摘要
采用聚乙烯纤维(PE)和聚丙烯塑钢纤维(HPP)混杂技术制备纤维混凝土,以冻融前后的质量变化、动弹性模量、抗压强度以及弯曲性能等对其抗冻性能进行评价,并结合SEM分析从微结构角度对其损伤机理进行探讨.研究表明:冻融循环后素混凝土表面受损明显,混杂纤维掺入可以提高混凝土的完整性,表面损伤剥落减少;冻融循环过程中素混凝土的质量呈先增长后降低的趋势,而混杂纤维混凝土的质量呈持续增长状态;各配比混凝土的动弹性模量先基本不变而后下降,当纤维掺量为0.8%+1.2%时经受300次冻融循环作用后的相对动弹性模量仍保持在83.63%;各组混凝土抗压强度变化规律与动弹性模量相似;PE和HPP粗细纤维的协同作用使混凝土脆性显著改善,混杂纤维混凝土的韧性指数与残余强度随纤维掺量而变化,当掺量为0.8%+1.2%时优于理想弹塑性材料;经冻融作用后,混凝土的弯曲韧性有一定的损伤,但没有出现脆性断裂,仍表现出较好的延展性.
In this paper, first, hybrid fiber-reinforced concrete was prepared by using the hybrid fiber of polyethy-lene fiber （ PE ） and polypropylene plastic fiber （ HPP） . Then, the frost resistance of the reinforced concrete before and after the freeze-thaw process was investigated in terms of quality variation, dynamic elasticity modulus, com-pressive strength and flexural performance. Finally, the damage mechanism of the concrete was analyzed by using SEM analysis technique. The results show that （1） freeze-thaw cycles may cause obvious damage to plain concrete, and hybrid fiber can improve the integrity of concrete and decrease the surface damage; （2） the quality of plain concrete first increases and then decreases in the freeze-thaw cycle, while that of the hybrid fiber-reinforced con-crete continuously increases; （ 3 ） the dynamic elastic modulus of the concrete with different proportions almost re-mains unchanged at first and then decreases; （4） after 300 freeze-thaw cycles, the relative dynamic elastic modu-lus of the concrete with a fiber content of 0. 8 % ＋ 1 . 2 % still keeps at 83. 6 3 % ; （5） the variation rule of com-pressive strength is similar to that of the dynamic elastic modulus; （6） the synergistic effect of fine-PE and coarse HPP fibers significantly improves the brittleness of concrete ; （ 7 ） both the toughness index and the residual strength of hybrid fiber-reinforced concrete vary with the fiber content ; （ 8 ） the prepared reinforced concrete is superior to the ideal elastic-plastic material when the hybrid fiber content is 0. 8 % ＋1. 2 % ; and （9） freeze-thaw cycles may result in certain damage to the flexural toughness, but still no brittle fracture appears, and the concrete still posses-ses good ductility.
出处
《华南理工大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2017年第4期87-94,共8页
Journal of South China University of Technology(Natural Science Edition)
基金
国家自然科学基金资助项目(51508030)
中国博士后科学基金资助项目(2015M582592)
青海省重大科技专项(2014-GX-A2A)
长安大学中央高校基本科研业务费专项资金资助项目(310831162001
310831161001)~~
关键词
水泥混凝土
混杂纤维
抗冻性
弯曲軔性
微结构
cement concrete
hybrid fiber
frost resistance
flexural toughness
micro-structure
