scholarly journals Energy Evolution Analysis and Brittleness Evaluation of High-Strength Concrete Considering the Whole Failure Process

Crystals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1099
Author(s):  
Ruihe Zhou ◽  
Hua Cheng ◽  
Mingjing Li ◽  
Liangliang Zhang ◽  
Rongbao Hong
Keyword(s):  
Release Rate ◽  
Elastic Energy ◽  
High Strength Concrete ◽  
Evaluation Method ◽  
Failure Process ◽  
High Strength ◽  
Confining Pressure ◽  
Brittleness Index ◽  
Energy Evolution ◽  
Strength Concrete

In this work, we aimed to solve the problems that exist in the brittleness evaluation method of high-strength concrete through a triaxial compression test of C60 and C70 high-strength concrete. Then, the relationship between the energy evolution of its elastic energy, dissipative energy, pre-peak total energy and additional energy and its axial strain, confining pressure, and concrete strength grade was analyzed. Taking the accumulation rate of pre-peak elastic strain energy and the dissipation rate of dissipative energy, and the release rate of post-peak elastic energy, as the evaluation indicators to characterize the brittleness of high-strength concrete. A brittleness evaluation method that reflects the whole failure process of high-strength concrete is proposed and verified by experiments. The results show that with the increase of the confining pressure, the proportion of elastic energy in the whole process of high-strength concrete failure gradually decreases. The storage rate of pre-peak elastic energy and the release rate of post-peak elastic energy are gradually reducing, the brittleness index gradually decreases, and the confining pressure inhibits the brittleness of high-strength concrete. Under the same confining pressure, the brittleness index of C70 concrete is greater than that of C60 concrete, which indicates that, with the increase of the strength grade, the brittleness level of concrete gradually increases and the ductility decreases. These findings have a certain theoretical significance for the scientific design of high-strength concrete structures and the improvement of their safety in the future.

Comparison of Stress-Strain Relationships of FRP and Actively Confined High-Strength Concrete: Experimental Observations

2014 ◽  
Vol 919-921 ◽  
pp. 29-34 ◽  
Author(s):  
Jian Chin Lim ◽  
Togay Ozbakkloglu
Keyword(s):  
High Strength Concrete ◽  
Axial Stress ◽  
Axial Strain ◽  
High Strength ◽  
Confining Pressure ◽  
Confined Concrete ◽  
Lateral Strain ◽  
Stress Strain ◽  
Strength Concrete ◽  
Actively Confined Concrete

It is well established that lateral confinement of concrete enhances its axial strength and deformability. It is often assumed that, at a same level of confining pressure, the axial compressive stress and strain of fiber reinforced polymer (FRP)-confined concrete at a given lateral strain are the same as those in concrete actively confined concrete. To assess the validity of this assumption, an experimental program relating both types of confinement systems was conducted. 25 FRP-confined and actively confined high-strength concrete (HSC) specimens cast from a same batch of concrete were tested under axial compression. The axial stress-strain and lateral strain-axial strain curves obtained from the two different confinement systems were assessed. The results indicate that, at a given axial strain, lateral strains of actively confined and FRP-confined concretes correspond, when they are subjected to the same lateral confining pressure. However, it is observed that, at these points of intersections on axial strain-lateral strain curves, FRP-confined concrete exhibits a lower axial stress than the actively confined concrete, indicating that the aforementioned assumption is not accurate. The test results indicate that the difference in the axial stresses of FRP-confined and actively confined HSC becomes more significant with an increase in the level of confining pressure.

Study on Durability of C100 Concrete in Shenyang Royal WAN XIN Hotel

2009 ◽  
Vol 405-406 ◽  
pp. 19-23
Author(s):  
Da Li Zhang ◽  
Yuan Wang ◽  
Cui Hong Chen
Keyword(s):  
Mechanical Properties ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
High Strength Concrete ◽  
Evaluation Method ◽  
Chloride Ion ◽  
High Strength ◽  
Test Results ◽  
Strength Concrete

Durability of C100 concrete in Shenyang WAN XIN Hotel engineering including long-term mechanical properties, dynamic modulus of elasticity, and chloride ion resistance was tested and analyzed. Test results appeared that C100 concrete had very good density and extremely good durability. Simultaneously we suggest improving the evaluation method to test the durability of super-high strength concrete in order to enhance the evaluation level effectively. It will provide one according of durability to apply super-high strength concrete.

Seismic Performance and Confinement Reinforcement Design of High-Strength Concrete Columns Confined with High-Strength Stirrups

2021 ◽  
pp. 136943322199249
Author(s):  
Kun Yang ◽  
Qing-xuan Shi ◽  
Qi Lin
Keyword(s):  
Hysteresis Loop ◽  
Axial Compression ◽  
Compression Ratio ◽  
High Strength Concrete ◽  
Failure Modes ◽  
Failure Process ◽  
High Strength ◽  
Effective Measure ◽  
Strength Concrete ◽  
Axial Compression Ratio

This paper aims at analyzing the failure process, failure modes, characteristics of hysteresis loop and the ductility of 10 high-strength concrete (HSC) columns confined by high-strength complex stirrups under cyclic lateral force and a higher constant axial loading. It is indicated that the hysteresis loop of this type of columns still show plump spindle-shaped at higher axial compression ratio, which shows better ductility, energy dissipation and anti-collapse performance. Therefore, it is an effective measure of setting high-strength stirrups to ensure the good ductility of HSC columns under high axial compression ratio and to increase the limit value of axial compression ratio. The stress of transverse reinforcement is evaluated, which shows that high-strength stirrups have yielded when most of the specimens are destroyed, and the strength of stirrups can be fully developed to provide a better effect of restraint. Based on a large number of experimental data, the relationships between the limit drift, the ductility coefficient of HSC columns and axial compression ratio, stirrup characteristic values, covering layer as well as longitudinal reinforcement ratio are established; the calculation formula of minimum stirrups characteristic value of HSC columns at different seismic levels considering of axial compression ratio is presented.

Mechanism of High-strength Concrete Damage Evolution Based on CT Observation

2010 ◽  
Vol 168-170 ◽  
pp. 498-504
Author(s):  
Hui Zhang ◽  
Ren Shu Yang ◽  
Ling Zhao ◽  
Hui Cao
Keyword(s):  
Fractal Dimension ◽  
Release Rate ◽  
Modulus Of Elasticity ◽  
High Strength Concrete ◽  
Damage Evolution ◽  
High Strength ◽  
Negative Temperature ◽  
Damage Factor ◽  
Strength Concrete ◽  
Concrete Damage

To study damage evolution of high-strength concrete under the frozen environment, based on the background of YunCheng auxiliary shaft engineering, this paper studies the damage pattern of C100 concrete under loading by applying the method of industry CT scanning. It aims at showing the evolution process of concrete damage by contrasting of the damage factor on standard curing and negative temperature curing condition, which analyzes the trend of damage modulus of elasticity of C100 high-strength concrete uniaxial compression conditioned from the micro level, combining change of fractal dimension of concrete. The results showed that the change of fractal dimension can reflect the evolution trend of inner damage of concrete, fractal dimension is related with the size of concrete when it damaged. Negative temperature frozen brings about the increase of inner hole of high-strength concrete and decrease of modulus of elasticity, and the ratio of damage energy release rate and strain energy release rate decrease, the energy needed by concrete damage is very low. Moreover, the nonlinear positive correlation between fractal dimension and damage factor of high-strength concrete has been gained.

Study on Strength Development of High Strength Concrete Containing Alccofine and Fly-Ash

2012 ◽  
Vol 2 (3) ◽  
pp. 102-104 ◽  
Author(s):  
Suthar Sunil B ◽  
◽  
Dr. (Smt.) B. K. Shah Dr. (Smt.) B. K. Shah
Keyword(s):  
Fly Ash ◽  
High Strength Concrete ◽  
High Strength ◽  
Strength Development ◽  
Strength Concrete
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