A rutting prediction method for semi-rigid pavement structures using accelerated loading tests and finite element analysis was proposed in this study. Firstly, dynamic modulus and creep tests of three pavement materials were performed by changing sizes and temperatures. The prediction equation was obtained and verified using the falling weight deflectometer test and back-calculation modulus, and it was coupled into a modified Burgers model for rutting simulation for full-scale pavement structures. Results showed that the dynamic modulus of pavement materials increased with increasing specimen sizes and decreased with increasing temperature. SUP-25 had an enormous fatigue damage value (0.419) after 5,400 times repeated loading. The error between the rutting simulation and test results was 2.87 %, indicating that the model effectively applies to multilayer composite materials. Rutting deformation at one million loading times in summer was 4.6 times that in winter. From 22 to 120 km/h, rutting deformation decreased by 72.6 %. Axle load increased by 100 %, and rutting depth increased by 46.9 %, indicating that vehicle overload should be restricted, especially in low-speed sections in high-temperature areas. Rutting deformation entered the accelerated accumulation stage when the cumulative action times were more than 25 million, which requires timely maintenance and repair of pavement structures.
{"title":"Permanent Deformation Evaluation and Instability Prediction of Semi-rigid Pavement Structure Using Accelerated Pavement Testing and Finite Element Method","authors":"Zhen Liu, Xingyu Gu, Qiao Dong","doi":"10.1520/jte20230209","DOIUrl":"https://doi.org/10.1520/jte20230209","url":null,"abstract":"A rutting prediction method for semi-rigid pavement structures using accelerated loading tests and finite element analysis was proposed in this study. Firstly, dynamic modulus and creep tests of three pavement materials were performed by changing sizes and temperatures. The prediction equation was obtained and verified using the falling weight deflectometer test and back-calculation modulus, and it was coupled into a modified Burgers model for rutting simulation for full-scale pavement structures. Results showed that the dynamic modulus of pavement materials increased with increasing specimen sizes and decreased with increasing temperature. SUP-25 had an enormous fatigue damage value (0.419) after 5,400 times repeated loading. The error between the rutting simulation and test results was 2.87 %, indicating that the model effectively applies to multilayer composite materials. Rutting deformation at one million loading times in summer was 4.6 times that in winter. From 22 to 120 km/h, rutting deformation decreased by 72.6 %. Axle load increased by 100 %, and rutting depth increased by 46.9 %, indicating that vehicle overload should be restricted, especially in low-speed sections in high-temperature areas. Rutting deformation entered the accelerated accumulation stage when the cumulative action times were more than 25 million, which requires timely maintenance and repair of pavement structures.","PeriodicalId":17109,"journal":{"name":"Journal of Testing and Evaluation","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135131259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bingxiang Yuan, Jingkang Liang, Hengzheng Lin, Wanying Wang, Yao Xiao
Leakage associated with deformation joints seriously affects tunnel structures. Existing tunnel deformation joint waterproofing structures have high construction costs and inconvenient maintenance requirements. This work proposes a new tunnel deformation joint waterproofing structure. Specifically, this structure combines Ω type water stop, an externally attached water stop, and a concrete component. An impermeability test compares standard waterproofed specimens to improved specimens. Under a variety of deformation joint widths, fatigue loading times, and displacement difference, the variation law of the seepage quantity and impermeability pressure values are obtained. The study also examined the ability of the waterproofing membrane and waterproofing coating to improve on standard practices currently used. The seepage quantity test results indicate a positive correlation of displacement difference and fatigue loading times with seepage quantity. The larger the deformation joint width of the specimen, the more the new construction process demonstrated its ability to resist high fatigue loading times and large displacement differences. As the fatigue loading times increase, the impermeability pressure value of both types of specimens decrease; however, the impermeability pressure value of the improved specimen was less affected, which verifies an increased fatigue resistance. Both waterproofing membranes and waterproofing coatings improve the waterproofing ability of the standard specimen, while the impermeability law demonstrated similar results to the standard process specimen. Ultimately, these findings reveal the value of selecting appropriate deformation joint widths under different practical engineering conditions.
{"title":"Experimental Study on Influencing Factors Associated with a New Tunnel Waterproofing for Improved Impermeability","authors":"Bingxiang Yuan, Jingkang Liang, Hengzheng Lin, Wanying Wang, Yao Xiao","doi":"10.1520/jte20230417","DOIUrl":"https://doi.org/10.1520/jte20230417","url":null,"abstract":"Leakage associated with deformation joints seriously affects tunnel structures. Existing tunnel deformation joint waterproofing structures have high construction costs and inconvenient maintenance requirements. This work proposes a new tunnel deformation joint waterproofing structure. Specifically, this structure combines Ω type water stop, an externally attached water stop, and a concrete component. An impermeability test compares standard waterproofed specimens to improved specimens. Under a variety of deformation joint widths, fatigue loading times, and displacement difference, the variation law of the seepage quantity and impermeability pressure values are obtained. The study also examined the ability of the waterproofing membrane and waterproofing coating to improve on standard practices currently used. The seepage quantity test results indicate a positive correlation of displacement difference and fatigue loading times with seepage quantity. The larger the deformation joint width of the specimen, the more the new construction process demonstrated its ability to resist high fatigue loading times and large displacement differences. As the fatigue loading times increase, the impermeability pressure value of both types of specimens decrease; however, the impermeability pressure value of the improved specimen was less affected, which verifies an increased fatigue resistance. Both waterproofing membranes and waterproofing coatings improve the waterproofing ability of the standard specimen, while the impermeability law demonstrated similar results to the standard process specimen. Ultimately, these findings reveal the value of selecting appropriate deformation joint widths under different practical engineering conditions.","PeriodicalId":17109,"journal":{"name":"Journal of Testing and Evaluation","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135133213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhengzhen Wang, Lei Huang, Guoliang Dai, Feng Li, Tianzhong Ma
To study the grouting effect of pile end and pile side combined post-grouting technology in cohesive soil, the self-balancing static load test was carried out on two bored piles with length of 56.5 m and diameter of 1.5 m in a bridge pile foundation project, and the test results before and after the combined cement grouting were compared and analyzed. The influences of combined grouting on ultimate load-bearing ability, pile axial force, pile side friction, pile end resistance, and settlement reduction of bored piles in cohesive soil were studied. The findings revealed that the ultimate load-bearing abilities of combined grouting piles in cohesive soil improved by 32.99∼38.42 % as compared with before grouting, the corresponding settlement was effectively controlled, and the grouting effect was remarkable. Combined post-grouting enhanced the soil layer strengths of pile tip soil and pile side soil, improved the condition of pile-soil contact surface, and greatly increased the pile end resistance and pile side friction. The pile end resistances increased by 96.90∼98.61 % and pile side frictions increased by 23.63∼29.70 %, which causes the pile axial force to decay faster along the piles and also has an obvious influence on load transfer characteristic of the test piles. However, in some stages, the reinforcement effect of post-grouting on the soil stiffness of pile side was not obvious or even deteriorated, which reflected the instability of the reinforcement effect of post-grouting technology.
{"title":"Experimental Study on Grouting Effect of Combined Post-Grouting Piles in Cohesive Soil","authors":"Zhengzhen Wang, Lei Huang, Guoliang Dai, Feng Li, Tianzhong Ma","doi":"10.1520/jte20230341","DOIUrl":"https://doi.org/10.1520/jte20230341","url":null,"abstract":"To study the grouting effect of pile end and pile side combined post-grouting technology in cohesive soil, the self-balancing static load test was carried out on two bored piles with length of 56.5 m and diameter of 1.5 m in a bridge pile foundation project, and the test results before and after the combined cement grouting were compared and analyzed. The influences of combined grouting on ultimate load-bearing ability, pile axial force, pile side friction, pile end resistance, and settlement reduction of bored piles in cohesive soil were studied. The findings revealed that the ultimate load-bearing abilities of combined grouting piles in cohesive soil improved by 32.99∼38.42 % as compared with before grouting, the corresponding settlement was effectively controlled, and the grouting effect was remarkable. Combined post-grouting enhanced the soil layer strengths of pile tip soil and pile side soil, improved the condition of pile-soil contact surface, and greatly increased the pile end resistance and pile side friction. The pile end resistances increased by 96.90∼98.61 % and pile side frictions increased by 23.63∼29.70 %, which causes the pile axial force to decay faster along the piles and also has an obvious influence on load transfer characteristic of the test piles. However, in some stages, the reinforcement effect of post-grouting on the soil stiffness of pile side was not obvious or even deteriorated, which reflected the instability of the reinforcement effect of post-grouting technology.","PeriodicalId":17109,"journal":{"name":"Journal of Testing and Evaluation","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135133207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Muralimohan, U. N. Kempaiah, G. B. Veeresh Kumar
The remarkable characteristics of aluminum alloys, like their hardness, strength-to-weight ratio, fatigue, corrosion resistance, play a decisive role in the aeronautical and automotive industries. However, scientists are on the lookout for substantial advancements in the wear resistance of the composites under varied service situations. This investigation focuses on the characteristics of hybrid metal matrix composites with regards to optical, physical, mechanical, tribological, and corrosion behavior of ADC12 alloy reinforced by born carbide and rice husk ash (RHA) particulates. The liquid metallurgy process with the stir casting technique was used to produce the hybrid composites, which were then compared to monolithic materials. In the fabrication, reinforcement RHA was added from 0 to 12 % while maintaining a born carbide content of 5 %. Following ASTM standards, the resulting composites were put through optical, several physical, mechanical, wear, and corrosion testing. The experimental findings were then analyzed. With a rise in the amount of reinforcement in the base alloy, physical and mechanical characteristics greatly improved, whereas the percentage of elongation was seen to decline. The effects of exposure time were studied on the hybrid composites on corrosion behavior in acidic environments. The composites are exposed to the hydrochloric acid solution, and weight loss over various periods, from 12 to 72 h, is measured in steps of 12 h. It was discovered that the corrosion resistance increased as the reinforcing content increased. By using a pin-on-disc apparatus, the wear tests were conducted, and the outcomes indicated the composites’ superior wear resistance. Composites with a higher percentage of reinforcement displayed superior characteristics. Following the tensile testing, broken surfaces, wear, and corrosion morphology are examined in scanning electron microscope images. The research findings are thoroughly examined, and careful interpretations have been made.
{"title":"Characterization of Born Carbide and Rice Husk Ash Reinforced Aluminum Alloy Composites","authors":"R. Muralimohan, U. N. Kempaiah, G. B. Veeresh Kumar","doi":"10.1520/jte20230201","DOIUrl":"https://doi.org/10.1520/jte20230201","url":null,"abstract":"The remarkable characteristics of aluminum alloys, like their hardness, strength-to-weight ratio, fatigue, corrosion resistance, play a decisive role in the aeronautical and automotive industries. However, scientists are on the lookout for substantial advancements in the wear resistance of the composites under varied service situations. This investigation focuses on the characteristics of hybrid metal matrix composites with regards to optical, physical, mechanical, tribological, and corrosion behavior of ADC12 alloy reinforced by born carbide and rice husk ash (RHA) particulates. The liquid metallurgy process with the stir casting technique was used to produce the hybrid composites, which were then compared to monolithic materials. In the fabrication, reinforcement RHA was added from 0 to 12 % while maintaining a born carbide content of 5 %. Following ASTM standards, the resulting composites were put through optical, several physical, mechanical, wear, and corrosion testing. The experimental findings were then analyzed. With a rise in the amount of reinforcement in the base alloy, physical and mechanical characteristics greatly improved, whereas the percentage of elongation was seen to decline. The effects of exposure time were studied on the hybrid composites on corrosion behavior in acidic environments. The composites are exposed to the hydrochloric acid solution, and weight loss over various periods, from 12 to 72 h, is measured in steps of 12 h. It was discovered that the corrosion resistance increased as the reinforcing content increased. By using a pin-on-disc apparatus, the wear tests were conducted, and the outcomes indicated the composites’ superior wear resistance. Composites with a higher percentage of reinforcement displayed superior characteristics. Following the tensile testing, broken surfaces, wear, and corrosion morphology are examined in scanning electron microscope images. The research findings are thoroughly examined, and careful interpretations have been made.","PeriodicalId":17109,"journal":{"name":"Journal of Testing and Evaluation","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135133214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The effects moisture content and temperature are important in microwave measurements and building material engineering. In this article, the relationship between the effects of moisture content/temperature and microwave measurements of lightweight foamed concrete is investigated. A frequency sweep measurement from 150 kHz to 8 GHz was performed on 10-cm cube samples with varying moisture content (0–20 %) and temperature (20°C–40°C). The microwave S-parameters were measured using an R&S ZVB8 Vector Network Analyzer with an N-type open-ended coaxial sensor and were used to calculate the dielectric constant. Models were developed to describe the relationship between moisture content, temperature, and dielectric characteristics of the concrete. Validation showed that the error was below 5 % for dielectric constant and below 8 % for loss factor at 5-GHz frequency. These findings have implications for the telecommunications industry and on-site moisture content measurements, with potential applications in building material engineering.
{"title":"Effects of Moisture Content and Temperature on Microwave Measurement of Lightweight Foamed Concrete","authors":"Kim-Yee Lee, Yeong-Nan Phua, Siong-Kang Lim, Kok-Yeow You, Ee Meng Cheng","doi":"10.1520/jte20230257","DOIUrl":"https://doi.org/10.1520/jte20230257","url":null,"abstract":"The effects moisture content and temperature are important in microwave measurements and building material engineering. In this article, the relationship between the effects of moisture content/temperature and microwave measurements of lightweight foamed concrete is investigated. A frequency sweep measurement from 150 kHz to 8 GHz was performed on 10-cm cube samples with varying moisture content (0–20 %) and temperature (20°C–40°C). The microwave S-parameters were measured using an R&S ZVB8 Vector Network Analyzer with an N-type open-ended coaxial sensor and were used to calculate the dielectric constant. Models were developed to describe the relationship between moisture content, temperature, and dielectric characteristics of the concrete. Validation showed that the error was below 5 % for dielectric constant and below 8 % for loss factor at 5-GHz frequency. These findings have implications for the telecommunications industry and on-site moisture content measurements, with potential applications in building material engineering.","PeriodicalId":17109,"journal":{"name":"Journal of Testing and Evaluation","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135343031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Applying the Integrated Digital Image Correlation Method to Detect Stress Measurements in Precision Drilling","authors":"Ming-Hsiang Shih, Shih-Heng Tung, Wen-Pei Sung","doi":"10.1520/jte20230298","DOIUrl":"https://doi.org/10.1520/jte20230298","url":null,"abstract":"","PeriodicalId":17109,"journal":{"name":"Journal of Testing and Evaluation","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135477163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The softening point is one of the important indexes used to evaluate the high-temperature performance of asphalt. However, some modified asphalt softening points show irregular changes before and after aging, and the correlation with other high-temperature indexes is not high, which has been a concern for researchers. To this end, this work takes styrene-butadiene-styrene–modified asphalt as the research object and long- and short-term aging as the condition, through the improvement of softening point test and combined with the temperature-sensitive correlation, differential scanning calorimetry, and dynamic shear rheology tests, to explore the significance of improving the softening point test–related indicators to provide new ideas for the asphalt performance evaluation system.
{"title":"Research on Temperature Stability of Asphalt Based on Improved Softening Point Test","authors":"Zhihua Xue, Lan Wang, Chao Li, Le Zhang","doi":"10.1520/jte20220544","DOIUrl":"https://doi.org/10.1520/jte20220544","url":null,"abstract":"The softening point is one of the important indexes used to evaluate the high-temperature performance of asphalt. However, some modified asphalt softening points show irregular changes before and after aging, and the correlation with other high-temperature indexes is not high, which has been a concern for researchers. To this end, this work takes styrene-butadiene-styrene–modified asphalt as the research object and long- and short-term aging as the condition, through the improvement of softening point test and combined with the temperature-sensitive correlation, differential scanning calorimetry, and dynamic shear rheology tests, to explore the significance of improving the softening point test–related indicators to provide new ideas for the asphalt performance evaluation system.","PeriodicalId":17109,"journal":{"name":"Journal of Testing and Evaluation","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135768783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper discusses the effect of magnetic fields on the tensile properties of high-strength carbon-manganese steel sheets in uniaxial tension. An electromagnetic tool was designed and fabricated such that it produced a constant magnetic field of 0.35 T in the gauge length of a tensile specimen during testing. Experimental measurements of magnetic flux density distribution confirm the model, which is further validated with theoretical analysis. The tensile properties are examined with and without the effect of a magnetic field. A significant improvement is observed in tensile strength and normal anisotropy of the material because of the effect of the magnetic field. Samples were taken from the middle of specimens that were tested with 20 % plastic strain for microstructural investigations using the electron backscattered diffraction technique, and in all cases experiments were performed with and without the magnetic field. Geometrically necessary dislocations maps exhibiting the measure of dislocation density during plastic deformation show lesser accumulation of dislocations at the grain boundaries with the effect of the magnetic field, which indicates hindrance to the movement of dislocations as a result of the severe interaction of dislocations with the magnetic domains. The results also show an increase in grain size and the development of a weak texture for the tested specimens with the applied magnetic field as compared with the specimens tested without the magnetic field. The microstructural findings correlate with changes in the tensile properties.
{"title":"Effect of Magnetic Field on Deformation Behavior of a Steel Sheet in Uniaxial Tension","authors":"Ravi Datt Yadav, Vijay Gautam","doi":"10.1520/jte20230284","DOIUrl":"https://doi.org/10.1520/jte20230284","url":null,"abstract":"This paper discusses the effect of magnetic fields on the tensile properties of high-strength carbon-manganese steel sheets in uniaxial tension. An electromagnetic tool was designed and fabricated such that it produced a constant magnetic field of 0.35 T in the gauge length of a tensile specimen during testing. Experimental measurements of magnetic flux density distribution confirm the model, which is further validated with theoretical analysis. The tensile properties are examined with and without the effect of a magnetic field. A significant improvement is observed in tensile strength and normal anisotropy of the material because of the effect of the magnetic field. Samples were taken from the middle of specimens that were tested with 20 % plastic strain for microstructural investigations using the electron backscattered diffraction technique, and in all cases experiments were performed with and without the magnetic field. Geometrically necessary dislocations maps exhibiting the measure of dislocation density during plastic deformation show lesser accumulation of dislocations at the grain boundaries with the effect of the magnetic field, which indicates hindrance to the movement of dislocations as a result of the severe interaction of dislocations with the magnetic domains. The results also show an increase in grain size and the development of a weak texture for the tested specimens with the applied magnetic field as compared with the specimens tested without the magnetic field. The microstructural findings correlate with changes in the tensile properties.","PeriodicalId":17109,"journal":{"name":"Journal of Testing and Evaluation","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136011122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In order to systematically assess the influence of the internal structure on the outgassing property, alumina ceramics with different porosity were first prepared by four sintering processes, and then their measurements of the outgassing rate and desorption gas components were performed using the throughput method. Experimental results show that when the alumina sample is exposed to vacuum for just a few hours, surface outgassing dominants and the main outgassing component is water vapor. After sufficiently long vacuum extraction, the gas inside the alumina ceramic is gradually released. In this test, the gas released from the internal structure plays a dominant role after 48 h pumping of 600 L/s. Combined with the microstructure analysis, it is further concluded that the denser the alumina structure is, the lower the vacuum outgassing rate is and the lower the partial pressure of the individual gas components is. It can also be observed that the internal structure still has some influence on the outgassing characteristics of the material, although to a slightly lower degree than the surface properties compared to previous studies.
{"title":"Research on the Effect of Density on the Outgassing Characteristics of Ceramics","authors":"Yan Luo, Kuibo Wang, Xiaobin Wu","doi":"10.1520/jte20230335","DOIUrl":"https://doi.org/10.1520/jte20230335","url":null,"abstract":"In order to systematically assess the influence of the internal structure on the outgassing property, alumina ceramics with different porosity were first prepared by four sintering processes, and then their measurements of the outgassing rate and desorption gas components were performed using the throughput method. Experimental results show that when the alumina sample is exposed to vacuum for just a few hours, surface outgassing dominants and the main outgassing component is water vapor. After sufficiently long vacuum extraction, the gas inside the alumina ceramic is gradually released. In this test, the gas released from the internal structure plays a dominant role after 48 h pumping of 600 L/s. Combined with the microstructure analysis, it is further concluded that the denser the alumina structure is, the lower the vacuum outgassing rate is and the lower the partial pressure of the individual gas components is. It can also be observed that the internal structure still has some influence on the outgassing characteristics of the material, although to a slightly lower degree than the surface properties compared to previous studies.","PeriodicalId":17109,"journal":{"name":"Journal of Testing and Evaluation","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136010959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dongyu Xu, Huaicheng Chen, Mei Cao, Yuli Cui, Junsheng Bai, Shoude Wang
Freezing and thawing behavior are among the most important factors when determining the durability of engineering structures in cold regions. A kind of acoustic emission (AE) sensor was tailored to evaluate the freezing-thawing characteristics of concrete. The AE test results show that, under uniaxial compression loading, the concrete not experiencing freezing-thawing cycles has a little ring down count (RDC) at the initial loading stage, which then increases because of the appearance of amounts of damage cracks at the later loading period. The AE characteristics of the concrete after freezing-thawing under compressive loading were analyzed. The results show that RDC in the first 100 s of loading is little, which increases suddenly with loading. The RDC and accumulative ring down count of the concrete with different freezing-thawing cycles show the decreasing trend, and the maxima of the accumulative energy decreases with increasing the freezing-thawing cycles.
{"title":"Acoustic Emission Characteristics of Frost-Damaged Concrete under Compressive Loading","authors":"Dongyu Xu, Huaicheng Chen, Mei Cao, Yuli Cui, Junsheng Bai, Shoude Wang","doi":"10.1520/jte20230187","DOIUrl":"https://doi.org/10.1520/jte20230187","url":null,"abstract":"Freezing and thawing behavior are among the most important factors when determining the durability of engineering structures in cold regions. A kind of acoustic emission (AE) sensor was tailored to evaluate the freezing-thawing characteristics of concrete. The AE test results show that, under uniaxial compression loading, the concrete not experiencing freezing-thawing cycles has a little ring down count (RDC) at the initial loading stage, which then increases because of the appearance of amounts of damage cracks at the later loading period. The AE characteristics of the concrete after freezing-thawing under compressive loading were analyzed. The results show that RDC in the first 100 s of loading is little, which increases suddenly with loading. The RDC and accumulative ring down count of the concrete with different freezing-thawing cycles show the decreasing trend, and the maxima of the accumulative energy decreases with increasing the freezing-thawing cycles.","PeriodicalId":17109,"journal":{"name":"Journal of Testing and Evaluation","volume":"150 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136263712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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