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Studies on Compaction Mechanism and Judging Compaction Degree of Extremely Stiff Consistency Concrete

特硬稠度混凝土压实机理及压实度判别研究

基本信息

批准号：
63550347
负责人：
TOKUDA Hiroshi
金额：
$ 1.41万
依托单位：
Akita University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1989
项目状态：
已结题

项目摘要

The extremely stiff consistency and lean six concrete was placed into prismatic specimen moulds and compacted by surface vibrator. The compaction process was observed through a transparent side panel of the mould and the cement paste pressure was measured simultaneously by pore water pressure gauge embedded in the bottom part. On the other hand, unit contents of internal constituent materials and compressive strength in each position in the vertical direction were measured. The conclusions are as follows.(1) Cement paste moved downward at early compaction stage, subsequently the moving direction changed to upward and spaces between aggregate particles were filled up thoroughly by cement paste.(2) The pressure in cement paste increased gradually with compaction periods and reached the maximum value just at the time the spaces were filled up, and then turned to decrease.(3) The air content in each position decreased with increase in compaction periods, and the content in lower position was about 1% higher than that in upper position. Water cement ratio in lower position was higher than that in upper position up to certain compaction periods, and after these periods the reversed trend could be observed.(4) The periods taking to reach the maximum pressure were nearly equal to those corresponding to the maximum compressive strength. Therefore, compaction degree could be judged by measuring the pressure. Still more, the gauge attached to the end of steel pipe was embedded in the large scaled specimen, and after compaction effort the pipe could be pulled out easily and be reused.

将非常坚硬、坚硬和稀薄的六号混凝土放入棱柱形试件模具中，用表面振动器进行压实。通过模具的透明侧板观察压实过程，并通过嵌入底部的孔压计同时测量水泥浆体压力。另一方面，测量了内部组成材料的单位含量和垂直方向上各位置的抗压强度。结论如下：(1)压实初期水泥浆体向下移动，随后向上移动，骨料颗粒之间的空隙被水泥浆体完全填满。(2)水泥浆体内的压力随压实周期的延长而逐渐增大，在空隙被填满时达到最大值，然后逐渐变小。(3)各个位置的含气量随压实周期的增加而降低，下部的含气量比上部的高出约1%。在一定的压实周期之前，下部的水灰比高于上部的水灰比，在此之后可以观察到相反的趋势。(4)达到最大压力所需的时间与最大抗压强度所对应的时间基本相同。因此，可以通过测量压实度来判断压实度。此外，连接在钢管末端的量规被嵌入到大尺寸试件中，经过压实努力后，钢管可以很容易地拔出并重复使用。