Monolithic refractory castables comprising a hydraulic bond are still used in a vast majority of cases because of their flexibility and robustness,despite many developments for chemical as well as non-cement castable ...Monolithic refractory castables comprising a hydraulic bond are still used in a vast majority of cases because of their flexibility and robustness,despite many developments for chemical as well as non-cement castable binders.The drying can however be a challenge,in particular for deflocculated dense castables of the low cement castable range.Many publications have been released on this topic for the last ten years,but they often focused on the drying mechanisms or on the addition of drying aids.This paper presents some experimental results on the effect of the composition on the drying properties,especially on the effect of silicon carbide,used for its high thermal conductivity,and on the matrix system.It also introduces two laboratory tests to study and iteratively improve the drying schedule of a given castable lining.The results show that the spalling resistance and the vapor pressure build-up are significantly influenced by the formulation.It is also shown that the castable properties after drying can be altered if the heating rate is very high.展开更多
The characteristics of surface appearances,mass loss,relative dynamic modulus of elasticity and strength loss of different recycled aggregate concretes(RAC) exposed to freeze-thaw cycles were analyzed.It was found tha...The characteristics of surface appearances,mass loss,relative dynamic modulus of elasticity and strength loss of different recycled aggregate concretes(RAC) exposed to freeze-thaw cycles were analyzed.It was found that the freeze-thaw resistance of RAC could be determined by the recycled aggregate compositions and admixtures.Both the saturation degree and the air void structure were the key factors influencing the freeze-thaw damage on concrete.Some major proposed freeze-thaw deterioration mechanisms were utilized to interpret the freeze-thaw damage on recycled aggregate concrete.Meanwhile,some potential measures to enhance the freeze-thaw resistance of concrete were summarized and discussed.展开更多
Poly(vinyl alcohol)(PVA)is biodegradable,recyclable,and has high tensile strength.Therefore,it is ideal for the development of environment-friendly sustainable bioplastics.However,at elevated humidity,the mechanical p...Poly(vinyl alcohol)(PVA)is biodegradable,recyclable,and has high tensile strength.Therefore,it is ideal for the development of environment-friendly sustainable bioplastics.However,at elevated humidity,the mechanical properties of PVA bioplastic films undergo degradation owing to their intrinsic hydrophilic and hygroscopic nature,hindering their applications.This study proposes a nanoconfined assembly strategy to produce humidity-adaptive,mechanically robust,and recyclable bioplastic film.The strong hydrogen bonds between PVA and cellulose nanofibrils inhibit the penetration of water molecules into the film to promote humidity resistance.Further,the robust coordination interactions between bentonite nanoplates,PVA,and cellulose nanofibrils restrict the slip of polymer chains during deformation,leading to enhanced mechanical properties.Benefiting from the nanoconfined assembly architecture in aggregated composites,the resulting reinforced PVA film simultaneously exhibits strength,stiffness,toughness,fracture energy,and tearing energy of 55.9 MPa,1,275.6 MPa,162.9 MJ m^(−3),630.9 kJ m^(−2),and 465.0 kJ m^(−2),respectively.Moreover,the film maintains a strength of approximately 48.7 MPa even at 80%relative humidity for 180 days.This efficient design strategy applies to diverse scales and structured cellulose biomacromolecules.Moreover,it facilitates the application of recyclable high-performance bioplastic films to settings that require high humidity tolerance.展开更多
文摘Monolithic refractory castables comprising a hydraulic bond are still used in a vast majority of cases because of their flexibility and robustness,despite many developments for chemical as well as non-cement castable binders.The drying can however be a challenge,in particular for deflocculated dense castables of the low cement castable range.Many publications have been released on this topic for the last ten years,but they often focused on the drying mechanisms or on the addition of drying aids.This paper presents some experimental results on the effect of the composition on the drying properties,especially on the effect of silicon carbide,used for its high thermal conductivity,and on the matrix system.It also introduces two laboratory tests to study and iteratively improve the drying schedule of a given castable lining.The results show that the spalling resistance and the vapor pressure build-up are significantly influenced by the formulation.It is also shown that the castable properties after drying can be altered if the heating rate is very high.
基金Funded by the National Key Research and Development Program of China during the“13th Five-Year Plan”(No.2018 YFD1101001)。
文摘The characteristics of surface appearances,mass loss,relative dynamic modulus of elasticity and strength loss of different recycled aggregate concretes(RAC) exposed to freeze-thaw cycles were analyzed.It was found that the freeze-thaw resistance of RAC could be determined by the recycled aggregate compositions and admixtures.Both the saturation degree and the air void structure were the key factors influencing the freeze-thaw damage on concrete.Some major proposed freeze-thaw deterioration mechanisms were utilized to interpret the freeze-thaw damage on recycled aggregate concrete.Meanwhile,some potential measures to enhance the freeze-thaw resistance of concrete were summarized and discussed.
基金National Natural Science Foundation of China,Grant/Award Number:31890774Forestry Science and Technology Innovation and Extension Project of Jiangsu Province,Grant/Award Number:LYKJ[2021]04。
文摘Poly(vinyl alcohol)(PVA)is biodegradable,recyclable,and has high tensile strength.Therefore,it is ideal for the development of environment-friendly sustainable bioplastics.However,at elevated humidity,the mechanical properties of PVA bioplastic films undergo degradation owing to their intrinsic hydrophilic and hygroscopic nature,hindering their applications.This study proposes a nanoconfined assembly strategy to produce humidity-adaptive,mechanically robust,and recyclable bioplastic film.The strong hydrogen bonds between PVA and cellulose nanofibrils inhibit the penetration of water molecules into the film to promote humidity resistance.Further,the robust coordination interactions between bentonite nanoplates,PVA,and cellulose nanofibrils restrict the slip of polymer chains during deformation,leading to enhanced mechanical properties.Benefiting from the nanoconfined assembly architecture in aggregated composites,the resulting reinforced PVA film simultaneously exhibits strength,stiffness,toughness,fracture energy,and tearing energy of 55.9 MPa,1,275.6 MPa,162.9 MJ m^(−3),630.9 kJ m^(−2),and 465.0 kJ m^(−2),respectively.Moreover,the film maintains a strength of approximately 48.7 MPa even at 80%relative humidity for 180 days.This efficient design strategy applies to diverse scales and structured cellulose biomacromolecules.Moreover,it facilitates the application of recyclable high-performance bioplastic films to settings that require high humidity tolerance.
