Quantitative evaluation of segregation behaviors of fresh concrete and influential factors on them

新拌混凝土离析行为的定量评价及其影响因素

基本信息

批准号：
16360214
负责人：
YAMAMOTO Yasuhiko
金额：
$ 6.78万
依托单位：
University of Tsukuba
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-16360214/
关键词：
fresh concrete granular materials mechanical law segregation bleeding segregation resistibility model segregation test pore water pressure 材料分離数値解析せん断実験分離構成則多相モデル LAT実験

项目摘要

This research aims to clarify quantitatively the segregation behaviors of fresh concrete by a microscopic approach, and to develop a segregation resistibility test method. The results of present work can be summarized as follows.(1)One-side shear test apparatus incorporating laser irradiation device was made and used to examine, by means of Laser-Aided-Tomography, the movement of irregular particles under shear force. The observed information such as changes in contact angles and moving distance of the particles were used for later theoretical parts of this work.(2)Characteristics and behavior of granular materials in fresh concrete were theoretically investigated based on the multi-phase structural model, which had been proposed by Li, co-operator of present work, to clarify mechanical constitutive laws of fresh concrete under both non-vibrated and vibrated conditions, and a non-linear deformation resistibility model of fresh concrete was proposed.(3)Using the mechanical constitutive … More laws, segregation behaviors of coarse aggregate particles in fresh concrete were investigated to formulate their mean sedimentation rate for the cases where concrete was in a standstill or vibrated state or in the state of deforming and/or flowing. Also, effects of various factors on the segregation rate, including mean particle size, fluidity of fresh concrete, elapsed time, difference in density between coarse aggregate and matrix mortar, normal stress, and others were quantitatively clarified.(4)After formulating pore water pressure and its change with time for fresh concrete in both static and vibrated states, equations for expressing both amount and rate of bleeding were derived by applying Darcy Law to bleeding of fresh concrete, and factors influencing on the bleeding phenomena were quantitatively clarified.(5)A formula of deviation ratio of gravity center, which could be used to evaluate the degree of segregation of fresh concrete, was deduced, and a segregation resistibility model was suggested for fresh concrete in static state.(6)A series of shear tests were made to verify the mechanical constitutive law of fresh concrete using an apparatus which was a stratified shear box incorporated with an γ-ray density meter. This apparatus was proposed for testing the segregation resistibility of fresh concrete. Less

这项研究旨在通过微观方法定量地阐明新鲜混凝土的隔离行为，并开发一种隔离性测试方法。（1）编码激光辐照装置的一侧剪切测试设备可以概括当前工作的结果，并用激光辅助训练术在剪切力下进行了不规则颗粒的运动。基于多相结构模型，对观察到的信息（例如接触角的变化和颗粒的移动距离都用于后来的理论部分。提出了新鲜混凝土的耐药性模型。（3）研究了新鲜混凝土中粗骨料颗粒的越来越多的法律，在混凝土处于静止状态或振动状态或在不当和/或流动状态的情况下，研究了新鲜混凝土中粗骨料颗粒的隔离行为。此外，各种因素对隔离率的影响，包括平均粒径，新鲜混凝土的流动性，经过的时间，粗骨料和基质砂浆之间的密度差异，正常压力，正常压力和其他因素被定量地夹住。（4）在制定孔隙水压力以及在静态和振动状态下均应驱动量和振动的时间变化后，静态和振动的速度均已变化，并逐渐振动，并在静止的状态下，均匀的速率，用于be的速度，并将其用于静态的混凝土，并将其用于稳定的量化，并在静态的水平上均应降低量化的量化。新鲜混凝土的出血和因素对出血现象的影响进行了定量clas。（5）重力中心出发比例的一个公式，可用于评估新鲜混凝土的隔离程度，并推导出新的混凝土隔离程度，并提出了一种在静态状态中进行隔离的隔离模型（6）semertial semertial semertial semertial selets semert semert semert seartic seart seart seart seart seart sear semert sear sement seart seart sement seart seart。混凝土使用具有γ射线密度计的分层剪切盒的混凝土。提出了该设备用于测试新鲜混凝土的隔离耐药性。较少的