scholarly journals Flexural Strength Evaluation of Reinforced Concrete Members with Ultra High Performance Concrete

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Baek-Il Bae ◽  
Hyun-Ki Choi ◽  
Chang-Sik Choi
Keyword(s):  
Flexural Strength ◽  
High Performance ◽  
Strain Softening ◽  
Steel Fiber ◽  
High Performance Concrete ◽  
High Strength ◽  
Tension Stress ◽  
Compression Stress ◽  
Ultra High Performance Concrete ◽  
Stress Block

Flexural strength evaluation models for steel fiber reinforced ultra high strength concrete were suggested and evaluated with test results. Suggested flexural strength models were composed of compression stress blocks and tension stress blocks. Rectangular stress block, triangular stress block, and real distribution shape of stress were used on compression side. Under tension, rectangular stress block distributed to whole area of tension side and partial area of tension side was used. The last model for tension side is realistic stress distribution. All these models were verified with test result which was carried out in this study. Test was conducted by four-point loading with 2,000 kN actuator for slender beam specimen. Additional verifications were carried out with previous researches on flexural strength of steel fiber reinforced concrete or ultra high strength concrete. Total of 21 test specimens were evaluated. As a result of comparison for flexural strength of section, neutral axis depth at ultimate state, models with triangular compression stress block, and strain-softening type tension stress block can be used as exact solution for ultra high performance concrete. For the conservative and convenient design of section, modified rectangular stress block model can be used with strain softening type tension stress block.

Mechanical Behavior of UHPC(Ultra High Performance Concrete) According to Hybrid Use of Steel Fibers

2011 ◽  
Vol 287-290 ◽  
pp. 453-457 ◽  
Author(s):  
Gum Sung Ryu ◽  
Su Tae Kang ◽  
Jung Jun Park ◽  
Kyung Taek Koh ◽  
Sung Wook Kim
Keyword(s):  
Flexural Strength ◽  
High Performance ◽  
Steel Fiber ◽  
High Performance Concrete ◽  
Steel Fibers ◽  
Single Type ◽  
Behavioral Characteristics ◽  
Total Rate ◽  
Ultra High Performance Concrete ◽  
Load Bearing Capacity

This intends to examine the flexural behavioral characteristics of hybrid UHPC using a mix of steel fibers with different lengths. Three types of fibers are adopted with fixed diameter of 0.2 mm and lengths of 13, 16.3 and 19.5 mm (aspect ratio of 65, 82 and 98, respectively). Comparative analysis of the flexural strength, load bearing capacity, deflection and toughness is performed adopting a mix use of these 3 types of steel fibers with ratio of 2% and 1.5%. The results show that the hybrid use of steel fibers improves significantly the flexural strength and flexural toughness compared to the use of a single type of fiber. When steel fibers with lengths of 16.3 mm and 19.5mm are admixed at a rate of 1% each, UHPC develops a flexural strength larger by 27% (maximum 50%) than conventional UHPC admixed with 2% of steel fiber with length of 13 mm. Moreover, flexural strength similar to that of conventional UHPC is secured when steel fibers with lengths of 16.3 mm and 19.5mm are admixed at respective rates of 0.5% and 1% (total rate of 1.5%).

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.

Stress-Strain Properties of Engineered Cementitious Composites (ECC) Exposed to Sulfate Dry-Wet Cycle

2020 ◽  
Vol 858 ◽  
pp. 182-187
Author(s):  
Yu Dong Han ◽  
Zhen Bo Wang ◽  
Zi Jie Hong ◽  
Jian Ping Zuo ◽  
Chang Liu ◽  
...  
Keyword(s):  
High Performance ◽  
Strain Softening ◽  
High Performance Concrete ◽  
Cementitious Composites ◽  
Ultra High Performance Concrete ◽  
Stress Strain ◽  
Engineered Cementitious Composites ◽  
Marine Concrete ◽  
New Generation ◽  
Satisfactory Prediction

The brittleness and easiness to crack expose marine concrete to serious durability issues. Engineered Cementitious Composites (ECC), as a new generation of ultra high performance concrete, is expected to overcome the strain-softening properties of traditional concrete and realize function of crack-width control. In this paper, the sulfate erosion of ECC under drying-wetting cycles was modelled in laboratory test. And the compression test on cylinders after exposure to different erosion cycles was implemented to obtain the stress-strain properties. The results disclose that sulfate erosion imposes significant influence on both the nonlinear ascending and descending portions of the stress-strain properties of ECC. As the erosion period extended, ECC strength undergoes an obvious increase. And the descending section of the eroded ECC shows a significant stress drop, which is quite different from that before erosion. Additionally, a simple analytical model was proposed to provide satisfactory prediction of the stress-strain properties of ECC exposed to sulfate erosion.

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