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RESEARCH ON VISUALIZATION OF FRACTURE PROCESS OF SUPER-HIGH-STRENGTH CONCRETE

超高强混凝土断裂过程可视化研究

基本信息

批准号：
03452219
负责人：
TOMOSAWA Fuminori
金额：
$ 2.62万
依托单位：
THE UNIVERSITY OF TOKYO
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

项目摘要

Mechanical properties of coarse aggregate such as compressive strength, modulus of elasticity and toughness are important for making super-high-strength concrete. In order to investigate the effect of coarse aggregate on compressive strength of super-high-strength concrete, plate specimens, in which a few types of artificial coarse aggregates were arranged in some ways, were tested in compression. When tested, the pictures of initiation and propagation of cracks under compression were taken, and the concentration and distribution of strain were measured by paper strain gauges. The test results are summarized as follows :1.In the case that modulus of elasticity of coarse aggregates are higher than that of mortar and bond strength between coarse aggregates and mortar is very small, bond cracks occur at the early stage of loading. If the bond strength exsists in some extent, bond cracks occur at the half level of maximum stress.2.In the case that compressive strength of coarse aggregates are higher than that of mortar, crack arresting by coarse aggregates cannot be expected if the content of coarse aggregates is small.3.In order to make super-high-strength concrete with compressive strength of more than 120 MPa, the attention should be payd to the followings.(1) Both coarse aggregate and mortar have compressive strength more than 120 MPa.(2) Difference of modulus of elasticity between coarse aggregate and mortar is small.(3) Coarse aggregate is tough.(4) Relatively large amount of coarse aggregate exsist.

粗骨料的抗压强度、弹性模量和韧性等力学性能是配制超高强混凝土的重要指标。为了研究人工粗骨料对超高强混凝土抗压强度的影响，进行了几种人工粗骨料不同排列方式的平板试件的抗压试验。试验时，拍摄了受压裂纹的萌生和扩展过程，并用纸应变片测量了应变的集中和分布。试验结果表明：1.当粗集料弹性模量大于砂浆弹性模量，且粗集料与砂浆之间的粘结强度很小时，在加载的早期，粗集料与砂浆之间的粘结就产生了裂缝。2.在粗骨料抗压强度高于砂浆抗压强度的情况下，粗骨料掺量较小时，粗骨料不能起到止裂的作用; 3.为了配制抗压强度大于120 MPa的超高强混凝土，粗骨料掺量越小，抗压强度越大，抗压强度越高，抗压强度越大，抗压强度越高，抗压强度越大，抗压强度越高，抗压强度越大，抗压强度越高，抗压强度越高，抗压强度越大，抗压强度越高，抗压强度越高，抗压强度越大，抗压强度越高，抗压强度越大，抗压强度越高，抗压强度越低，抗压强度越高，抗压强度越高，抗压强度越低，抗压强度越高，抗压强度越高。应注意以下几点。(1)粗骨料和砂浆的抗压强度均大于120 MPa。(2)粗集料与砂浆的弹性模量相差较小。(3)粗骨料很坚韧。(4)粗集料量较大。