The influence of air-cooled blast furnace slag aggregates as replacement of natural aggregates on the water absorption of concrete and mortar was studied, and the mechanism was analyzed. The interface between aggregat...The influence of air-cooled blast furnace slag aggregates as replacement of natural aggregates on the water absorption of concrete and mortar was studied, and the mechanism was analyzed. The interface between aggregate and matrix in concrete was analyzed by using a micro-hardness tester, a laser confocal microscope and a scanning electron microscope with backscattered electron image mode. The pore structure of mortar matrixes under different curing conditions was investigated by mercury intrusion porosimetry. The results showed that when natural aggregates were replaced with air-cooled blast furnace slag aggregates in mortar or concrete, the content of the capillary pore in the mortar matrix was reduced and the interfacial structure between aggregate and matrix was improved, resulting in the lower water absorption of mortar or concrete. Compared to the concrete made with crushed limestone and natural river sand, the initial absorption coefficient, the secondary absorption coefficient and the water absorption capacity through the surface for 7 d of the concrete made from crushed air-cooled blast furnace slag and air-cooled blast furnace slag sand were reduced by 48.9%, 52.8%, and 46.5%, respectively.展开更多
We proposed a novel efficient operation scheme for a thermal power plant’s air-cooling system based on peak shaving, in order to cope with high ambient temperature in summer. We introduced an absorptiongeneration equ...We proposed a novel efficient operation scheme for a thermal power plant’s air-cooling system based on peak shaving, in order to cope with high ambient temperature in summer. We introduced an absorptiongeneration equipment with water/lithium working pairs into the air cooled condenser(ACC) to reconstruct the traditional thermal power plant, and established a dynamic thermodynamic model adopting Ebsilon code. We studied the thermodynamic performance variation of the reconstructed thermal power plant throughout a 24-hour cycle and found that the fluctuation ratio of the turbine back pressure decreased to 6% from 78%, which is beneficial for the stable and safe operation of the electric power system. The thermal performance improvement benefited from the exploitation of the heat transfer potential of ACC, which realized via cold duty schedule throughout the day, under different ambient temperature conditions. In this system, the generated power was higher at relatively high ambient temperature than that at relatively low ambient temperature, which solved the electricity demand-supply imbalance problem under high ambient temperature. Finally, the same optimization effects for power thermal plants with an indirect air-cooling system were obtained using the same operation scheme.展开更多
In the construction of Three Gorges Project, the total amount of concrete is about 28 Mm\+3 , and the total amount of metal works and reinforcement is approximately 0.72 Mt . The TGP is constructed in 3 stages . The p...In the construction of Three Gorges Project, the total amount of concrete is about 28 Mm\+3 , and the total amount of metal works and reinforcement is approximately 0.72 Mt . The TGP is constructed in 3 stages . The preparation period together with the first stage is 5 years , the second stage and third stage are both 6 years .In the second stage construction of 6 years (1998～2003) , there are 18.46 Mm\+3 of concrete to be placed and 0.192 Mt of metal works and embedded parts for mechanical and electric equipment to be installed . In 1999, a world record of annual concrete placement of 4.585 Mm\+3 was set . In 2000, it is planned to place 5.4 Mm\+3 of concrete and to install 38 000 t of metal works . Construction equipments and layout of construction site , concrete production and its temperature control, metal works, mechanical and electric equipments in the second stage construction are presented.展开更多
基金Funded by the National Natural Science Foundation of China(Nos.51778003 and 51308004)the Project of Anhui Provincial Education Department for Sending Visiting Scholars to Research Abroad(No.gxfx ZD2016134)+1 种基金the Anhui Province Higher Education Revitalization Program Talent Project([2014]No.11)the National Key Research and Development Plan(No.2017YFB0310001)
文摘The influence of air-cooled blast furnace slag aggregates as replacement of natural aggregates on the water absorption of concrete and mortar was studied, and the mechanism was analyzed. The interface between aggregate and matrix in concrete was analyzed by using a micro-hardness tester, a laser confocal microscope and a scanning electron microscope with backscattered electron image mode. The pore structure of mortar matrixes under different curing conditions was investigated by mercury intrusion porosimetry. The results showed that when natural aggregates were replaced with air-cooled blast furnace slag aggregates in mortar or concrete, the content of the capillary pore in the mortar matrix was reduced and the interfacial structure between aggregate and matrix was improved, resulting in the lower water absorption of mortar or concrete. Compared to the concrete made with crushed limestone and natural river sand, the initial absorption coefficient, the secondary absorption coefficient and the water absorption capacity through the surface for 7 d of the concrete made from crushed air-cooled blast furnace slag and air-cooled blast furnace slag sand were reduced by 48.9%, 52.8%, and 46.5%, respectively.
基金Financial support from the National Natural Science Foundation of China(NSFC)project(Grant No.51806217)International Cooperation Project(Grant No.2016YFE0118100)Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA 21010201)is gratefully acknowledged.
文摘We proposed a novel efficient operation scheme for a thermal power plant’s air-cooling system based on peak shaving, in order to cope with high ambient temperature in summer. We introduced an absorptiongeneration equipment with water/lithium working pairs into the air cooled condenser(ACC) to reconstruct the traditional thermal power plant, and established a dynamic thermodynamic model adopting Ebsilon code. We studied the thermodynamic performance variation of the reconstructed thermal power plant throughout a 24-hour cycle and found that the fluctuation ratio of the turbine back pressure decreased to 6% from 78%, which is beneficial for the stable and safe operation of the electric power system. The thermal performance improvement benefited from the exploitation of the heat transfer potential of ACC, which realized via cold duty schedule throughout the day, under different ambient temperature conditions. In this system, the generated power was higher at relatively high ambient temperature than that at relatively low ambient temperature, which solved the electricity demand-supply imbalance problem under high ambient temperature. Finally, the same optimization effects for power thermal plants with an indirect air-cooling system were obtained using the same operation scheme.
文摘In the construction of Three Gorges Project, the total amount of concrete is about 28 Mm\+3 , and the total amount of metal works and reinforcement is approximately 0.72 Mt . The TGP is constructed in 3 stages . The preparation period together with the first stage is 5 years , the second stage and third stage are both 6 years .In the second stage construction of 6 years (1998～2003) , there are 18.46 Mm\+3 of concrete to be placed and 0.192 Mt of metal works and embedded parts for mechanical and electric equipment to be installed . In 1999, a world record of annual concrete placement of 4.585 Mm\+3 was set . In 2000, it is planned to place 5.4 Mm\+3 of concrete and to install 38 000 t of metal works . Construction equipments and layout of construction site , concrete production and its temperature control, metal works, mechanical and electric equipments in the second stage construction are presented.
