多尺度混杂纤维增强珊瑚混凝土的单轴压缩性能  

Uniaxial Compressive Behavior of Multi-Scale Hybrid Fiber Reinforced Coral Concrete

作　　者：刘兵 李元举 王洋 明阳[1,2] 张轩煜 钱凯 LIU Bing;LI Yuanju;WANG Yang;MING Yang;ZHANG Xuanyu;QIAN Kai(Guangxi Key Laboratory of Green Building Materials and Construction Industrialization,Guilin University of Technology,Guilin 541004,Guangxi,China;School of Civil and Architectural Engineering,Guilin University of Technology,Guilin 541004,Guangxi,China;School of Civil Engineering,Central South University,Changsha 410075,China)

机构地区：[1]桂林理工大学,广西绿色建材与建筑工业化重点实验室,广西桂林541004 [2]桂林理工大学土木与建筑工程学院,广西桂林541004 [3]中南大学土木工程学院,长沙410075

出　　处：《硅酸盐学报》2024年第5期1543-1553,共11页Journal of The Chinese Ceramic Society

基　　金：广西科技基地与人才专项(桂科AD22035999);国家自然科学基金(52108201,U22A20244);广西自然科学基金(2021GXNSFBA220049,2021GXNSFFA196001);广西绿色建材与建筑工业化重点实验室(22-J-21-9);广西科技重大专项子课题(AA22068073-3)。

摘　　要：珊瑚混凝土是进行岛礁开发建设的重要建筑材料之一,多尺度混杂纤维掺入可从多尺度改善珊瑚混凝土的受力性能,从而拓展其应用范围。以碳纤维(CFs)和玄武岩纤维(BFs)作为微丝纤维、以塑钢纤维(PSFs)作为粗纤维制备了混杂纤维增强珊瑚混凝土(HFRCC),通过单轴压缩试验研究了其受力性能。结果表明:HFRCC的单轴受压全过程可分为线弹性、裂缝稳定发展、裂缝不稳定发展和峰后破坏4个阶段,微丝纤维主要在峰前裂缝发展阶段发挥作用,而粗纤维主要在峰后阶段发挥作用。综合考虑强度和韧性指标,当CFs、BFs体积掺量分别为0.15%,PSFs掺量为7 kg/m^(3)时,HFRCC表现出更优异的性能;与基准组相比,峰值应力、峰值应变和峰后压缩韧性分别提高了6.22%、38.54%和116.44%。基于CEB-FIP和过镇海的本构模型建立了适用于HFRCC的修正本构模型,模型计算曲线与实测曲线吻合较好。通过修正本构模型探讨了HFRCC的损伤演化过程,发现CFs、BFs和PSFs混杂掺入可以协同延缓珊瑚混凝土的损伤进程。Introduction Using coral concrete made from coral aggregates instead of conventional coarse and fine aggregates and seawater instead of freshwater for island reef construction can reduce costs and shorten the construction period for the development of the marine economy.However,coral concrete has some challenges such as high brittleness,poor toughness,and limited durability,thus restricting its application in engineering.Previous studies confirm that incorporating fibers can effectively enhance the mechanical properties of concrete.Therefore,in coral concrete,some microfibers with high elastic modulus are considered to reduce the microcracks,and some macro-fibers with high fracture toughness and elongation are considered to bridge the macrocracks,enhancing its mechanical performance in multiple scales.Carbon fibers(CFs)have the maximum elasticity modulus among commonly used micro-fibers.However,replacing carbon fibers with more economical and relatively high-modulus basalt fibers(BFs)is an effective approach.In this paper,CFs and BFs were selected as microfibers.High-elongation plastic steel fibers(PSFs)were also selected as macro-fibers instead of the steel fibers most commonly used in concrete.The CFs,BFs,and PSFs were incorporated into coral concrete.The mechanical properties of the hybrid fibers-reinforced coral concrete(HFRCC)under axial compression were investigated,and the corresponding constitutive model was proposed.Methods Cement used was ordinary Portland cement P·O 42.5,adhering to the code GB175.A coarse aggregate used was a crushed coral with a continuous gradation of 5 mm to 20 mm and a tube compressive strength of 3.1 MPa.A fine aggregate used was a coral sand with a fineness modulus of 3.0.Seawater was taken from Beibu Gulf,Guangxi,China.The admixtures include a polycarboxylate superplasticizer,a hydroxypropyl methyl cellulose(HPMC),and an antifoaming agent.The study involved sixteen mix proportions for HFRCCs with different dosages of CFs,BFs and PSFs.A uniaxial compression test was conducted o

关 键 词：本构模型 压缩韧性 协同效应 损伤演化 珊瑚混凝土 混杂纤维 

分 类 号：TU528[建筑科学—建筑技术科学]