scholarly journals Influences of Curing Period and Sulfate Concentration on the Dynamic Properties and Energy Absorption Characteristics of Cement Soil

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1291
Author(s):  
Jing-Shuang Zhang ◽  
Xiang-Gang Xia ◽  
Bin Ren

To study the influences of curing period and sulfate concentration on the dynamic mechanical properties of cement soil, this study used a split Hopkinson pressure bar device. Impact tests were conducted on cement soil specimens with different curing periods and different sulfate concentrations. The relationships between the dynamic stress–strain, dynamic compressive strength, and absorption energy of these cement soil specimens were analyzed. The test results show that with continuous loading, cement soil specimens mainly experience an elastic stage, plastic stage, and failure stage; with increasing curing period and sulfate concentration, the dynamic compressive strength and absorption energy of cement soil specimens follow a trend of first increasing and then decreasing. The dynamic compressive strength and absorption energy of cement soil specimens reached maximum values at a curing period of 14 d and a Na2SO4 solution concentration of 9.0 g/L. Increasing the dynamic compressive strength and absorption energy can effectively improve the ability of cement soil specimens to resist damage. This paper provides a practical reference for the application of cement soil in dynamic environments.

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Ronghua Shu ◽  
Tubing Yin ◽  
Xibing Li

Variation in the heating rate due to different geothermal gradients is a cause of much concern in underground rock engineering such as deep sea and underground tunnels, nuclear waste disposal, and deep mining. By using a split Hopkinson pressure bar (SHPB) and variable-speed heating furnace, the dynamic compressive properties of granite were obtained after treatments at different heating rates and temperatures; these properties mainly included the dynamic compressive strength, peak strain, and dynamic elastic modulus. The mechanism of heating rate action on the granite was simultaneously analyzed, and the macroscopic physical properties were discussed. The microscopic morphological features were obtained by scanning electron microscopy (SEM), and the crack propagation was determined by high-speed video camera. The experimental results show that the dynamic compressive strength and elastic modulus both show an obvious trend of a decrease with the increasing heating rate and temperature; the opposite phenomenon is observed for the peak strain. The relationships among the dynamic compressive properties and temperature could be described by the quadratic function. The ductility of granite is enhanced, and the number and size of cracks increase gradually when the heating rate and temperature increase. The microstructure of rock is weakened by the increased thermal stress, which finally affects the dynamic compressive properties of rock.


2013 ◽  
Vol 438-439 ◽  
pp. 215-219 ◽  
Author(s):  
Tao Chen ◽  
Qin Bing Li ◽  
Jun Feng Guan

This paper extends the study of Dharan on the stress state in an elastic solid specimen subjected to axial strain acceleration to compressible materials. And an improved Dharan model is presented. Based on the Drucker-Prager strength criterion, analytical equations of the radial inertia confinement effect on dynamic compressive strength of concrete in split Hopkinson pressure bar tests is derived. Comparison and discussion on the analytical, experimental and numerical results are performed. It is proved that the strain rate effect of compressive strength of concrete materials is a pseudo material property partly caused by the radial inertia confinement. Special attentions should be paid to dynamic tests of low-strength concrete to get the real mechanical properties.


2011 ◽  
Vol 217-218 ◽  
pp. 1811-1816 ◽  
Author(s):  
Chuan Xiong Liu ◽  
Yu Long Li ◽  
Bing Hou ◽  
Wei Guo Guo ◽  
Jin Long Zou

For investigating the effect of temperature on the dynamic properties of concrete material, tests for cylindrical concrete specimens at 23°C ~ 800°C were carried out by using Split Hopkinson Pressure Bar (SHPB) apparatus, and the strain rates ranged from 30/s to 220/s. Effects of temperature and strain-rate on the dynamic behavior of concrete were analyzed. The results show that: above 4000C, the dynamic compressive strength of concrete decreases with increasing temperature, and the enhancements of strain-rates on the compressive strength of concrete depend significantly on temperatures. Moreover, both strain-rate and temperature can enhance the peak strain of concrete.


2018 ◽  
Vol 183 ◽  
pp. 04005 ◽  
Author(s):  
Bar Nurel ◽  
Moshe Nahmany ◽  
Adin Stern ◽  
Nahum Frage ◽  
Oren Sadot

Additive manufacturing by Selective Laser Melting of metals is attracting substantial attention, due to its advantages, such as short-time production of customized structures. This technique is useful for building complex components using a metallic pre-alloyed powder. One of the most used materials in AMSLM is AlSi10Mg powder. Additively manufactured AlSi10Mg may be used as a structural material and it static mechanical properties were widely investigated. Properties in the strain rates of 5×102–1.6×103 s-1 and at higher strain rates of 5×103 –105 s-1 have been also reported. The aim of this study is investigation of dynamic properties in the 7×102–8×103 s-1 strain rate range, using the split Hopkinson pressure bar technique. It was found that the dynamic properties at strain-rates of 1×103–3×103 s-1 depend on a build direction and affected by heat treatment. At higher and lower strain-rates the effect of build direction is limited. The anisotropic nature of the material was determined by the ellipticity of samples after the SHPB test. No strain rate sensitivity was observed.


2018 ◽  
Vol 183 ◽  
pp. 02035 ◽  
Author(s):  
Anatoly Bragov ◽  
Alexander Konstantinov ◽  
Leopold Kruszka ◽  
Andrey Lomunov ◽  
Andrey Filippov

The combined experimental and theoretical approach was applied to the study of high-speed deformation and fracture of the 1810 stainless steel. The material tests were performed using a split Hopkinson pressure bar to determine dynamic stress-strain curves, strain rate histories, plastic properties and fracture in the strain rate range of 102 ÷ 104 s-1. A scheme has been realized for obtaining a direct tensile load in the SHPB, using a tubular striker and a gas gun of a simple design. The parameters of the Johnson-Cook material model were identified using the experimental results obtained. Using a series of verification experiments under various types of stress-strain state, the degree of reliability of the identified mathematical model of the behavior of the material studied was determined.


Sign in / Sign up

Export Citation Format

Share Document