The electrical conductivity and piezoresistivity of carbon fiber graphite cement-matrix composites（CFGCC） with carbon fiber content（1% by the weight of cement）,graphite powder contents （0%-50% by the weight of ce...The electrical conductivity and piezoresistivity of carbon fiber graphite cement-matrix composites（CFGCC） with carbon fiber content（1% by the weight of cement）,graphite powder contents （0%-50% by the weight of cement） and CCCW（cementitious capillary crystalline waterproofing materials,4% by the weight of cement） were studied.The experimental results showed that the relationship between the resistivity of CFGCC and the concentration of graphite powders had typical features of percolation phenomena.The percolation threshold was about 20%.A clear piezoresistive effect was observed in CFGCC with 1wt% of carbon fibers,20wt% or 30wt% of graphite powders under uniaxial compressive tests,indicating that this type of smart composites was a promising candidate for strain sensing.The measured gage factor （defined as the fractional change in resistance per unit strain） of CFGCC with graphite content of 20wt% and 30wt% were 37 and 22,respectively.With the addition of CCCW,the mechanical properties of CFGCC were improved,which benefited CFGCC piezoresistivity of stability.展开更多
混凝土吸水性是影响混凝土耐久性能的重要因素。采用相同配合比配制C30混凝土,对不同养护龄期、不同防水材料涂量混凝土进行吸水试验,研究水泥基渗透结晶型防水材料对C30混凝土吸水性能的影响。试验结果表明:防水材料涂量对吸水性能的...混凝土吸水性是影响混凝土耐久性能的重要因素。采用相同配合比配制C30混凝土,对不同养护龄期、不同防水材料涂量混凝土进行吸水试验,研究水泥基渗透结晶型防水材料对C30混凝土吸水性能的影响。试验结果表明:防水材料涂量对吸水性能的影响要大于养护龄期;养护龄期对吸水性能略有影响,龄期越长混凝土吸水性越差;试验中混凝土吸水8 h内,混凝土吸水量与测试时间的平方根成线性关系,超过8 h后,混凝土吸水量增大,慢慢趋于稳定;随着防水材料涂量的增加,混凝土吸水量明显减小,建议最佳涂量为250 m L/m^2。展开更多
基金Funded by the National Natural Science Foundation of China(No.50878170 and No. 10672128)
文摘The electrical conductivity and piezoresistivity of carbon fiber graphite cement-matrix composites（CFGCC） with carbon fiber content（1% by the weight of cement）,graphite powder contents （0%-50% by the weight of cement） and CCCW（cementitious capillary crystalline waterproofing materials,4% by the weight of cement） were studied.The experimental results showed that the relationship between the resistivity of CFGCC and the concentration of graphite powders had typical features of percolation phenomena.The percolation threshold was about 20%.A clear piezoresistive effect was observed in CFGCC with 1wt% of carbon fibers,20wt% or 30wt% of graphite powders under uniaxial compressive tests,indicating that this type of smart composites was a promising candidate for strain sensing.The measured gage factor （defined as the fractional change in resistance per unit strain） of CFGCC with graphite content of 20wt% and 30wt% were 37 and 22,respectively.With the addition of CCCW,the mechanical properties of CFGCC were improved,which benefited CFGCC piezoresistivity of stability.
文摘混凝土吸水性是影响混凝土耐久性能的重要因素。采用相同配合比配制C30混凝土,对不同养护龄期、不同防水材料涂量混凝土进行吸水试验,研究水泥基渗透结晶型防水材料对C30混凝土吸水性能的影响。试验结果表明:防水材料涂量对吸水性能的影响要大于养护龄期;养护龄期对吸水性能略有影响,龄期越长混凝土吸水性越差;试验中混凝土吸水8 h内,混凝土吸水量与测试时间的平方根成线性关系,超过8 h后,混凝土吸水量增大,慢慢趋于稳定;随着防水材料涂量的增加,混凝土吸水量明显减小,建议最佳涂量为250 m L/m^2。
