scholarly journals Behavior of Confined Concrete using Prestressing Skew Bars

2022 ◽  
pp. 12-16
Author(s):  
A.M. Elhashimy ◽  
◽  
A. Abbas ◽  
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Modulus Of Elasticity ◽  
Lateral Pressure ◽  
Confined Concrete ◽  
Lateral Strain ◽  
Biaxial Compression ◽  
Compression Behavior ◽  
Initial Modulus ◽  
Confinement Stress

This paper presents the results of an experimental study on the biaxial compression behavior of concrete prism confined using pre-stressed bars. The pre-stressed bars could provide passive confinement stress, that preventing the lateral strain of the prism from increasing leading to an increase in both the initial modulus of elasticity and prism compressive strength. The confined concrete had a higher compressive strength that was directly proportional to the confinement bar pressing force and lower ductility than the plain prisms. The concrete initial modulus of elasticity is directly proportioned to the confinement lateral pressure of the prestressing bar and inversely proportion with the spacing between prestressing bars. It was simple to find out that the best pre-stressing stress was 10 N/mm2, also the compressive strength of the confined concrete with pre-stressed skew bars was greater than the compressive strength of the unconfined concrete by more 3.3 times.

Effect of transverse reinforcement corrosion on compressive strength reduction of stirrup-confined concrete: an experimental study

Sadhana ◽  
2020 ◽  
Vol 45 (1) ◽  
Author(s):  
Ali Goharrokhi ◽  
Jamal Ahmadi ◽  
Mohsen Ali Shayanfar ◽  
Mohammad Ghanooni-Bagha ◽  
Kiarash Nasserasadi
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Strength Reduction ◽  
Confined Concrete ◽  
Transverse Reinforcement ◽  
Reinforcement Corrosion

Experimental Study on Compressive Behavior of CFRP Confined Concrete Columns

2012 ◽  
Vol 446-449 ◽  
pp. 3725-3729
Author(s):  
Wei Hua Ma ◽  
Hong Zhen Kang
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Concrete Strength ◽  
Concrete Columns ◽  
Confined Concrete ◽  
Concrete Column ◽  
Compressive Behavior ◽  
Reinforcing Effect ◽  
Research Results ◽  
Compressive Tests

Compressive tests of 30 concrete column specimens with three concrete strength grades are carried out in this paper to study ultimate compressive strength of specimens. The specimens are divided into three groups, that is, unconfined, confined by CFRP with no initial compression and confined by CFRP with various initial compressions. The different initial compressions’ influence on ultimate stresses and strains are investigated. The decrease of CFRP reinforcing effect due to pre-compression are analyzed. The research results provide experimental datum for reinforced design of existing concrete columns.

Experimental Study of Wet-Screened Aggregate Concrete under Biaxial Compression after Freeze-Thaw Cycles

2011 ◽  
Vol 250-253 ◽  
pp. 3210-3217
Author(s):  
Yu Pu Song ◽  
Xiu Juan Xu
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Life Prediction ◽  
Stress Ratio ◽  
Ultimate Compressive Strength ◽  
Biaxial Compression ◽  
Aggregate Concrete ◽  
Freeze Thaw ◽  
Strain Relationship ◽  
Stress Ratios

Using the static and dynamic triaxial experimental machine, experimental study of the strength of wet-screened aggregate concrete are carried out under biaxial compression stress ratios, 0.25, 0.5, 0.75 and 1 after 0, 50, 100, 150, 200, 250, 300 cycles of freeze-thaw. The change of surface of wet-screened aggregate concrete specimens after different cycles of freeze-thaw are observed and described. The failure characteristic of specimens and the direction of the cracks are also observed. Based on the test data, the influence of freeze-thaw cycles and compressive stress ratio on the ultimate compressive strength and corresponding stress-strain relationship is analyzed respectively. The relationships between the ultimate compressive strength and freeze-thaw cycles, the stress ratios are given, respectively. On this basis, the unified failure criterion with consideration of the influence of freeze-thaw cycles and stress ratio is proposed. It can serve as a reference for the maintenance, design and the life prediction of ocean structures, hydraulic structures, marine structures and offshore platform in cold regions.

Experimental Study on the Effects of Addition of Excessive Volume of Fly Ash on Concrete Properties

2011 ◽  
Vol 99-100 ◽  
pp. 719-722
Author(s):  
Hong Zhu Quan ◽  
Hideo Kasami
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Fly Ash ◽  
Portland Cement ◽  
Modulus Of Elasticity ◽  
Ash Content ◽  
Replacement Ratio ◽  
Aggregate Concrete ◽  
Concrete Properties ◽  
Test Result

This paper presents the results of experimental study on the effects of addition of excessive volume of fly ash on the strength characteristics of concrete. Crushed stone aggregate concrete with the replacement ratio of fly ash to Portland cement of 0, 10%, 20%, 30%, 40%, 60% and 80% were tested for compressive strength and modulus of elasticity at the ages of 7 days, 28 days and 91 days. The test result indicated significant reduction in compressive strength with the increase of fly ash content, indication 90% reduction at 80% fly ash replacement. Reduction in modulus of elasticity was found to be less than those of compressive strength, indicating 60% reduction at 80% fly ash replacement.

Experimental Study of Compression and Carbonation in Concrete Subjected to Freeze-Thaw Environment

2014 ◽  
Vol 887-888 ◽  
pp. 814-818
Author(s):  
Li Xue Wang ◽  
Xiao Ting Shan ◽  
Yu Qing Zhang ◽  
Chun Sheng Li ◽  
Zai Xing Wang ◽  
...  
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
Test Method ◽  
Carbonation Depth ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Freeze Thaw ◽  
Concrete Properties

In order to research the changes of concrete properties in freeze-thaw environment, five concrete samples with water-cement ratio respectively equal to 0.60, 0.65, 0.70, 0.75 and 0.80 were tested in freeze-thaw environment according to GB/T50082-2009 concrete rapid freeze-thaw cycles test method. Five samples were carried out 0, 25, 50, 75, 100 times faster freeze-thaw cycles test. With the increasing number of freeze-thaw cycles, the concrete relative dynamic modulus of elasticity loss rises, the compressive strength drops, and the carbonation depth increases. The greater the water-cement ratio of concrete specimens with freeze-thaw cycles, the greater the degree of damage increases.

An Experimental Study on the Frost Resistance of High Performance Concrete Using Fly-Ash and Agent

2017 ◽  
Vol 904 ◽  
pp. 179-184
Author(s):  
Seung Jo Lee
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Fly Ash ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
Frost Resistance ◽  
High Performance ◽  
High Performance Concrete ◽  
Strength Increase ◽  
Freeze Thaw

The purpose of this study is to investigate the freeze-thaw resistance, one of the most important durability indicators, of high-performance concrete made of fibers (nylon and polypropylene), AE agent, viscosity agent, and fly ash, an industrial by-product. While FN-1 showed the best freeze-thaw resistance with an about 2.8% relative dynamic modulus of elasticity, PV-2 showed the worst results, with an about 7.4% modulus, in comparison tests with GC. Most of the test samples showed better compressive strength than GC. Especially, N-1 showed the greatest compressive strength increase of 8%. Also, the test samples mixed with FA and PP showed a 2-4% compressive strength increase effect.

Compressive behavior of stirrup-confined concrete columns: size effect and a size-dependent stress-strain model

2021 ◽  
pp. 1-63
Author(s):  
Liu Jin ◽  
Ping Li ◽  
Xiuli Du
Keyword(s):  
Compressive Strength ◽  
Size Effect ◽  
Axial Compression ◽  
Axial Stress ◽  
Concrete Columns ◽  
Specimen Size ◽  
Experimental Results ◽  
Confined Concrete ◽  
Compression Behavior ◽  
Strain Model

Numerous studies have indicated the existence of size effect on axial compression behavior of stirrup-confined concrete columns. However, most of these studies have been stressed in terms of nominal compressive strength. The investigation on the size effect of axial strain (at peak load) and descending branch was limited. In this study, the size effect behavior of square stirrup-confined concrete columns under axial compression was explored, by using 3-D mesoscale simulation method. Based on the numerical and available experimental results, the influence of specimen size on the peak axial stress (i.e., the compressive strength), the corresponding strain and the softening rate were explored. Moreover, the quantitative relationships between specimen size and the peak axial stress, the corresponding strain and the softening rate for circular and square stirrup-confined concrete columns were derived. Finally, considering the size effect of peak axial stress, the corresponding strain and the softening rate, a novel stress-strain model describing the axial compression behavior of stirrup-confined concrete was developed. The proposed model was verified by comparing with the available experimental results and the existing models provided.

scholarly journals Experimental study of σ - ε diagrams of concrete under uniaxial compression and the influence of freezing and thawing cycles on the form of the diagrams

2020 ◽  
Vol 17 (4) ◽  
pp. 80-88
Author(s):  
V. M. Popov ◽  
◽  
M. G. Plyusnin ◽  
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Uniaxial Compression ◽  
Reinforced Concrete Structures ◽  
Deformation Characteristics ◽  
Freezing And Thawing ◽  
Coefficients Of Variation ◽  
Initial Modulus ◽  
Compressive Strength Of Concrete ◽  
Freezing And Thawing Cycles

As a result of the experimental study, there was estimated the variability of the form of complete diagrams σ-ε of concrete under uniaxial compression. It is shown that the coefficients of variation of concrete deformation characteristics are comparable with the coefficient of variation of strength within one concrete class in terms of compressive strength. It was found out that the effect of freezing and thawing cycles leads not only to a decrease in the compressive strength of concrete, but also to a decrease in the ultimate deformations and the initial modulus of elasticity. Thus, when using diagram methods for calculating reinforced concrete structures, it is necessary to take into account the influence of variability not only in the strength, but also in the deformation characteristics of concrete.

scholarly journals High-strength flowable mortar reinforced by steel fiber

2011 ◽  
Vol 19 (3) ◽  
pp. 10-16 ◽  
Author(s):  
M. Ramli ◽  
E. Dawood
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Modulus Of Elasticity ◽  
Steel Fiber ◽  
High Strength ◽  
Fiber Content ◽  
Flexural Toughness ◽  
Static Modulus ◽  
Static Modulus Of Elasticity

High-strength flowable mortar reinforced by steel fiberAn experimental study was conducted on High-Strength Flowable Mortar (HSFM) reinforced at different percentages of steel fiber (0, 0.25, 0.5, 0.75, 1.0, 1.25, 1.5, 1.75 and 2.0% as volumetric fractions) to determine the density, compressive strength, static modulus of elasticity and flexural strength. The load-deflection curves under a static flexural load were established, and the flexural toughness indices were obtained in accordance with ASTM C1018. The results indicate that by increasing the fiber content up to 1.75%, the flexural strength and toughness indices are increased. The density, compressive strength and static modulus of elasticity also increased using steel fiber.

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