高强度高延性水泥基复合材料的弯曲性能  

Flexural properties of high strength high ductility cementitious composite

作　　者：吴立山 余志辉 袁振 张聪[1,2] WU Lishan;YU Zhihui;YUAN Zhen;ZHANG Cong(Jiangnan University, School of Environment and Civil Engineering, Wuxi 214000, China;Jiangsu Key Laboratory of Environmental Impact and Structural Safety in Engineering, Xuzhou 221000, China)

机构地区：[1]江南大学环境与土木工程学院,江苏无锡214000 [2]江苏省土木工程环境灾变与结构可靠性重点实验室,江苏徐州221000

出　　处：《功能材料》2021年第12期12159-12164,共6页Journal of Functional Materials

基　　金：国家自然科学基金项目(51908247);江苏省土木工程环境灾变与结构可靠性重点实验室开放基金项目(KFJJ202007)。

摘　　要：高强度高延性水泥基复合材料(HSHDCC)由于具有超高强度和超高延性等优异的力学性能,近年来在建筑结构抗震加固和修复领域得到了广泛的关注。但是,HSHDCC的高成本是其大规模工程化应用的瓶颈之一。通过引入高强度高弹性模量低成本的碳酸钙晶须,制备了新型的HSHDCC材料,研究了水胶比和碳酸钙晶须对HSHDCC弯曲性能的影响。研究发现,HSHDCC的抗弯强度随水胶比的增大而降低,但其延性随水胶比的增大而提高,HSHDCC的弯曲裂缝随水胶比的增大而逐渐饱和。引入碳酸钙晶须改善了HSHDCC的抗弯性能,碳酸钙晶须通过晶须拔出、裂纹偏转和裂纹桥联等微观作用机制产生更多的微裂源,提高裂缝的稳定扩展能力,从而改善HSHDCC的多缝开裂能力和弯曲挠度硬化行为,HSHDCC的延性得到了显著提升。High strength high ductility cementitious composite(HSHDCC)has attracted extensive attention in the field of seismic reinforcement and repair of building structures due to its excellent mechanical properties such as ultra-high strength and ultra-high ductility.However,the high cost of HSHDCC is one of the bottlenecks of its large-scale engineering application.In this paper,a novel HSHDCC material is prepared by introducing calcium carbonate whisker with high strength,high elastic modulus and low cost.The effects of water-binder ratio and calcium carbonate whisker on the flexural properties of HSHDCC are studied.The results indicate that the flexural strength of HSHDCC decreases with the increase of water-binder ratio,but its ductility improves with the increase of water-binder ratio.The flexural cracks of HSHDCC become saturated gradually with the increase of water-binder ratio.The introduction of calcium carbonate whisker improves the flexural properties of HSHDCC.The calcium carbonate whisker generates more micro-crack sources through the micro-mechanism of whisker pull-out,crack deflection and crack bridging,and improves the stability of crack propagation,thus improving the multiple cracking capacity and flexural deflection hardening behavior of HSHDCC.Therefore,the ductility of designed HSHDCC is significantly improved.

关 键 词：高强高延性水泥基复合材料 聚乙烯纤维 碳酸钙晶须 混杂纤维 弯曲性能 

分 类 号：TU502[建筑科学—建筑技术科学]