高温后纳米改性水泥基材料的残余抗折强度  

The effects of high temperature on flexural strengths of high performance nano-modified cementitious composites

作　　者：付晔[1] 李庆华[1] 徐世烺[1] 

机构地区：[1]浙江大学建筑工程学院,杭州310058

出　　处：《深圳大学学报（理工版）》2014年第2期187-192,共6页Journal of Shenzhen University(Science and Engineering)

基　　金：国家科技支撑计划资助项目(2012BAJ13B04)~~

摘　　要：对6种不同掺量钢纤维和PVA纤维组合的纳米改性水泥基材料(high performance nano-modified cementitious composites,HPNCC)高温后的抗折强度进行试验研究,探讨不同高温(200、400、600和800℃)对HPNCC抗折强度、质量损失和微观结构的影响,寻求试验范围内钢纤维与PVA纤维的最佳掺量组合.研究结果表明,经历200℃高温1 h后,HPNCC质量损失平均为3.90%,抗折强度略有降低,微观结构没有明显变化;经历400℃高温1 h后,由于HPNCC质量损失大幅增加(平均为15.60%)及内部的PVA纤维融化、毛细孔水分蒸发、孔洞扩张和水泥基基体劣化,其抗折强度急剧下降;经历600℃高温1 h后,HPNCC质量损失减缓,平均为16.89%,PVA纤维完全融化、挥发,抗折强度下降明显;经历800℃高温1 h后,微观结构进一步劣化,最优配比HPNCC的抗折强度保留36.52%.The influence of micro polyvinyl alcohol （ PVA） fibers and steel fibers on fire resistance, microstructures and mass loss of high performance nano-modified cementitious composite （ HPNCC） is discussed. Specimens contai-ning two different contents of PVA fibers and three different contents of steel fibers are examined. The specimens are exposed to a series of temperatures （200, 400, 600 and 800 ℃）. The fire resistance of mixtures are quantified in terms of the residual mechanical properties （ flexural strengths, deflection and stiffness） and mass loss. The micro-structure characterization after exposure to fire is examined by scanning electron microscopy. Results indicate that af-ter HPNCC is exposed to 200 ℃ for an hour, average mass loss of HPNCC is 3. 90% while there is little change in flexural strength;after 400℃ exposure for an hour, average mass loss of HPNCC sharply reaches 15. 60% and flex-ural strength drops obviously for melting of PVA fibers and degradation of cement matrix;after HPNCC is exposed to 800℃ for an hour, the optimal composition of HPNCC reserve is up to 36. 52% of flexural strength.

关 键 词：建筑材料 残余抗折强度 水泥基复合材料 混杂纤维 纳米改性 微观结构 

分 类 号：TU525[建筑科学—建筑技术科学]