc Structures

High-strength cementitious materials such as high-performance concrete are extensively used for retrofit of reinforced concrete (RC) structures. The effectiveness of these materials is increased when mixed with steel fibers. A commonly used technique for strengthening and repair of RC beams consists of applying high-performance fiber-reinforced concrete jackets around the beam perimeter. This paper investigates the jacketing method for repairing severely damaged RC beams. Four 2 m (6 ft 63/4 in.) long rectangular RC beams, 200 × 300 mm (8 ×12 in.) were initially cast and loaded until failure based on three-point bending tests. The four beams were then repaired by thickening the sides of the damaged RC beams using a commercially available high-strength shrinkage grout with and without steel fibers. Strain and deformation were recorded in the damaged and repaired beams to compare structural performance. It is shown that the flexural strength of the repaired beams is increased and the crack pattern under loading is improved, proving that the proposed repair method can restore the resistance capacity of RC beams despite the degree of damage. A method for repair is proposed and an analytical investigation is also performed to understand the structural behavior of the repaired beams based on different thickening configurations.

Study on Volume Stability of High Strengthen High Performance Concrete

2012 ◽  
Vol 204-208 ◽  
pp. 2977-2980
Author(s):  
Run Xia Hao ◽  
Xiao Yan Guo ◽  
Jun Mei Zhao
Keyword(s):  
Volume Change ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Normal Concrete ◽  
Cement Material ◽  
Volume Stability

Volume linearity change rule was found through contrast test of cement material net liquid of adding superfine slag power, high performance concrete and normal concrete. It is guidance significance for volume change of high strength and high performance concrete how to reduce.

The Mechanism of Explosive Spalling and Measures to Resistant Spalling of Concrete Exposed to High Temperature by Incorporating Fibers: A Review

2010 ◽  
Vol 168-170 ◽  
pp. 773-777 ◽  
Author(s):  
Juan Yang ◽  
Gai Fei Peng
Keyword(s):  
High Strength Concrete ◽  
High Performance ◽  
Steel Fiber ◽  
High Performance Concrete ◽  
Polypropylene Fiber ◽  
High Strength ◽  
Hybrid Fiber ◽  
Explosive Spalling ◽  
Preliminary Study ◽  
Experimental Researches

Many experimental researches have been conducted on explosive spalling performance of concrete of high-strength / high performance concrete (HSC/HPC). This paper summarizes two main explosive spalling mechanisms (Vapor pressure build-up mechanism and Thermal stress mechanism) of concrete at elevated temperature, and also presents the measures to resistant the explosive spalling, i.e. by incorporating fibers (polypropylene fiber(PPF), steel fiber(SF) and hybrid fiber of the first two). Finally, the further studies of both the mechanism and the measures are proposed. Also, the preliminary study of ultra high-strength concrete (UHSC) on fire-resistance are mentioned.

scholarly journals Performance Evaluation of High-Strength High-Volume Fly Ash Concrete

2019 ◽  
Vol 8 (3) ◽  
pp. 5990-5994 ◽  
Keyword(s):  
Fly Ash ◽  
Silica Fume ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
High Volume ◽  
Absorption Capacity ◽  
Strength Gain ◽  
Fly Ash Concrete ◽  
High Volume Fly Ash

In the present study, high strength high volume fly ash concrete of M70 grade is developed and its durability properties such as water absorption capacity, porosity, and sorptivityare ascertained. It was found that high volume fly ash does not yield high strength so silica fume is added for early strength gain and for later strength gain lime required for complete pozzolonic action is added to achieve high performance concrete. In this study after testing for various combinations of quaternary blended concrete it was reported that 30% cement +70% fly ash as total powder achieves high strength of nearly 70 MPa, when silica fume of 10% by weight of powder and 30% of lime by weight of powder are added to the total powder content. The high strength high volume concrete developed with this optimum quantities of quaternary blends will be evaluated for the performance.It was found that water absorbtion in high strength high volume fly ash concrete reduced by nearly 85% and porosity is reduced by 34%.

Bestimmung der Dauerhaftigkeit von Hochleistungsbeton mit Hilfe des CDF-Tests / Determination of the durability of high performance concrete by means of CDF-test

1999 ◽  
Vol 5 (1) ◽  
pp. 29-40
Author(s):  
R. Krumbach ◽  
U. Schmelter ◽  
K. Seyfarth
Keyword(s):  
Frost Resistance ◽  
High Strength Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Strength Concrete ◽  
Factors Influencing

Abstract Variable obsen>ations concerning frost resistance of high performance concrete have been made. The question arises which are the decisive factors influencing durability under the action of frost and de-icing salt. The proposed experiments are to be carried out in cooperation with F.A.- Finger - Institute of Bauhaus University Weimar. The aim of this study is to determine possible change of durability of high strength concrete, and to investigate the origin thereof. Measures to reduce the risk of reduced durability have to be found.

scholarly journals Hugoniot Data and Equation of State Parameters for an Ultra-High Performance Concrete

2021 ◽  
Author(s):  
C. Sauer ◽  
F. Bagusat ◽  
M.-L. Ruiz-Ripoll ◽  
C. Roller ◽  
M. Sauer ◽  
...  
Keyword(s):  
Equation Of State ◽  
High Performance ◽  
High Performance Concrete ◽  
Applied Pressure ◽  
High Strength ◽  
Parameter Study ◽  
Ultra High Performance Concrete ◽  
Data Set ◽  
Shock Response ◽  
Particle Velocities

AbstractThis work aims at the characterization of a modern concrete material. For this purpose, we perform two experimental series of inverse planar plate impact (PPI) tests with the ultra-high performance concrete B4Q, using two different witness plate materials. Hugoniot data in the range of particle velocities from 180 to 840 m/s and stresses from 1.1 to 7.5 GPa is derived from both series. Within the experimental accuracy, they can be seen as one consistent data set. Moreover, we conduct corresponding numerical simulations and find a reasonably good agreement between simulated and experimentally obtained curves. From the simulated curves, we derive numerical Hugoniot results that serve as a homogenized, mean shock response of B4Q and add further consistency to the data set. Additionally, the comparison of simulated and experimentally determined results allows us to identify experimental outliers. Furthermore, we perform a parameter study which shows that a significant influence of the applied pressure dependent strength model on the derived equation of state (EOS) parameters is unlikely. In order to compare the current results to our own partially reevaluated previous work and selected recent results from literature, we use simulations to numerically extrapolate the Hugoniot results. Considering their inhomogeneous nature, a consistent picture emerges for the shock response of the discussed concrete and high-strength mortar materials. Hugoniot results from this and earlier work are presented for further comparisons. In addition, a full parameter set for B4Q, including validated EOS parameters, is provided for the application in simulations of impact and blast scenarios.

scholarly journals Abrasion Resistance of Ultra-High-Performance Concrete for Railway Sleepers

2021 ◽  
Author(s):  
Ariful Hasnat ◽  
Nader Ghafoori
Keyword(s):  
Prestressed Concrete ◽  
Abrasion Resistance ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Positive Influence ◽  
Cementitious Material ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Ultra High Performance Concrete

AbstractThis study aimed to determine the abrasion resistance of ultra-high-performance concretes (UHPCs) for railway sleepers. Test samples were made with different cementitious material combinations and varying steel fiber contents and shapes, using conventional fine aggregate. A total of 25 UHPCs and two high-strength concretes (HSCs) were selected to evaluate their depth of wear and bulk properties. The results of the coefficient of variation (CV), relative gain in abrasion, and abrasion index of the studied UHPCs were also obtained and discussed. Furthermore, a comparison was made on the resistance to wear of the selected UHPCs with those of the HSCs typically used for prestressed concrete sleepers. The outcomes of this study revealed that UHPCs displayed excellent resistance against abrasion, well above that of HSCs. Amongst the utilized cementitious material combinations, UHPCs made with silica fume as a partial replacement of cement performed best against abrasion, whereas mixtures containing fly ash showed the highest depth of wear. The addition of steel fibers had a more positive influence on the abrasion resistance than it did on compressive strength of the studied UHPCs.

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