In the past 20 years,recycled aggregate concrete(RAC),as a type of low-carbon concrete,has become a worldwide focus of research.However,the design methodology for RAC structural components remains a challenge.Conseque...In the past 20 years,recycled aggregate concrete(RAC),as a type of low-carbon concrete,has become a worldwide focus of research.However,the design methodology for RAC structural components remains a challenge.Consequently,demands for a unified design of natural aggregate concrete(NAC)and RAC components have been presented.Accordingly,this study analyses the necessity of a unified design theory and provides an in-depth demonstration of the strength determination,compressive constitutive relationship,and design method of concrete components.The coefficient of variation of RAC strength is found to be generally higher than that of NAC strength.The compressive and tensile strengths of RAC can be defined and determined using the same method as that used for NAC.The uniaxial compressive constitutive relationship between NAC and RAC has a unified mathematical expression.However,the elastic modulus of RAC decreases,and its brittleness exhibits an increasing trend compared with that of NAC.Finally,to unify the design formulae of RAC and NAC components for bearing capacity,modification factors for RAC components are proposed considering safety and reliability.Additionally,the feasibility of the proposed unified time-dependent design theory is demonstrated in terms of conceptual design and structural measures considering the effects of strength degradation and reinforcement corrosion.It is believed that this study enriches and develops the basic theory of concrete structures.展开更多
Marx and Engles believed that man and nature develop harmoniously, when the activities of man constitute the content of nature, which is changed constantly because of the activities of man. Marx and Engles also pointe...Marx and Engles believed that man and nature develop harmoniously, when the activities of man constitute the content of nature, which is changed constantly because of the activities of man. Marx and Engles also pointed out the duality of the conquest, change and influence exerted on nature by man. On one hand, it can improve people’s living conditions and make people free from the enslavement of the nature. On the other hand, it may also lead to excessively snatching and wrecking nature, then make the deterioration of the environment and ecology out of balance. They also, from the technical angle of ecology, put forward the concrete measures to realize the harmonious symbiosis of man and nature in the development of economy. They also believed that only when socialism or communism is realized, can the conciliation of mankind and nature be realized finally. Marx and Engle’s theory of harmonious symbiosis of man and nature is of great theoretical directive significance for us to insist on the scientific development view.展开更多
The harmony between man and nature is the base for the harmonious society. It is determined by the eco-ruleand eco-economic rule. Human being should not violate the eco-rule. However, human being can make eco-systemsu...The harmony between man and nature is the base for the harmonious society. It is determined by the eco-ruleand eco-economic rule. Human being should not violate the eco-rule. However, human being can make eco-systemsupply suit economic growth and its speed through systematical innovation and restriction of human economic activityand choice. Through technological innovation, efficiency satisfaction of unit resource can be increased; structure andfunction of eco-system can be perfected; supply capability of eco-system can be improved. To build the harmonioussociety, human should consider the reasonable distribution of limited resources from two sides. The first one is that theutilization of two functions of resource supply and pollution purification to nature should not exceed its special supplycapability formed under its special structure and function states, i.e. harmony between man and nature. The second sideis human being should think over the reasonable and effective distribution of limited resources in economic society, i.e.harmony between human beings and society. The reasonable economic activity of human being is the key to the harmo-nious development of man and nature.展开更多
With the advancement of ecological conservation in China,the concept of green development has gained extensive acceptance and recognition.Exploring green development from the perspectives of environmental protection a...With the advancement of ecological conservation in China,the concept of green development has gained extensive acceptance and recognition.Exploring green development from the perspectives of environmental protection and sociology holds great theoretical value and practical significance in studying the issues related to green development.Firstly,this paper examines green development in light of the objective needs of the economic and social transformation in the international community and China,and deconstructed its underlying social logic.Secondly,it further investigates the social factors that restrict green development,encompassing social structures,social concepts,social systems,and social behaviors.Finally,within the framework of the“green”discipline system in environmental sociology,this paper proposes specific measures such as restructuring social systems and transforming production modes,lifestyles,and consumption patterns to promote green development.展开更多
基金the financial support from the Distinguished Young Scholars of China by the National Natural Science Foundation of China(51325802)the National Natural Science Foundation of China(51178340,52078358,and 52008304)。
文摘In the past 20 years,recycled aggregate concrete(RAC),as a type of low-carbon concrete,has become a worldwide focus of research.However,the design methodology for RAC structural components remains a challenge.Consequently,demands for a unified design of natural aggregate concrete(NAC)and RAC components have been presented.Accordingly,this study analyses the necessity of a unified design theory and provides an in-depth demonstration of the strength determination,compressive constitutive relationship,and design method of concrete components.The coefficient of variation of RAC strength is found to be generally higher than that of NAC strength.The compressive and tensile strengths of RAC can be defined and determined using the same method as that used for NAC.The uniaxial compressive constitutive relationship between NAC and RAC has a unified mathematical expression.However,the elastic modulus of RAC decreases,and its brittleness exhibits an increasing trend compared with that of NAC.Finally,to unify the design formulae of RAC and NAC components for bearing capacity,modification factors for RAC components are proposed considering safety and reliability.Additionally,the feasibility of the proposed unified time-dependent design theory is demonstrated in terms of conceptual design and structural measures considering the effects of strength degradation and reinforcement corrosion.It is believed that this study enriches and develops the basic theory of concrete structures.
文摘Marx and Engles believed that man and nature develop harmoniously, when the activities of man constitute the content of nature, which is changed constantly because of the activities of man. Marx and Engles also pointed out the duality of the conquest, change and influence exerted on nature by man. On one hand, it can improve people’s living conditions and make people free from the enslavement of the nature. On the other hand, it may also lead to excessively snatching and wrecking nature, then make the deterioration of the environment and ecology out of balance. They also, from the technical angle of ecology, put forward the concrete measures to realize the harmonious symbiosis of man and nature in the development of economy. They also believed that only when socialism or communism is realized, can the conciliation of mankind and nature be realized finally. Marx and Engle’s theory of harmonious symbiosis of man and nature is of great theoretical directive significance for us to insist on the scientific development view.
文摘The harmony between man and nature is the base for the harmonious society. It is determined by the eco-ruleand eco-economic rule. Human being should not violate the eco-rule. However, human being can make eco-systemsupply suit economic growth and its speed through systematical innovation and restriction of human economic activityand choice. Through technological innovation, efficiency satisfaction of unit resource can be increased; structure andfunction of eco-system can be perfected; supply capability of eco-system can be improved. To build the harmonioussociety, human should consider the reasonable distribution of limited resources from two sides. The first one is that theutilization of two functions of resource supply and pollution purification to nature should not exceed its special supplycapability formed under its special structure and function states, i.e. harmony between man and nature. The second sideis human being should think over the reasonable and effective distribution of limited resources in economic society, i.e.harmony between human beings and society. The reasonable economic activity of human being is the key to the harmo-nious development of man and nature.
文摘With the advancement of ecological conservation in China,the concept of green development has gained extensive acceptance and recognition.Exploring green development from the perspectives of environmental protection and sociology holds great theoretical value and practical significance in studying the issues related to green development.Firstly,this paper examines green development in light of the objective needs of the economic and social transformation in the international community and China,and deconstructed its underlying social logic.Secondly,it further investigates the social factors that restrict green development,encompassing social structures,social concepts,social systems,and social behaviors.Finally,within the framework of the“green”discipline system in environmental sociology,this paper proposes specific measures such as restructuring social systems and transforming production modes,lifestyles,and consumption patterns to promote green development.