Develpoment of Pumpability Testing Machine of Fresh Concrete
Grant-in-Aid for Developmental Scientific Research
|Allocation Type||Single-year Grants |
|Research Institution||University of Tokyo |
OKAMURA Hajime University of Tokyo, Porfessor, 工学部, 教授 (30010664)
HASHIMOTO Chikanori The Technological University of Nagaoka, Assistand Lecturer, 工学部, 助手 (10180829)
MAEKAWA Koichi University of Tokyo, Associate Professor, 工学部, 助教授 (80157122)
SHIMIZU Keiji The Technological University of Nagaoka, Procfessor, 工学部, 教授 (50143813)
|Project Period (FY)
1986 – 1987
Completed (Fiscal Year 1987)
|Budget Amount *help
¥7,100,000 (Direct Cost: ¥7,100,000)
Fiscal Year 1987: ¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 1986: ¥4,700,000 (Direct Cost: ¥4,700,000)
|Keywords||visualized test / fresh concrete / pipe flow / solid phase / liquid phase / taper potion / segregation / blocking / electrical resistance / two phase model / simulation / 管内閉塞 / 材料分離 / 可視化実験手法 / 粗骨材濃度 / 流動性 / 変動性|
This project was concerned with development of pumpability testing mochine of fresh concrete.
The results of this project in two years are given as follows.
(1) Establishment of vesualized testing method for modeled concrete in pipe flow
We developed modeled concrete, which consists of absorbent polymer as liquid phase and lightweight aggregates and coke as solid phase. Mix proportion of absorbent polymer was designed so that its fluidity was similar to that of actual mortar in fresh concrete. And the solid phase in liquid phase of pipe flow could be visualized to follow the motion of solid phase. Then with the use of video deck and A/D converter, the measuring system of particle motion in time domain was developed. From the results of this visualized test, we could clariify the deformation and blocking mechanism of flowing concrete in tapered pipe and segregation process in bifurcated potion.
(2) Development of electrical resistance measuring system for segregation of fresh concrete in pi
We developed the electrical resistance measuring system for actual fresh concrete to represent the volume ratio of aggregates in concrete indirectly. Then the wear out resistance of electrode was improved. From the site experimental results with the use of this measuring system, the evaluation method for segregation and critical blocking condition of flowing concrete was proposed. we applied for two patents on the above developments.
(3) Development of segregation model for solid-liquid flow of two phase material
Based on the information from the visualized test (1). two phase model of flowing concrete was developed and the simulation of segregation and blocking of fresh concrete in pipe flow was counducted. From this simulation, the following results were derived.
(a) Segregation, defined as the volume change of solid phase, is accelerated in the taper potion.
(b) High viscosity of liquid phase leads to the considerable high pressure in pipe and to the high segregation resistance, which results in the good fluidity of total material. Less
Report (2 results)
Research Products (17 results)