矿物掺合料抑制桥梁混凝土徐变和损伤发展的试验研究  

Experimental Study on Mineral Admixture Inhibiting Creep and Damage Development of Bridge Concrete

作　　者：张文京 ZHANG Wenjing(NingboMunicipal Engineering Construction Group Co.,Ltd,Ningbo 315012,China)

机构地区：[1]宁波市政工程建设集团股份有限公司,浙江宁波315012

出　　处：《粉煤灰综合利用》2020年第6期94-100,共7页Fly Ash Comprehensive Utilization

摘　　要：以QL大桥维修改造工程项目为工程背景,对0、10%、20%、30%、40%不同磨细矿渣掺合量情况下的桥梁混凝土进行了徐变及损伤耦合试验,探讨矿物掺料对抑制桥梁混凝土徐变和损伤发展的影响。研究结果表明:随着磨细矿渣掺量的增加,混凝土的强度呈先增加后减小的变化特征,当掺量为20%时,混凝土的强度最高;当磨细矿渣的掺量为30%时,其抑制混凝土徐变和损伤发展的能力最佳,徐变度C t和损伤值D分别较基准试验组降低约29.5%和36.5%;电镜扫描试验显示:矿物掺合料的掺入增加了颗粒与基建面之间的胶结程度,但是当掺量为40%时,反而会呈现结构的松散状态,导致较差的界面结合状态;基于B3模型和Weibull分布理论,结合试验数据,建立起考虑磨细矿渣掺量影响的桥梁混凝土徐变损伤模型,该模型可较好模拟不同掺量情况下混凝土的线性和非线性徐变特征;综合试验研究成果,建议项目采用20%~25%掺量的配比应用于工程施工当中,即可保证设计强度,又能起到较好抑制徐变和损伤发展的作用。Based on the engineering background of "QL Bridge Maintenance and Reconstruction Project",the creep and damage coupling tests of bridge concrete with 0,10%,20%,30% and 40% different amount of ground slag were carried out,and the influence of mineral admixture on the creep and damage development of bridge concrete was discussed. The results show that with the increase of the content of ground slag,the strength of concrete increases at the first and then decreases. When the content of ground slag is 20%,the strength of concrete is the highest. When the content of ground slag is 30%,the ability of restraining concrete creep and damage development is the best. The creep degree Ctand damage value D are compared with the benchmark test. The experimental group decreased by about 29. 5% and 36. 5%. The scanning electron microscope test showed that the mineral admixture increased the cementation degree between the particles and the base surface,but when the content of mineral admixture was 40%,the structure would be loose,resulting in poor interface bonding state. Based on the B3 model and Weibull distribution theory,combined with the experimental data,the model was established. The creep damage model of bridge concrete considering the influence of the content of ground slag was established,which can simulate the linear and non-linear creep characteristics of concrete under different content of ground slag. Based on the comprehensive experimental research results,it suggested that the 20% ~ 25%proportion of slag should be used in the project construction to ensure the design strength and possibly rise again,to better inhibit the development of creep and damage.

关 键 词：磨细矿渣 掺量 电镜扫描 损伤 徐变度 模型 

分 类 号：TU528[建筑科学—建筑技术科学]