权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Role of Fine Mineral Powders to Produce High-Performance Concrete

精细矿物粉末在生产高性能混凝土中的作用

基本信息

批准号：
11650469
负责人：
SHOYA Masami
金额：
$ 1.86万
依托单位：
Hachinohe Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11650469/
关键词：
High-performance concretes Fine mineral powder Bleeding Water retentivity Water retaining factor Character of powder particle Interfacial zone High durable concrete

项目摘要

In recent years, it has been pointed out that concrete structures are likely suffer the attacks due to excess load and aggravated environment, and various function and performance for them are required. Given this background, High-performance concrete with high strength, high durability and self-compacting has been developed. Fine mineral powder is considered to play an important key factor to produce these high-performance concretes. The purpose of this study is to investigate the role of water retentivity of fine mineral powder to make the concrete with high quality such as high durability. Test results are summarized as follows ;1. Characters of fine mineral powders, such as specific surface area by BET, particle size distribution, shape factor and percentage of void, are evaluated.2. The capability to retain water by the fine mineral powders is examined to estimate water retaining factors which were definea from flow test, bleeding test and centrifugation test using powder paste. M … More utual relationships are investigated not only among the water retaining factors but also between these factors and physical properties of the powders.3. The effect for improving amount and rate of concrete bleeding is studied using nine fine mineral powders which are replaced some the volume of sand. The effect to reduce the bleeding of concrete by the powder is closely related to its capability to retain water. Effect of fine mineral powder incorporated on reduction of concrete bleeding could be estimated by water retaining factor defined in these powder paste tests.4. Water with air voids in fleshly placed concrete will be moved toward the surface. When the bleeding is excessive, harmful effects will arise on production of defects such as the formation of water channels and water pockets beneath the coarse aggregates, and the spacing factor was increased near the surface layer of concrete.5. The bleeding of concrete broadly influences interfacial zone of coarse aggregates in concrete. Especially, at the 20mm〜40mm from placed side of concrete, the weakness zone around coarse aggregates is increased. The weakness zone will result in less frost resistance of concrete.6. The application of mineral fine powders is very effective to make proper air-void system, to form the fine pore structures and to control the weakness zone around coarse aggregates, and it was very important for make the high durable concrete. Less

近年来，人们指出混凝土结构可能会受到超载和环境恶化的影响，对混凝土结构提出了各种功能和性能要求。在这种背景下，高强、高耐久、自密实的高性能混凝土应运而生。细矿粉被认为是生产这些高性能混凝土的重要关键因素。本研究旨在探讨矿物细粉保水性的作用，以制造高品质的混凝土，如高耐久性。测试结果总结如下：1.评价了矿物微粉的比表面积、粒度分布、形状因子和空隙率等性能.通过流动试验、泌水试验和粉浆离心试验确定了细矿粉的保水性能，并以此估算了其保水系数。M ...更多信息研究了保水因素之间的相互关系以及保水因素与粉体物理性能之间的相互关系.研究了用九种矿物微粉代替一定量的砂对提高混凝土泌水量和泌水率的效果。干粉减少混凝土泌水的效果与其保水能力密切相关。掺入矿物细粉减少混凝土泌水的效果可以通过粉浆试验中定义的保水因子来评价.混凝土中的水和空气空隙将被移向表面。当泌水量过大时，会对混凝土产生不利的影响，如在粗集料下形成水通道和水囊等缺陷，并使混凝土表层附近的间距系数增大.混凝土泌水对混凝土中粗集料界面区有着广泛的影响。特别是在距混凝土浇筑面20 mm ~ 40 mm处，粗骨料周围的薄弱区增大。混凝土的薄弱区会导致混凝土的抗冻性降低.矿物细粉的应用能有效地形成合适的空隙体系，形成细小的孔结构，控制粗集料周围的薄弱区，对配制高耐久性混凝土具有重要意义。少