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Investigation on Frost Deterioration of Concrete Using Limestone Coarse Aggregate

石灰石粗骨料混凝土冻害试验研究

基本信息

批准号：
10650552
负责人：
SENBU Osamu
金额：
$ 1.86万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

Although limestone is characterized by low water absorption and high specific gravity, it is said that frost durability of concrete with the limestone coarse aggregate is lower than concrete with the good coarse aggregates. In this paper, frost durability of concrete with the limestone aggregate is investigated. Results are shown as follows:(1) According to the investigation of the past experiments, frost durability of concrete was not explained satisfactory by the basic property of coarse aggreegate.(2) According to the test results of the basic property test of the limestone coarse aggregate, the limestone is characterized by low water absorption, high specific gravity, low thermal coefficient and high content of stone power.(3) Differences of the thermal coefficient between the coarse aggregate and mortar cause thermal stress, and the low thermal coefficients of limestone cause large thermal stress. It is thought that the thermal stress affects frost deterioration of concrete.(4) For concrete, an existence of stone powder has effects of reducing air content and improving frost durability.(5) Freezing and thawing tests varied volume and the surface area of the coarse aggregate was conducted. It is thought that the effect of the thermal stress magnitude on frost durabllity of concrete is small. When the number of the coarse aggregate becomes large, frost durability of concrete becomes small. It is thought that number of cracks affect frost durability of concrete becomes small. It is thought that number of cracks affect frost durability of concrete.

尽管石灰石具有吸水率低、比重高的特点，但据说采用石灰石粗骨料的混凝土的抗冻耐久性低于采用优质粗骨料的混凝土。本文对石灰石骨料混凝土的抗冻耐久性进行了研究。结果如下：(1)根据以往的试验调查，混凝土的抗冻耐久性不能用粗骨料的基本性能来很好地解释。(2)根据石灰石粗骨料基本性能试验的结果，石灰石具有吸水率低、比重高、导热系数低、石粉含量高的特点。(3)粗骨料之间导热系数的差异。骨料和砂浆产生热应力，而石灰石的热系数低，产生较大的热应力。认为热应力影响混凝土的冻坏。(4)对于混凝土来说，石粉的存在具有降低空气含量、提高抗冻性能的作用。(5)对粗骨料进行不同体积和表面积的冻融试验。认为热应力大小对混凝土冻耐久性的影响较小。当粗骨料的数量变多时，混凝土的抗冻耐久性变小。认为影响混凝土抗冻耐久性的裂缝数量变少。据认为裂缝的数量影响混凝土的抗冻耐久性。