In this paper the coefficient and law of the size effect of RPC were studied through experiments and theoretical analysis. The size-effect coefficients for the compressive strength of RPC are deduced through experimen...In this paper the coefficient and law of the size effect of RPC were studied through experiments and theoretical analysis. The size-effect coefficients for the compressive strength of RPC are deduced through experiments.They indicate that RPC without fiber behaves quite the same as normal or high strength concrete.The size effect on compressive strength is more prominent in RPC containing fiber.Bazant's size effect formula of compressive strength applies to RPC.A formula is given to predict the compressive strength of cubic RPC specimens 100 mm on a side where the fiber dosage ranges from 0-2%.展开更多
The internal length scale(ILS)is a dominant parameter in strain gradient plasticity(SGP)theories,which helps to successfully explain the size effect of metals at the microscale.However,the ILS is usually introduced in...The internal length scale(ILS)is a dominant parameter in strain gradient plasticity(SGP)theories,which helps to successfully explain the size effect of metals at the microscale.However,the ILS is usually introduced into strain gradient frameworks for dimensional consistency and is model-dependent.Even now,its physical meaning,connection with the microstructure of the material,and dependence on the strain level have not been thoroughly elucidated.In the current work,Aifantis'SGP model is reformulated by incorporating a recently proposed power-law relation for strain-dependent ILS.A further extension of Aifantis'SGP model by including the grain size effect is conducted according to the Hall-Petch formulation,and then the predictions are compared with torsion experiments of thin wires.It is revealed that the ILS depends on the sample size and grain size simultaneously;these dependencies are dominated by the dislocation spacing and can be well described through the strain hardenmg exponent.Furthermore,both the original and generalized Aifantis models provide larger estimated values for the ILS than Fleck-Hutchinson's theory.展开更多
基金Project 50508005 supported by the National Natural Science Foundations of China
文摘In this paper the coefficient and law of the size effect of RPC were studied through experiments and theoretical analysis. The size-effect coefficients for the compressive strength of RPC are deduced through experiments.They indicate that RPC without fiber behaves quite the same as normal or high strength concrete.The size effect on compressive strength is more prominent in RPC containing fiber.Bazant's size effect formula of compressive strength applies to RPC.A formula is given to predict the compressive strength of cubic RPC specimens 100 mm on a side where the fiber dosage ranges from 0-2%.
文摘The internal length scale(ILS)is a dominant parameter in strain gradient plasticity(SGP)theories,which helps to successfully explain the size effect of metals at the microscale.However,the ILS is usually introduced into strain gradient frameworks for dimensional consistency and is model-dependent.Even now,its physical meaning,connection with the microstructure of the material,and dependence on the strain level have not been thoroughly elucidated.In the current work,Aifantis'SGP model is reformulated by incorporating a recently proposed power-law relation for strain-dependent ILS.A further extension of Aifantis'SGP model by including the grain size effect is conducted according to the Hall-Petch formulation,and then the predictions are compared with torsion experiments of thin wires.It is revealed that the ILS depends on the sample size and grain size simultaneously;these dependencies are dominated by the dislocation spacing and can be well described through the strain hardenmg exponent.Furthermore,both the original and generalized Aifantis models provide larger estimated values for the ILS than Fleck-Hutchinson's theory.
