scholarly journals Experimental Study on Influence of Microexpansive Concrete Self-Stress on Performance of Steel Pipe Concrete

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Xin Liu ◽  
Yu-Zhou Zheng ◽  
Qin Fang ◽  
Heng-Bo Xiang ◽  
Hai-Chun Yan
Keyword(s):  
Mechanical Properties ◽  
Uniaxial Compression ◽  
Compression Test ◽  
Steel Tube ◽  
Diameter Ratio ◽  
Expansion Rate ◽  
Uniaxial Compression Test ◽  
Expansive Agent ◽  
Short Columns ◽  
Length To Diameter Ratio

To explore the influence of microexpansive concrete self-stress on the performance of steel pipe concrete, the expansion rate test of microexpansive concrete confined by steel tube was carried out with different expansion rates. Then, the mechanical properties of high-strength steel tube-confined microexpansive concrete (HSTCMC) short columns were conducted by the uniaxial compression test. The length-to-diameter ratio, the expansion rate of the microexpansive concrete, and the steel tube thickness were investigated in the study. Furthermore, the ABAQUS software was employed to analyze the microexpansive mechanism of the concrete, and it was verified by the uniaxial compression test. The test results show that the concrete possesses a remarkable volume expansion phenomenon, which was up to 150 με after four days of maintenance time. The mechanical properties of the HSTCMC short columns were greatly improved compared to the control RC pier. The yield and ultimate strength of the HSTCMC short columns can be enhanced to 8.9% and 14.6%, and with the content of expansive agent that increased from 8% to 12%. The finite element analysis results highlighted that the end constraint at the two ends has the biggest influence on the mechanical performance of the HSTCMC short columns, followed by the thickness of the steel tube and the content of the expansive agent. It should be noted that the self-stress of microexpansive concrete will be decreased with the increase in the length-to-diameter ratio, when the length-to-diameter ratio is less than four. Furthermore, the constraint effect of the circular steel tube on the microexpansive concrete is better than that of the rectangular section steel tube.

scholarly journals Evaluation Method of Granite Multiscale Mechanical Properties Based on Nanoindentation Technology

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Man Lei ◽  
Fa-ning Dang ◽  
Haibin Xue ◽  
Mingming He
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Uniaxial Compression ◽  
Compression Test ◽  
Evaluation Method ◽  
Poisson Ratio ◽  
Nanoindentation Test ◽  
Uniaxial Compression Test ◽  
Displacement Curve ◽  
Mineral Contents

In order to study the mechanical properties of granite at the micro- and nanoscale, the load-displacement curve, residual indentation information, and component information of the quartz, feldspar, and mica in granite were obtained using a nanoindentation test, a scanning electron microscope (SEM), and X-ray diffraction (XRD). The elastic modulus and the hardness of each component of the granite were obtained through statistical analysis. Treating rock as a composite material, the relation between the macro- and microscopic mechanical properties of rock was established through the theory of micromechanical homogenization. The transition from micromechanical parameters to macromechanical parameters was realized. The equivalent elastic modulus and Poisson’s ratio of the granite were obtained by the Self-consistent method, the Dilute method, and the Mori-Tanaka method. Compared with the elastic modulus and the Poisson ratio of granites measured by a uniaxial compression test and the available data, the applicability of the three methods were analyzed. The results show that the elastic modulus and hardness of the quartz in the granite is the largest, the feldspar is the second, the mica is the smallest. The main mineral contents in granite were analyzed using the semiquantitative method by XRD and the rock slice identification test. The elastic modulus and the Poisson ratio of granite calculated by three linear homogenization methods are consistent with those of the uniaxial compression test. After comparing the calculation results of the three methods, it is found that the Mori-Tanaka method is more suitable for studying the mechanical properties of rock materials. This method has an important theoretical significance and practical value for studying the quantitative relationship between macro- and micromechanical indexes of brittle materials. The research results provide a new method and an important reference for studying the macro-, micro-, and nanomechanical properties of rock.

scholarly journals Uniaxial Compression Mechanical Properties of Rock Samples in Soft and Hard Composite Strata

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Bo Wu ◽  
Wei Huang
Keyword(s):  
Mechanical Properties ◽  
Uniaxial Compression ◽  
Compression Test ◽  
Soft Part ◽  
High Strength ◽  
Uniaxial Compression Test ◽  
Strength Ratio ◽  
Rock Samples ◽  
Similar Materials ◽  
The Impact

In the upper soft and lower hard composite strata, it is very difficult to sample the rock and test the mechanical properties of the samples. The study of the mechanical properties of similar material samples by artificial manufacture may enable an alternative method to solve this problem. Therefore, the feasibility of artificial sample preparation and the test of mechanical properties of rock samples in the composite strata become the key to solve the study of mechanical properties of the upper soft strata and the lower hard composite strata. For this purpose, the artificial composite samples composed of two kinds of materials with different strengths were prepared by using cement and kaolin as similar materials. Through the uniaxial compression test of artificial composite rock samples, the effects of the strength ratio of similar materials and the thickness ratio of higher strength materials on the mechanical properties of composite specimens were analyzed. The results of uniaxial compression test show that artificial similar materials could be used to simulate the composite rock samples which are difficult to sample. Without considering the structural interface effect, the greater the strength ratio of similar materials, the greater the impact on the overall strength of composite specimens. The change of volume proportion of high-strength materials has a significant impact on the overall strength of composite specimens. Moreover, the numerical simulation and the experimental stress-strain curves both show a similar trend, indicating that the deformation of the composite strata mainly occurs in the soft part. The research results can provide reference for the test and analysis of mechanical properties in similar complex strata with difficult sampling.

Study on Mechanical Properties of Iron Wire Cement Mortar

2012 ◽  
Vol 594-597 ◽  
pp. 816-819
Author(s):  
Zhi Hao Liu ◽  
Chuan Xiao Liu ◽  
Dong Chen Huang ◽  
Long Wang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Uniaxial Compression ◽  
Compression Test ◽  
Cement Mortar ◽  
Experimental Results ◽  
Uniaxial Compression Test ◽  
Mass Ratio ◽  
Iron Wire

Through the uniaxial compression test, the mechanical properties of different placements of iron wire cement mortar, e.g. compressive strength and elastic modulus, were studied, and the mass ratios of cement, sands and water influencing the mechanical properties were put forward, which provided the experimental results for reference for the wide use of the iron wire cement mortar material. From the study it is gained that: (1) The best placement of the iron wires in cement mortar is horizontal. (2) The best mass ratio of the cement, sands and water is 1:4.70:0.81.

scholarly journals Mechanical properties and X-ray diffraction analyses of clay/sand pellets for CO2 adsorption: the effects of sand content and humidity

2021 ◽  
Vol 76 ◽  
pp. 49
Author(s):  
Isaac Iglesias ◽  
Mayra Jiménez ◽  
Andrea M. Gallardo ◽  
Edward E. Ávila ◽  
Vivian Morera ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Uniaxial Compression ◽  
Compression Test ◽  
Free Fall ◽  
Uniaxial Compression Test ◽  
Sand Content ◽  
X Ray Diffraction ◽  
X Ray

In this work, we report the mechanical properties of an alternative material based on a mixture of natural clay and ferruginous sand in pellet form for CO2 capture. These raw materials were collected from Ecuador, and they contain iron and titanium oxides from volcanic origin. To evaluate the effect of the sand content on the mechanical properties of pellets, the samples were manually prepared with 0 (control sample), 15, and 25 wt.% sand contents and analyzed using free-fall drop impact and uniaxial compression tests. The uniaxial compression test was carried out under three conditions: using sieved sand, using sand without sieving, and under wet conditions. The sand contents caused the drop number to decrease in the free-fall drop impact test. From the uniaxial compression test, the compressive strength, elastic modulus, and toughness were calculated. The elastic modulus showed a better performance for samples with lower porosity. The compressive strength demonstrated higher values for samples with 15 wt.% sand contents than for samples with the other sand contents. The toughness values did not significantly change. It was evidenced that the porosity, mineral composition, and humidity exerted an influence during the mechanical tests. The mineral phases were analyzed by X-ray diffraction, and quantitative analysis based on whole-powder-pattern fitting revealed that the iron and titanium oxide contents increased as the concentration of sand in the pellets increased.

scholarly journals Investigation of Mechanical Properties of Shale Rock in Qassim Region, Saudi Arabia

2019 ◽  
Vol 9 (1) ◽  
pp. 3696-3698
Author(s):  
M. Α. Irfan ◽  
F. A. Almufadi
Keyword(s):  
Mechanical Properties ◽  
Saudi Arabia ◽  
Uniaxial Compression ◽  
Compression Test ◽  
Uniaxial Compression Test ◽  
Schmidt Hammer ◽  
Shale Rock ◽  
Project Match ◽  
Porosity Estimation

An investigation into the mechanical properties of shale rock from Qassim Province, Saudi Arabia is presented in this paper. Uniaxial compression test, Schmidt hammer test and porosity estimation were carried out. Regarding the compression test, it was found that the strength ranged from 1.98MPa to 8MPa and the strain ranged from 0.53% to 2.5%. Regarding the Schmidt Hammer test, it was found that the rebound values ranged from 22.4 to 25. The measurements of volumetric porosity indicated that the porosity in the shale rock ranged between 19.12% and 24.31%. All the values determined in this project match well with the published values of other studies about shale rock.

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