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
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.
