应变硬化水泥基复合材料性能与应用研究进展  

A Review on Performance and Application of Strain Hardening Cementitious Composites

作　　者：高淑玲 王文昌 GAO Shuling;WANG Wenchang(School of Civil Engineering and Transportation, Hebei University of Technology, Tianjin 300401;Civil Engineering Technology Research Center of Hebei Province, Tianjin 300401)

机构地区：[1]河北工业大学土木与交通学院,天津300401 [2]河北省土木工程技术研究中心,天津300401

出　　处：《材料导报》2019年第21期3620-3629,共10页Materials Reports

基　　金：国家自然科学基金(51108151)~~

摘　　要：混凝土作为典型的脆性材料,在拉伸荷载作用下呈现应变软化现象,这种不理想的失效模式会对工程结构的受力性能和耐久性能产生不利影响。通过在微观尺度上对材料进行设计,综合考虑纤维、基体和纤维/基体界面三者之间的相互作用,制备了应变硬化水泥基复合材料(SHCC)。这是一种新型的高性能纤维增强水泥基材料,相较于传统的纤维混凝土,SHCC具有两大显著优势:一是拉伸应变硬化,二是破坏失效前会产生多条细密裂缝。高延性使SHCC力学性能优良,细密裂缝有效保证了其耐久性,近年来相关的研究工作已取得了一定的进展。研究初期,以材料设计理论为指导使SHCC达到预定的硬化效果。纤维桥联法则是其理论基础,为了实现应变硬化,必须满足两个准则:强度准则和能量准则。设计较为完善的材料的各项力学性能指标可为工程应用提供关键信息。高强、高韧是研究者们不懈追求的目标之一,目前,已经成功设计出抗压强度高达115 MPa、极限拉应变达到8%的SHCC,而且该复合材料的大多数裂缝宽度在100 μm以下,裂缝间距不超过 2 mm 。关于SHCC断裂性能的研究具有挑战性,在多缝开裂阶段仍缺乏行之有效的分析手段。霍普金森杆冲击试验表明,SHCC是与应变率相关的材料,峰值应力明显随着应变率的增加而增大。在承受疲劳荷载作用时,SHCC表现出延性破坏特征,疲劳寿命相对较长。当工程结构的服役周期较长时,材料的耐久性问题不容忽视。由于SHCC的裂缝宽度较小,水分的渗透量会大幅下降,2%拉应变水平下其渗透系数只有2.10×10^-7 m/s,其自愈合行为还会进一步改善渗透性。SHCC还为极端温度条件下的应用提供了可能,经受300次冻融循环后其各项性能均保持在较高水平;历经高温后纤维发生熔融留下蒸汽压力释放的通道,避免了材料的高温爆裂。此外,实际工程的检验客观A s a typical brittle material, concrete exhibits strain softening under tensile load. The unfavorable failure mode can adversely affect the mechanical properties and durability of engineering structure. By material design on a micro scale, strain hardening cementitious composites (SHCC)were developed by designing materials on a microscopic scale and considering the interaction between fiber, matrix and fiber/matrix interface. This is a new type of high performance fiber reinforced cementitious composites. Compared with the traditional fiber reinforced concrete, SHCC has two significant advantages: one is tensile strain hardening, and the other is the multiple micro-cracks before failure. High ductility makes it excellent in mechanical properties, and tight cracks effectively ensure durability. In recent years, the relevant research works have made great progress. At the initial stage of research, the material design theory guides it to achieve the desired results. The fiber-bridging law is the theoretical basis of SHCC. In order to achieve strain hardening, two criteria must be satisfied-strength criterion and energy criterion. After the material design is refined, various mechanical performance indicators can provide key information for engineering applications. High strength and high toughness material is one of the unremitting pursuits of researchers. At present, SHCC with compressive strength up to 115 MPa and ultimate tensile strain of 8% has been successfully designed. Moreover, most crack widths are maintained under 100 μm with the crack spacing less than 2 mm. Research on the fracture properties of SHCC is challenging, and there is still a lack of effective analytical methods in the multi-cracking stage. The split Hopkinson pressure bar test showed that SHCC is a strain rate dependence material, and the peak stress increased obviously with the increase of strain rate. Subjected to fatigue loading, SHCC exhibited ductile failure characteristics and relatively high fatigue life. At the same time, consider

关 键 词：应变硬化水泥基复合材料 纤维 材料性能 耐久性 工程应用 

分 类 号：TU528[建筑科学—建筑技术科学]