单块石粒径对自密实混凝土断裂性能的影响研究  

Research on the effect of single rock size on the fracture performance of self-compacting concrete

作　　者：罗滔 李玉洁 杨毅[1] 潘晓凤 金峰[3] LUO Tao;LI Yujie;YANG Yi;PAN Xiaofeng;JIN Feng(Shanxi Key Laboratory of Safety and Durability of Concrete Structures,Xijing University,Xi’an 710123,China;College of Water Resources and Architectural Engineering,Northwest A&F University,Yangling 712100,China;State Key Laboratory of Hydroscience and Engineering,Tsinghua University,Beijing 100084,China)

机构地区：[1]西京学院陕西省混凝土结构安全与耐久性重点实验室,陕西西安710123 [2]西北农林科技大学水利与建筑工程学院,陕西杨凌712100 [3]清华大学水圈科学与水利工程国家重点实验室,北京100084

出　　处：《水利学报》2023年第10期1177-1187,共11页Journal of Hydraulic Engineering

基　　金：国家自然科学基金青年项目(51909223);国家自然科学基金重点项目(52039005);陕西省青年科技新星项目(2022KJXX-85);陕西省教育厅重点科学研究计划项目(22JS041);清华大学水圈科学与水利工程全国重点实验室开放基金项目(sklhse-2023-C-04)。

摘　　要：块石是堆石混凝土的重要组成成分,其粒径对自密实混凝土的断裂破坏具有显著影响。为研究块石粒径对自密实混凝土断裂性能的影响,对预埋不同粒径(20、25、30和35 mm)单块石的自密实混凝土进行了断裂韧性试验,并结合声发射(Acoustic Emission,AE)和数字图像相关技术(Digital Image Correlation,DIC)对试件断裂破坏过程进行动态监测,对比分析了块石粒径对自密实混凝土断裂性能的影响。研究结果表明:随块石粒径的增大,自密实混凝土起裂韧度呈现出先增大后减小的趋势,失稳韧度呈现出逐渐增大的趋势,与无块石试件相比,当块石粒径为30 mm时,起裂韧度、失稳韧度分别增大了10.8%、12.5%,块石阻裂效果明显;随块石粒径的增大,试件破坏产生的AE信号逐渐增多,峰值荷载处产生的AE振铃计数分别为无块石试件的39%、47%、63%、68%,峰后累计AE振铃计数分别为无块石试件的130%、140%、148%、164%;DIC结果显示,随块石粒径的增大,DIC测试区内最大水平位移逐渐增大,当块石粒径为35 mm时,最大水平位移为无块石试件的4倍;断裂过程区(Fracture Process Zone,FPZ)最大水平应变随块石粒径增大而逐渐增大。研究结果揭示了堆石混凝土中块石粒径对自密实混凝土裂缝扩展的影响机理,证明了堆石对自密实混凝土中裂缝发展的抑制作用。Rock is an important component of rock-filled concrete(RFC),and its size has a significant impact on the fracture failure of self-compacting concrete.In order to study the effect of rock size on the fracture performance,fracture toughness tests were carried out on self-compacting concrete embedded with single rock with different sizes(20 mm,25 mm,30 mm,35 mm).By combining acoustic emission(AE)and digital image correlation technology(DIC),the dynamic monitoring of the fracture process of specimens was carried out,and the effect of rock size on the fracture performance was compared and analyzed.The results show that as the size of the rock increases,the cracking toughness of self compacting concrete shows a trend of first increasing and then decreasing,while the instability toughness shows a gradual increasing trend.Compared with the specimens without rock,when the size of the rock is 30 mm,the cracking toughness and instability toughness increase by 10.8%and 12.5%respectively,and the rock has a significant crack resistance effect;As the size of the rock increases,the AE signals generated by specimen failure gradually increase.The AE ringing counts generated at the peak load are 39%,47%,63%,and 68%of the non-rock specimen,respectively.The cumulative AE ringing counts after the peak load are 130%,140%,148%,and 164%of the non-block specimen,respectively;The DIC results show that as the size of the rock increases,the maximum horizontal displacement in the DIC test area gradually increases.When the size of the rock is 35 mm,the maximum horizontal displacement is 4 times that of the non-rock specimen;The maximum horizontal strain in the fracture process zone(FPZ)gradually increases with the increase of rock size.The research results reveal the mechanism of the effect of rock size on the crack propagation of self-compacting concrete in rock-filled concrete,and demonstrate the inhibitory effect of rock-filled on the crack development of self-compacting concrete.

关 键 词：单块石粒径 自密实混凝土 堆石混凝土 断裂性能 阻裂机理 

分 类 号：TV41[水利工程—水工结构工程]