The permeability of lightweight aggregate concrete was studied. Some efforts were taken to increase the resistance of lightweight aggregate concrete (LC) to water penetration by using the mineral admixtures of fly ash...The permeability of lightweight aggregate concrete was studied. Some efforts were taken to increase the resistance of lightweight aggregate concrete (LC) to water penetration by using the mineral admixtures of fly ash, granulated blast furnace slag or silica fume. Accelerated chloride penetrability test and liquid atmosphere press method were used to study the anti-permeability of lightweight aggregate concrete. The experimental results show that fly ash, granulated blast furnace slag and silica fume can decrease the permeability of lightweight aggregate concrete, but the effect of granulated blast furnace slag is poor. According to the SEM and pore structure analyzing results,an interface self-reinforcing effect model was presented and the reinforced mechanism of mineral mixture on LC was discussed according to the model described by authors.展开更多
The self-reinforced Si_3N_4 ceramics which contain Y_2O_3 and La_2O_3 additives have been prepared by hot-pressing. Under the optimum processing conditions, this material has the flexural strength of 960～1050MPa and ...The self-reinforced Si_3N_4 ceramics which contain Y_2O_3 and La_2O_3 additives have been prepared by hot-pressing. Under the optimum processing conditions, this material has the flexural strength of 960～1050MPa and the fracture toughness of 11.17～12.74MPa·m^(1/2) at room-temperature, and 720～780MPa and 22～24MPa·m^(1/2) at 1350℃. The effects of heat ing rate, sintering temperature, and holding time on the microstructures and mechanical properties are investigated. The experimental results show that an appropriate β-Si_3N_4 grain size and homogeneous microstructure can be obtained under the conditions of a heating rate of 10℃/min, sintering temperature of 1800℃, and holding time of 1h, which are advantageous to enhancing the mechanical properties. Crack deflection in large rodlike β-Si_3N_4 grains is a principle source of toughening.展开更多
文摘The permeability of lightweight aggregate concrete was studied. Some efforts were taken to increase the resistance of lightweight aggregate concrete (LC) to water penetration by using the mineral admixtures of fly ash, granulated blast furnace slag or silica fume. Accelerated chloride penetrability test and liquid atmosphere press method were used to study the anti-permeability of lightweight aggregate concrete. The experimental results show that fly ash, granulated blast furnace slag and silica fume can decrease the permeability of lightweight aggregate concrete, but the effect of granulated blast furnace slag is poor. According to the SEM and pore structure analyzing results,an interface self-reinforcing effect model was presented and the reinforced mechanism of mineral mixture on LC was discussed according to the model described by authors.
基金Supported by China Postdoctoral Science Foundation
文摘The self-reinforced Si_3N_4 ceramics which contain Y_2O_3 and La_2O_3 additives have been prepared by hot-pressing. Under the optimum processing conditions, this material has the flexural strength of 960～1050MPa and the fracture toughness of 11.17～12.74MPa·m^(1/2) at room-temperature, and 720～780MPa and 22～24MPa·m^(1/2) at 1350℃. The effects of heat ing rate, sintering temperature, and holding time on the microstructures and mechanical properties are investigated. The experimental results show that an appropriate β-Si_3N_4 grain size and homogeneous microstructure can be obtained under the conditions of a heating rate of 10℃/min, sintering temperature of 1800℃, and holding time of 1h, which are advantageous to enhancing the mechanical properties. Crack deflection in large rodlike β-Si_3N_4 grains is a principle source of toughening.
