scholarly journals An Experimental Study on the Compressive Dynamic Performance of Rubber Concrete under Freeze-Thaw Cycles

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Juntao Zhang ◽  
Guangli Zhang ◽  
Xinjian Sun ◽  
Wenguo Pan ◽  
Peijie Huang ◽  
...  
Keyword(s):  
Experimental Study ◽  
Elastic Modulus ◽  
Strain Rate ◽  
Compressive Stress ◽  
Dynamic Performance ◽  
Peak Stress ◽  
Engineering Practice ◽  
Stress Strain ◽  
Freeze Thaw ◽  
Rubber Concrete

An experimental study was conducted using a hydraulic servo machine to examine the compressive dynamic performance of rubber concrete under freeze-thaw cycles by considering 4 different numbers of freeze-thaw cycles and 8 different strain rates. The compressive stress-strain curves of rubber concrete under different loading conditions were obtained. By comparatively analyzing the mechanical characteristic parameters of the compressive stress-strain curves (i.e., peak stress, elastic modulus, and peak strain), the following conclusions were drawn: at the same loading strain rate, the compressive peak stress of rubber concrete is gradually decreased while the mass loss rate is gradually increased, as the number of freeze-thaw cycles increases. Compared to ordinary concrete, rubber concrete has a better frost resistance property. At the same number of freeze-thaw cycles, the compressive peak stress and elastic modulus of rubber concrete are gradually increased as the loading strain rate increases. The increase in the number of freeze-thaw cycles enlarges the increasing amplitude of the peak stress and elastic modulus under the action of loading strain rate. The compressive peak stress and elastic modulus dynamic increase factors of rubber concrete exhibit a linear relationship with the dimensionless logarithm of the loading strain rate. Meanwhile, a calculation model was proposed for the compressive peak stress dynamic increase factor of rubber concrete under the coupling effect of freeze-thaw cycles and loading strain rate, and the corresponding stress mechanism was discussed in detail. The research findings are of great significance to the application and development of antifreeze concrete in engineering practice.

scholarly journals EXPERIMENTAL STUDY ON THE DYNAMIC BEHAVIOR OF RUBBER CONCRETE UNDER COMPRESSION CONSIDERING EARTHQUAKE MAGNITUDE STRAIN RATE

2020 ◽  
Vol 26 (8) ◽  
pp. 733-748
Author(s):  
Furong Li ◽  
Yongyi Wu ◽  
Xinghua Xie ◽  
Kai Zhao ◽  
Zhenpeng Yu
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Strain Rate ◽  
Substitution Rate ◽  
Earthquake Magnitude ◽  
Engineering Practice ◽  
Compressive Failure ◽  
Substitution Rates ◽  
Rubber Concrete

To examine the compressive dynamic performance of rubber concrete, a uniaxial compression experimental study on rubber concrete was carried out using a hydraulic servo based on five different rubber substitution rates under eight different earthquake magnitude loading strain rates. The compressive failure modes and stress-strain curves of rubber concrete were obtained. By comparatively analyzing the mechanical characteristics of rubber concrete under different loading conditions, the following conclusions are drawn: with the increase in rubber substitution rate, the integrity of concrete upon compressive failure is gradually improved, and rubber particles exhibit an evident modification effect on cement mortar at the concrete interface. Under the influence of loading strain rate, the patterns of compressive failure mode of rubber concrete with different substitution rates are similar to that of ordinary concrete. Under the same loading strain rate, with the increase in rubber substitution rate, the compressive strength of rubber concrete gradually decreases while the plastic deformation capacity gradually increases. For the same rubber substitution rate, the compressive strength and elastic modulus of rubber concrete gradually increases with the increase in loading strain rate. The increase in rubber substitution rate gradually reduces the increasing amplitude of compressive strength and elastic modulus of rubber concrete under the influence of loading strain rate. Meanwhile, an equation was proposed to describe the coupling effect of rubber substitution rate and strain rate on the compressive strength dynamic increase factor of rubber concrete, and the underlying stress mechanism was further discussed. These results have significance in promoting the application of rubber concrete in engineering practice.

Experimental study on stress-strain curves of seawater sea-sand concrete under uniaxial compression with different strain rates

2020 ◽  
pp. 136943322095876
Author(s):  
Kaijian Zhang ◽  
Jianzhuang Xiao ◽  
Qingtian Zhang
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Strain Rate ◽  
Uniaxial Compression ◽  
Peak Stress ◽  
Ultimate Strain ◽  
Strain Rates ◽  
Peak Strain ◽  
Stress Strain ◽  
Sea Sand

In order to investigate the mechanical properties of seawater sea-sand concrete (SSC) under uniaxial compression, the SSC prisms with different mix proportions are designed and prepared, and the compressive strength and stress-strain curves under uniaxial compression are tested, in which five loading strain rates 10−5/s, 10−4/s, 10−3/s, 10−2/s, and 10−1/s are selected. The failure patterns of the SSC specimens under different strain rates are discussed, and the peak stress, peak strain (strain at the peak stress), elastic modulus, and ultimate strain are analyzed. The influence of the strain rate and the shell particle content on the stress-strain curves is intensively evaluated. It shows that the peak stress and elastic modulus increase with an increasing strain rate while the peak strain and ultimate strain have no obvious trend. Additionally, the shell particles seem to have contributions to the increase of the compressive strength of SSC base on the test results of cube and prism specimens, but further considerations about this phenomenon are necessary. Finally, the dynamic increase factor (DIF) of characteristic indices of SSC is put forward.

scholarly journals Dynamic Characteristics of Sandstone under Coupled Static-Dynamic Loads after Freeze-Thaw Cycles

2020 ◽  
Vol 10 (10) ◽  
pp. 3351
Author(s):  
Bo Ke ◽  
Jian Zhang ◽  
Hongwei Deng ◽  
Xiangru Yang
Keyword(s):  
Energy Absorption ◽  
Dynamic Characteristics ◽  
Shear Failure ◽  
Strain Curve ◽  
Peak Stress ◽  
Peak Strain ◽  
Compression Stress ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Freeze Thaw

The effect of temperature fluctuation on rocks needs to be considered in many civil engineering applications. Up to date the dynamic characteristics of rock under freeze-thaw cycles are still not quite clearly understood. In this study, the dynamic mechanical properties of sandstone under pre-compression stress and freeze-thaw cycles were investigated. At the same number of freeze-thaw cycles, with increasing axial pre-compression stress, the dynamic Young’s modulus and peak stress first increase and then decrease, whereas the dynamic peak strain first decreases and then increases. At the same pre-compression stress, with increasing number of freeze-thaw cycles, the peak stress decreases while the peak strain increases, and the peak strain and peak stress show an inverse correlation before or after the pre-compression stress reaches the densification load of the static stress–strain curve. The peak stress and strain both increase under the static load near the yielding stage threshold of the static stress–strain curve. The failure mode is mainly shear failure, and with increasing axial pre-compression stress, the degree of shear failure increases, the energy absorption rate of the specimen increases first and then decreases. With increasing number of freeze-thaw cycles, the number of fragments increases and the size diminishes, and the energy absorption rates of the sandstone increase.

High Strain-Rate Compressive Behavior and Constitutive Modeling of Selected Polymers Using Modified Ramberg-Osgood Equation

2014 ◽  
Vol 566 ◽  
pp. 80-85
Author(s):  
Kenji Nakai ◽  
Takashi Yokoyama
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Compressive Stress ◽  
Constitutive Modeling ◽  
High Strain ◽  
Strain Rates ◽  
Stress Strain ◽  
Strain Behavior ◽  
Least Squares Fit ◽  
Wide Range

The present paper is concerned with constitutive modeling of the compressive stress-strain behavior of selected polymers at strain rates from 10-3 to 103/s using a modified Ramberg-Osgood equation. High strain-rate compressive stress-strain curves up to strains of nearly 0.08 for four different commercially available extruded polymers were determined on the standard split Hopkinson pressure bar (SHPB). The low and intermediate strain-rate compressive stress-strain relations were measured in an Instron testing machine. Six parameters in the modified Ramberg-Osgood equation were determined by fitting to the experimental stress-strain data using a least-squares fit. It was shown that the monotonic compressive stress-strain behavior over a wide range of strain rates can successfully be described by the modified Ramberg-Osgood constitutive model. The limitations of the model were discussed.

Spall damage of a mild carbon steel: Effects of peak stress, strain rate and pulse duration

2016 ◽  
Vol 660 ◽  
pp. 139-147 ◽  
Author(s):  
C. Li ◽  
B. Li ◽  
J.Y. Huang ◽  
H.H. Ma ◽  
M.H. Zhu ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Strain Rate ◽  
Pulse Duration ◽  
Peak Stress ◽  
Stress Strain ◽  
Mild Carbon Steel ◽  
Spall Damage

AN EXPERIMENTAL STUDY ON THE IMPACT DEFORMATION AND THE STRAIN RATE SENSITIVITY IN SOME STRUCTURAL ADHESIVES

2008 ◽  
Vol 22 (31n32) ◽  
pp. 5590-5595 ◽  
Author(s):  
TOSHIMASA NAGAI ◽  
TAKESHI IWAMOTO ◽  
TOSHIYUKI SAWA ◽  
YASUHISA SEKIGUCHI ◽  
HIDEAKI KURAMOTO ◽  
...  
Keyword(s):  
Strain Rate ◽  
Inelastic Deformation ◽  
Strain Softening ◽  
Peak Stress ◽  
Stress Strain ◽  
Structural Adhesives ◽  
Strain Behavior ◽  
Impact Deformation ◽  
The Impact ◽  
Softening Stage

The impact deformation behavior and the strain sensitivity of structural adhesives are experimentally investigated by using INSTRON-type universal testing machine and split Hopkinson pressure bar apparatus. The experimental results show some fundamental features of the typical compressive stress-strain behavior of polymers with linear elastic and nonlinear inelastic deformation stages. In the inelastic deformation, the peak stress, and the strain-softening stage after the peak can be observed at the entire range of strain-rate from 10-4 to 103 /s. In addition, it can be found that the relationship between the peak stress at the strain-softening stage and strain-rate for a semi-logarithm curve is linear in a range of low strain rate, however, that becomes nonlinear at high strain rate. Finally, some constitutive models try to be applied for to describe the stress-strain behavior of structural adhesives.

scholarly journals Comparative Analysis of Thermomechanical Properties and Thermal Damage Constitutive Models of Three Soft Sedimentary Rocks

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Wenhua Zha ◽  
Weixing Shao ◽  
Suqin Yao ◽  
Qiang Chen ◽  
Denghong Chen
Keyword(s):  
Elastic Modulus ◽  
Thermal Damage ◽  
Sedimentary Rocks ◽  
Soft Rock ◽  
Peak Stress ◽  
Thermomechanical Properties ◽  
Stress Strain ◽  
Soft Rocks ◽  
The Difference ◽  
Sandy Mudstone

In order to study the difference in thermomechanical properties of soft sedimentary rocks of different coal measures, three types of soft sedimentary rocks, sandstone, sandy mudstone, and mudstone, which are common in deep mines, are tested using the RMT-150B rock mechanics test system and GD-65/150. Uniaxial compression experiments were conducted on three kinds of soft rock-cement mixed specimens at 25°C～55°C multistage temperature in an environmental chamber. The difference of important parameters such as stress-strain curve, peak stress, and elastic modulus was analyzed and compared. The results show that (i) in the test temperature range, the stress-strain curves of the three types of soft rocks at different temperatures are roughly divided into four stages: compaction, elasticity, yield, and failure. The proportion of deformation in the compaction stage to the total deformation decreases gradually with the increase of temperature. (ii) When the temperature is lower than 40°C, the yield stage is shorter, and the peak stress and elastic modulus of the three types of soft rocks decrease significantly with the increase of temperature. (iii) Above 40°C, the decreasing trend of peak stress and elastic modulus curve decreases, and the yield stage becomes more and more obvious. The decreasing rate of elastic modulus of sandstone is 0.041 GPa/°C; the decreasing rate of peak stress is 0.193 MPa/°C, the decreasing rate of sandy mudstone is 0.022 GPa/°C and 0.124 MPa/°C, and the decreasing rate of mudstone is 0.020 GPa/°C and 0.051 MPa/°C. (iv) The rationality of the established thermal damage constitutive model of sedimentary soft rock was verified.

Sign in / Sign up

Export Citation Format

Share Document