To relieve the increasing traffic load, many early built highways need to be widened or reconstructed. The rapid performance detection to existing subgrades is important to their reasonable evaluation and maximized ut...To relieve the increasing traffic load, many early built highways need to be widened or reconstructed. The rapid performance detection to existing subgrades is important to their reasonable evaluation and maximized utilization. Based on five kinds of soils taken from an existing highway in southern China, three commonly detecting methods were used to determine their moisture contents, compaction degrees and resilient moduli. The results showed that the measured moisture contents were greater than the design value, and the compaction degrees decreased sharply compared to the original ones. The moisture and heat exchange produced a decrease in the resilient modulus of plate loading test(PLT) from the standard 60 MPa down to 40 MPa. Afterwards, the portable falling weight deflectometer(PFWD) and dynamic cone penetrometer(DCP) were used to evaluate the subgrade performances. The measured PFWD moduli and the DCP penetration rates were correlated with the resilient moduli of PLT, deflections of the Beckman beam test, compaction degrees and moisture contents. The correlation analysis indicates that both of two methods are suitable in rapid detecting subgrade performances, but PFWD method is more recommended for it has higher accuracy and efficiency.展开更多
In order to investigate the existing form and action mechanism of minor scandium （Sc） and zirconium （Zr） in AI-Cu-Mg alloy, microstructures of Al-4Cu-1Mg-Sc-Zr alloy under different conditions, including states of...In order to investigate the existing form and action mechanism of minor scandium （Sc） and zirconium （Zr） in AI-Cu-Mg alloy, microstructures of Al-4Cu-1Mg-Sc-Zr alloy under different conditions, including states of as-cast, homogenized, hot-rolled, as-solution and natural aged, were observed by scanning electron microscopy （SEM）, X-ray diffractometry （XRD） and transmission electron microscopy （TEM）. It is revealed that Sc and Zr are completely dissolved into the supersaturated solid solution in as-cast ingot, but grain refinement is not observed. Coffee-bean-like AI3（Sc, Zr） particles deposit during homogenization of ingot induce an increase in hardness. Al3（Sc, Zr） particles are slightly coarsened in as-solution samples, but they still maintain coherent to matrix, which indicates a high thermal stability of these particles. Good coherency ofAl3（Sc, Zr） particles makes some benefits for inhibiting recrystallization and reserving work-hardening.展开更多
The comprehensive benefit evaluation of the existing building energy efficient renovation project cannot be separated from the scientific and effective evaluation mechanism.Based on the value-added life perspective,th...The comprehensive benefit evaluation of the existing building energy efficient renovation project cannot be separated from the scientific and effective evaluation mechanism.Based on the value-added life perspective,this paper analyzes the implementation subject,standard,system and principle of the comprehensive benefit evaluation of the existing building energy efficient renovation project.It plans the process of comprehensive benefit evaluation,and builds a scientific and reasonable operation platform of evaluation system,with a view to promoting the effective implementation of the comprehensive benefit evaluation of existing building energy-saving retrofits.展开更多
It is the key to promote the development of energy-saving renovation market of existing buildings to share the social responsibility of the subject of energy-saving renovation of existing buildings.This paper analyzes...It is the key to promote the development of energy-saving renovation market of existing buildings to share the social responsibility of the subject of energy-saving renovation of existing buildings.This paper analyzes the principle and implementation conditions of social responsibility sharing of existing building energy-saving renovation subject,discusses the mode selection and contract design of social responsibility sharing of existing building energy-saving renovation subject,analyzes the implementation mechanism of social responsibility sharing of existing building energy-saving renovation subject from the perspectives of information platform architecture,shared process design and shared system construction.And this paper puts forward the implementation strategy of sharing the social responsibility of the subject of the existing building energy-saving renovation from the aspects of stabilizing the subject’s cooperative relationship,creating a good responsibility environment and improving the responsibility performance laws and regulations.展开更多
基金Project(2017YFC0805307) supported by the National Key Research and Development Program of ChinaProjects(51878078, 51927814, 51911530215) supported by the National Natural Science Foundation of China+4 种基金Project(2018-025) supported by the Training Program for High-level Technical Personnel in Transportation Industry, ChinaProject (2018JJ1026) supported by the Excellent Youth Foundation of Natural Science Foundation of Hunan Province, ChinaProject(17A008) supported by the Key Project of Education Department of Hunan Province, ChinaProjects(kfj150103, kfj170104) supported by the Open Research Fund of State Engineering Laboratory of Highway Maintenance Technology, Changsha University of Science & Technology, ChinaProject(CX20190644) supported by the Postgraduate Scientific Research Innovation Project of Hunan Province, China。
文摘To relieve the increasing traffic load, many early built highways need to be widened or reconstructed. The rapid performance detection to existing subgrades is important to their reasonable evaluation and maximized utilization. Based on five kinds of soils taken from an existing highway in southern China, three commonly detecting methods were used to determine their moisture contents, compaction degrees and resilient moduli. The results showed that the measured moisture contents were greater than the design value, and the compaction degrees decreased sharply compared to the original ones. The moisture and heat exchange produced a decrease in the resilient modulus of plate loading test(PLT) from the standard 60 MPa down to 40 MPa. Afterwards, the portable falling weight deflectometer(PFWD) and dynamic cone penetrometer(DCP) were used to evaluate the subgrade performances. The measured PFWD moduli and the DCP penetration rates were correlated with the resilient moduli of PLT, deflections of the Beckman beam test, compaction degrees and moisture contents. The correlation analysis indicates that both of two methods are suitable in rapid detecting subgrade performances, but PFWD method is more recommended for it has higher accuracy and efficiency.
基金Project(2005DFA50550) supported by International Science and Technology Cooperation Program of ChinaProject(2005CB623705) supported by the National Basic Research Program of China
文摘In order to investigate the existing form and action mechanism of minor scandium （Sc） and zirconium （Zr） in AI-Cu-Mg alloy, microstructures of Al-4Cu-1Mg-Sc-Zr alloy under different conditions, including states of as-cast, homogenized, hot-rolled, as-solution and natural aged, were observed by scanning electron microscopy （SEM）, X-ray diffractometry （XRD） and transmission electron microscopy （TEM）. It is revealed that Sc and Zr are completely dissolved into the supersaturated solid solution in as-cast ingot, but grain refinement is not observed. Coffee-bean-like AI3（Sc, Zr） particles deposit during homogenization of ingot induce an increase in hardness. Al3（Sc, Zr） particles are slightly coarsened in as-solution samples, but they still maintain coherent to matrix, which indicates a high thermal stability of these particles. Good coherency ofAl3（Sc, Zr） particles makes some benefits for inhibiting recrystallization and reserving work-hardening.
文摘The comprehensive benefit evaluation of the existing building energy efficient renovation project cannot be separated from the scientific and effective evaluation mechanism.Based on the value-added life perspective,this paper analyzes the implementation subject,standard,system and principle of the comprehensive benefit evaluation of the existing building energy efficient renovation project.It plans the process of comprehensive benefit evaluation,and builds a scientific and reasonable operation platform of evaluation system,with a view to promoting the effective implementation of the comprehensive benefit evaluation of existing building energy-saving retrofits.
基金supported by the National Natural Science Foundation of China(Grant No.71573188)Late-stage Subsidy Project of Humanities and Social Sciences of the Education Department of China(Grant No.16JHQ031)+1 种基金Tianjin Social Science Planning later support project(Grant No.TJGLHQ1403)Tianjin University Innovation Team(Grant No.TD13-5006)
文摘It is the key to promote the development of energy-saving renovation market of existing buildings to share the social responsibility of the subject of energy-saving renovation of existing buildings.This paper analyzes the principle and implementation conditions of social responsibility sharing of existing building energy-saving renovation subject,discusses the mode selection and contract design of social responsibility sharing of existing building energy-saving renovation subject,analyzes the implementation mechanism of social responsibility sharing of existing building energy-saving renovation subject from the perspectives of information platform architecture,shared process design and shared system construction.And this paper puts forward the implementation strategy of sharing the social responsibility of the subject of the existing building energy-saving renovation from the aspects of stabilizing the subject’s cooperative relationship,creating a good responsibility environment and improving the responsibility performance laws and regulations.
