scholarly journals Experimental Study on the Strength and Deformation Characteristics of Concrete under True Triaxial Compression after Sulfate Attack

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Wei Xia ◽  
Erlei Bai ◽  
Jinyu Xu ◽  
Gaojie Liu
Keyword(s):  
Compressive Strength ◽  
Uniaxial Compressive Strength ◽  
Compression Test ◽  
Triaxial Compression ◽  
Sulfate Attack ◽  
Static Compression ◽  
True Triaxial ◽  
Triaxial Compressive Strength ◽  
Strength And Deformation ◽  
Compressive Strength Of Concrete

To explore the mechanical properties of concrete under true triaxial static compressive load after sulfate attack, uniaxial static compression test and true triaxial static compression test at four stress ratios were carried out on concrete specimens immersed in 15% sulfate solution for 0–120 days by the integrated true triaxial static and dynamic load testing system, and the variation of performance indicators such as the strength and deformation of concrete under the coupling action of sulfate attack and complex stress state was analyzed. The results show that the uniaxial compressive strength of concrete increases at the beginning and then decreases with the increase of sulfate attack time and reaches the peak on the 30th day, with an increase rate of 16.57%; the strength of concrete under triaxial compression increases significantly, and the maximum triaxial compressive strength is 3.18 times of uniaxial compressive strength under the combination of 0-day sulfate attack and 0.2 : 0.8 stress ratio; and the deterioration of concrete under sulfate attack is more prominent at high confining pressure, and as the sulfate attack worsens, the sensitivity of triaxial compressive strength of concrete to lateral compressive stress is reduced. In conclusion, triaxial compression can significantly enhance the ductility of concrete by playing a role in restraining the deformation and cracking of concrete after sulfate attack.

scholarly journals Comparative Analyses Concerning Triaxial Compressive Yield Criteria of Coal with the Presence of Pore Water

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-15 ◽  
Author(s):  
Rulin Liu ◽  
Yanbin Yu ◽  
Weimin Cheng ◽  
Qingfeng Xu ◽  
Haotian Yang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Uniaxial Compressive Strength ◽  
Pore Water ◽  
Yield Criterion ◽  
Triaxial Compression ◽  
Strength Criterion ◽  
Confining Pressure ◽  
Quadratic Polynomial ◽  
Yield Criteria ◽  
Triaxial Compressive Strength

The least absolute deviation is used as a metric to analyze the applicability of five yield criteria, to describe the yield characteristics of coal based on triaxial compressive strength tests on natural, water-saturated, and seepage coal samples with the presence of pore water. The results show that the strength of coal exhibits nonlinear characteristics with the increase of confining pressure, which the linear Coulomb criterion fails to authentically describe. Although the parabolic Mohr criterion can describe the nonlinearity feature more decently than the linear yield criterion, the fitting error is significant, and the uniaxial compressive strength of coal is overestimated. The Hoek-Brown criterion, quadratic polynomial criterion, and exponential criterion yield decent fitting quality for the coal rock. In particular, the exponential strength criterion can accurately reflect the actual uniaxial compressive strength of the rock. However, the differential principle yield stress for an infinite confining pressure calculated from the exponential strength criterion is lower than the measured value. Furthermore, by employing effective stress principle to analyze the yield criteria for the saturated and seepage coal samples, one can find that the quadratic polynomial criterion and the exponential criterion can also reflect the changes of yield characteristics during the fluid-solid coupling triaxial compression test.

scholarly journals Mechanical and Failure Criteria of Air-Entrained Concrete under Triaxial Compression Load after Rapid Freeze-Thaw Cycles

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Feng-kun Cui ◽  
Huai-shuai Shang ◽  
Tie-jun Zhao ◽  
Guo-xi Fan ◽  
Guo-sheng Ren
Keyword(s):  
Compressive Strength ◽  
Uniaxial Compressive Strength ◽  
Stress Ratio ◽  
Triaxial Compression ◽  
Complex Stress State ◽  
Experimental Results ◽  
Testing System ◽  
Freeze Thaw ◽  
Triaxial Compressive Strength ◽  
Air Entrained Concrete

The experiment study on the air-entrained concrete of 100 mm cubes under triaxial compression with different intermediate stress ratioα2=σ2D : σ3Dwas carried out using a hydraulic-servo testing system. The influence of rapid freeze-thaw cycles and intermediate stress ratio on the triaxial compressive strengthσ3Dwas analyzed according to the experimental results, respectively. The experimental results of air-entrained concrete obtained from the study in this paper and the triaxial compression experimental results of plain concrete got through the same triaxial-testing-system were compared and analyzed. The conclusion was that the triaxial compressive strength is greater than the biaxial and uniaxial compressive strength after the same rapid freeze-thaw cycles, and the increased percentage of triaxial compressive strength over biaxial compressive strength or uniaxial compressive strength is dependent on the middle stress. The experimental data is useful for precise analysis of concrete member or concrete structure under the action complex stress state.

scholarly journals Determination of Mechanical Properties of Altered Dacite by Laboratory Methods

Minerals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 813
Author(s):  
Veljko Rupar ◽  
Vladimir Čebašek ◽  
Vladimir Milisavljević ◽  
Dejan Stevanović ◽  
Nikola Živanović
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Rock Mass ◽  
Uniaxial Compressive Strength ◽  
Rock Material ◽  
Strength Parameter ◽  
Gradual Transition ◽  
Strength Parameters ◽  
Triaxial Compressive Strength ◽  
Heterogeneous Rock

This paper presents a methodology for determining the uniaxial and triaxial compressive strength of heterogeneous material composed of dacite (D) and altered dacite (AD). A zone of gradual transition from altered dacite to dacite was observed in the rock mass. The mechanical properties of the rock material in that zone were determined by laboratory tests of composite samples that consisted of rock material discs. However, the functional dependence on the strength parameter alteration of the rock material (UCS, intact UCS of the rock material, and mi) with an increase in the participation of “weaker” rock material was determined based on the test results of uniaxial and triaxial compressive strength. The participation of altered dacite directly affects the mode and mechanism of failure during testing. Uniaxial compressive strength (σciUCS) and intact uniaxial compressive strength (σciTX) decrease exponentially with increased AD volumetric participation. The critical ratio at which the uniaxial compressive strength of the composite sample equals the strength of the uniform AD sample was at a percentage of 30% AD. Comparison of the obtained exponential equation with practical suggestions shows a good correspondence. The suggested methodology for determining heterogeneous rock mass strength parameters allows us to determine the influence of rock material heterogeneity on the values σciUCS, σciTX, and constant mi. Obtained σciTX and constant mi dependences define more reliable rock material strength parameter values, which can be used, along with rock mass classification systems, as a basis for assessing rock mass parameters. Therefore, it is possible to predict the strength parameters of the heterogeneous rock mass at the transition of hard (D) and weak rock (AD) based on all calculated strength parameters for different participation of AD.

scholarly journals Study on the Deterioration of Concrete under Dry–Wet Cycle and Sulfate Attack

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4095
Author(s):  
Fang Liu ◽  
Tonghuan Zhang ◽  
Tao Luo ◽  
Mengzhen Zhou ◽  
Kunkun Zhang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Sodium Sulfate ◽  
Distribution Curve ◽  
Early Stage ◽  
Sulfate Attack ◽  
Industrial Computed Tomography ◽  
Spectrum Distribution ◽  
Compressive Strength Of Concrete ◽  
Internal Pore Structure ◽  
Internal Pore

In order to study the deterioration and mechanism of dry–wet cycles and sulfate attack on the performance of concrete in seaside and saline areas, the deterioration of compressive strength of concrete with different water cement ratios under different erosion environments (sodium sulfate soaking at room temperature and coupling of dry–wet cycling and sodium sulfate) was studied here. At the same time, ICT (industrial computed tomography) and NMR (nuclear magnetic resonance) techniques were used to analyze the internal pore structure of concrete under different erosion environments. The results show that the compressive strength under different erosion environments increases first and then decreases, and the dry–wet cycle accelerates the sulfate erosion. With the increase of dry and wet cycles, larger pores are filled with erosion products and developed into small pores in the early stage of erosion; in the later stage of erosion, the proportion of larger pores increases, and cracks occur inside the sample. In the process of sulfate soaking and erosion, the smaller pores in the concrete account for the majority. As the sulfate erosion continues, the T2 spectrum distribution curve gradually moves right, and the signal intensity of the larger pores increases.

The Experiment to Research the Mudstone Interbeds which Affect the Mechanical Characters of the Layered Rock Salt

2012 ◽  
Vol 226-228 ◽  
pp. 1279-1284
Author(s):  
De Yi Jiang ◽  
Xue Qin Fan ◽  
Tao Ren ◽  
Jie Chen ◽  
Song Ren
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Uniaxial Compressive Strength ◽  
Rock Salt ◽  
Triaxial Compression ◽  
Salt Formation ◽  
Layered Rock ◽  
The Stability ◽  
Mechanic Property ◽  
Mechanical Characters

Since mudstone interlayer has a big influence on the mechanic property of layered rock salt, and in order to research its law, the mudstone which strength is lower than pure rock is used as a interlayer to make the regular layer of salt formation, then both the uniaxial and triaxial compression test are carried out on the layer of salt formation. The result indicates: (1) As the thickness of interlayer increases the uniaxial compressive strength and elastic modulus of layer type salt decrease. (2) On the condition that the thickness of interlayer does not change, the more the interlayer number, the stronger the uniaxial compressive strength. (3) If the total thickness of interlayer is stable and the interlayer number is same, then as the distance of interlayer increases the uniaxial compressive strength and elastic modulus of layer type salt decrease. The result provides practical value and theoretic basis on the further research of the mechanic property of layered rock soil and on the analysis of the stability of Karst underground salt cavity reservoir.

Seafloor Polymetallic Sulfides Mechanical Property Test

2014 ◽  
Vol 1015 ◽  
pp. 316-319
Author(s):  
Zhong Hua Huang ◽  
Shao Jun Liu ◽  
Ying Guang Xu ◽  
Wang Hu
Keyword(s):  
Compressive Strength ◽  
Internal Friction ◽  
Uniaxial Compressive Strength ◽  
Compression Strength ◽  
Triaxial Compression ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Test Method ◽  
Dry Density ◽  
Average Value

Seafloor polymetallic sulfide specimens were developed according to engineering rock test method standard (GB/T 50266-2013). Seafloor polymetallic sulfide wet density and dry density were tested. Uniaxial compressive strength and triaxial compression strength of seafloor polymetallic sulfide were tested using rock mechanics test system MTS 815. Elasticity modulus and Poisson's ratio of seafloor polymetallic sulfide were calculated based on specimens stress-strain curves. Cohesion and internal friction angle were calculated based on specimens triaxial test Mohr stress circle. Test results show that seafloor polymetallic sulfide dry density average value is 2.6 g/cm3, wet density average value is 2.94 g/cm3. Uniaxial compressive strength and triaxial compression strength of seafloor polymetallic sulfide are unstable. Average value of the uniaxial compressive strength is 10.243MPa. Average value of triaxial compression strength test peak load is 47.166KN. Cohesion is 2.447MPa and internal friction angle is 38.04o.

Experimental Study on Mechanical Properties of Jurassic Soft Rock in Shajihai Mining Area of Xinjiang

2013 ◽  
Vol 353-356 ◽  
pp. 20-23
Author(s):  
Xiao Lei Wang ◽  
Shun Xi Yan ◽  
Guang Can Zhang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Compression Test ◽  
Mechanical Test ◽  
Triaxial Compression ◽  
Soft Rock ◽  
Mining Area ◽  
Surrounding Rock ◽  
Test Results ◽  
Support Design

According to the problemsof serious deformation of soft rock roadways and lack of system andcomprehensive study on surrounding rock characteristics and failure mechanismin Shajihai mining area, this paper carried out a series of mechanicalexperiments on the characteristics of surrounding rock in this area includinguniaxial compression test, triaxial compression test and water absorption propertiestest. Mechanical test results show that the compressive strength of surroundingrock of roadway is generally low, and mudstone compressive strength is thelargest which is 19.23 MPa, and compressive strength of the minimum is coalwhich is 11.32 MPa under natural condition. However sandstone and mudstone’sability of water absorbing is strong, and coal saturation strength issignificantly greater than that of mudstone and sandstone. Therefore, we shouldmake full use of the strength of coal in roadway layout and support design.

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