Traditional cement concrete has the disadvantages of low tensile strength,poor toughness,and rapid development of cracks while cracking,which causes a significantly negative influence on the safety and durability of c...Traditional cement concrete has the disadvantages of low tensile strength,poor toughness,and rapid development of cracks while cracking,which causes a significantly negative influence on the safety and durability of concrete road pavement.This paper presents a state-of-the-art review of toughness improvement mechanisms and evaluation methods of cement concrete for road pavement.The review indicates that(i)The performance of concrete material depends on its material composition and internal structure.Aggregate size,cement properties and admixtures are the main factors of concrete toughness.(ii)The incorporation of rubber or fiber in pavement concrete improves the toughness of concrete materials.However,these additions must be maintained within a reasonable range.The amount of rubber and fiber are encouraged not more than 30%of the volume of fine aggregate and 2%of the volume of concrete,respectively.(iii)The toughness of pavement concrete material includes the toughness regarding bending,impact and fracture.The toughness of cement concrete for highway and municipal pavement is generally evaluated by bending and fracture toughness,while the toughness of airfield pavement concrete is more focused on impact toughness.(iv)The toughening measures of cement concrete for road pavement are mainly mixed with rubber or fiber,while these two materials have their defects,and the application of hightoughness cement concrete in the actual road still faces many challenges.For example,the synergistic effect of rubber and fiber,the development and application of new flexible admixtures,and the formulation of the toughness index of pavement cement concrete materials need further research.展开更多
This paper studies the safety management of oil and gas long-distance pipeline. The significance of safety management of oil and gas long-distance pipeline is analyzed. From the pipeline facilities, surface vegetation...This paper studies the safety management of oil and gas long-distance pipeline. The significance of safety management of oil and gas long-distance pipeline is analyzed. From the pipeline facilities, surface vegetation, natural disasters, human activities, illegal occupation and other aspects, the paper analyzes the safety management problems of oil and gas long-distance pipeline. From the perspectives of anti-corrosion materials and technologies, leakage detection, risk assessment and pipeline integrity management, the paper lists the safety management technologies of long-distance oil and gas pipelines and analyzes their development. This paper lists the safety management strategies of long distance oil and gas pipelines from the perspectives of quality control of pipeline construction, prevention of natural disasters, security work, supervision of illegal occupation of pressure, application of detection means and improvement of liaison mechanism.展开更多
With the development level of science and technology, electric power equipment is more widely used in the field of railway. Railway power equipment in the long use process may have some fault problems affect the norma...With the development level of science and technology, electric power equipment is more widely used in the field of railway. Railway power equipment in the long use process may have some fault problems affect the normal operation, so the railway unit should improve the attention to state maintenance technology, create a complete railway equipment state maintenance system, so that state maintenance technology can give full play to the application value in the railway power equipment management. This paper firstly analyzes the necessity of state maintenance of railway power equipment, and then discusses the measures to strengthen the maintenance management and maintenance of railway power equipment in order to have certain reference value for relevant research.展开更多
With the rapid development of submarine oil and gas,the security issues of submarine oil and gas pipeline become increasingly prominent,and regular inspection of submarine pipeline is particularly important.Therefore,...With the rapid development of submarine oil and gas,the security issues of submarine oil and gas pipeline become increasingly prominent,and regular inspection of submarine pipeline is particularly important.Therefore,a submarine pipeline inspection robot system based on CT technology to solve the problems such as low traditional manual inspection efficiency,high labor cost,low security and backward inspection methods.Based on the platform of ROV robot,carrying CT scanner as an external detection device,the system is used for non-invasive inspection of submarine pipeline,which is safe and harmless,with good economy,high mobility,and strong environmental adaptability.Compared with traditional technology,CT scanner’s external inspection technology used in the system avoids the damage to the external protective layer of the pipeline in the measurement of pipeline wall thickness.Meantime,it can provide the tomography of the pipe wall and the composition of the sediment material on the inside wall,which fills the gap in this technical field in China.According to the test,the robot has the characteristics of stable adsorption,flexible movement,and clear pipeline CT scanning image,and can realize the intelligent inspection of submarine pipeline.展开更多
基金This research is financially supported by the Research Program of China Railway Siyuan Survey and Design Group Co.,Ltd.(Grant number 2021K066).
文摘Traditional cement concrete has the disadvantages of low tensile strength,poor toughness,and rapid development of cracks while cracking,which causes a significantly negative influence on the safety and durability of concrete road pavement.This paper presents a state-of-the-art review of toughness improvement mechanisms and evaluation methods of cement concrete for road pavement.The review indicates that(i)The performance of concrete material depends on its material composition and internal structure.Aggregate size,cement properties and admixtures are the main factors of concrete toughness.(ii)The incorporation of rubber or fiber in pavement concrete improves the toughness of concrete materials.However,these additions must be maintained within a reasonable range.The amount of rubber and fiber are encouraged not more than 30%of the volume of fine aggregate and 2%of the volume of concrete,respectively.(iii)The toughness of pavement concrete material includes the toughness regarding bending,impact and fracture.The toughness of cement concrete for highway and municipal pavement is generally evaluated by bending and fracture toughness,while the toughness of airfield pavement concrete is more focused on impact toughness.(iv)The toughening measures of cement concrete for road pavement are mainly mixed with rubber or fiber,while these two materials have their defects,and the application of hightoughness cement concrete in the actual road still faces many challenges.For example,the synergistic effect of rubber and fiber,the development and application of new flexible admixtures,and the formulation of the toughness index of pavement cement concrete materials need further research.
文摘This paper studies the safety management of oil and gas long-distance pipeline. The significance of safety management of oil and gas long-distance pipeline is analyzed. From the pipeline facilities, surface vegetation, natural disasters, human activities, illegal occupation and other aspects, the paper analyzes the safety management problems of oil and gas long-distance pipeline. From the perspectives of anti-corrosion materials and technologies, leakage detection, risk assessment and pipeline integrity management, the paper lists the safety management technologies of long-distance oil and gas pipelines and analyzes their development. This paper lists the safety management strategies of long distance oil and gas pipelines from the perspectives of quality control of pipeline construction, prevention of natural disasters, security work, supervision of illegal occupation of pressure, application of detection means and improvement of liaison mechanism.
文摘With the development level of science and technology, electric power equipment is more widely used in the field of railway. Railway power equipment in the long use process may have some fault problems affect the normal operation, so the railway unit should improve the attention to state maintenance technology, create a complete railway equipment state maintenance system, so that state maintenance technology can give full play to the application value in the railway power equipment management. This paper firstly analyzes the necessity of state maintenance of railway power equipment, and then discusses the measures to strengthen the maintenance management and maintenance of railway power equipment in order to have certain reference value for relevant research.
文摘With the rapid development of submarine oil and gas,the security issues of submarine oil and gas pipeline become increasingly prominent,and regular inspection of submarine pipeline is particularly important.Therefore,a submarine pipeline inspection robot system based on CT technology to solve the problems such as low traditional manual inspection efficiency,high labor cost,low security and backward inspection methods.Based on the platform of ROV robot,carrying CT scanner as an external detection device,the system is used for non-invasive inspection of submarine pipeline,which is safe and harmless,with good economy,high mobility,and strong environmental adaptability.Compared with traditional technology,CT scanner’s external inspection technology used in the system avoids the damage to the external protective layer of the pipeline in the measurement of pipeline wall thickness.Meantime,it can provide the tomography of the pipe wall and the composition of the sediment material on the inside wall,which fills the gap in this technical field in China.According to the test,the robot has the characteristics of stable adsorption,flexible movement,and clear pipeline CT scanning image,and can realize the intelligent inspection of submarine pipeline.
