Segregation Characterisics of Fresh concrete

新拌混凝土的离析特性

• 批准号: 08455205
• 负责人: MACHIDA Atsuhiko
• 金额: $ 3.84万
• 依托单位: Saitama University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08455205/
• 关键词: Fresh Concrete; High-Fluidity Conc.; Bingham Constants; DEM Simulation; DEM Parameters; Funnel Test; Segregation; Blockade; ロ-ト流下試験; DEM; シミュレーション; ダッシュポット定数; バネの許容引張力

Dragging Ball Viscometer test, slump test, funnel test and T-shaped tube test were carried out on con- cretes of which mix propotions were changed widely, and these tests were simulated by DEM (distinct element method). The results can be summarized as follows.(1) Relations between Bingham constants and mix proportions were determined based on dragging ball viscometer tests, and relations between Bingham constants and DEM parameters were determined by DEM analysis. Equations to determine DEM parameters based on mix proportions were proposed using these results.(2) It was concluded from the results of DEM analysis on slump test, funnel test and T-shaped tube test using the DEM parameters determined as above that behavior of fresh concrete can be simulated almost satisfactorily, provided Bingham constans in the analysis are near to those in the experiments.(3) However, it was also found that applicable range of equations relating Bingham constants to DEM parameters is relatively narrow due to the deviations of analysis and that behaviors of fresh concrete can not be simulated beyond this range. Further studies are needed to set up more precise equations.(4) It was made clear qualitatively by DEM analysis where and how segregation of coarse aggregate and resulting blockade occur and propagete in funnel test and T-shaped tube test.

对配合比变化较大的混凝土进行了拉球粘度试验、坍落度试验、漏斗试验和T形管试验，并采用离散元法（DEM）进行了模拟。结果可归纳如下。(1)通过拖球粘度计试验确定了宾厄姆常数与配合比的关系，通过离散元分析确定了宾厄姆常数与离散元参数的关系。利用这些结果，提出了基于配合比的DEM参数确定方程。(2)用所确定的离散元参数对坍落度试验、漏斗试验和T形管试验进行离散元分析的结果表明，只要分析中的宾汉常数与试验中的宾汉常数接近，就可以很好地模拟新拌混凝土的性能。(3)但由于分析结果的偏差，Bingham常数与DEM参数之间的关系式适用范围较窄，超出此范围无法模拟新拌混凝土的力学性能。需要进一步的研究来建立更精确的方程。(4)通过离散元分析，定性地阐明了漏斗试验和T形管试验中粗集料离析及其堵塞的发生和发展的位置和方式。

项目成果

Chu Hongwei: "Simulation of Self Compactable Concrete Consistency Experimental Evaluation by Distinct Element Method" CANMET/ACI/JCI Fourth International Conference on Recent Advances in concrete Technology. 691-714 (1998)

褚红卫：《通过特征元法模拟自密实混凝土稠度实验评价》CANMET/ACI/JCI第四届混凝土技术最新进展国际会议。

小林秀徳: "個別要素法による高流動コンクリートの流動解析用パラメータに関する研究" 第21回コンクリート工学年次論文報告集. (発表予定).

小林英德：“使用离散元法进行高流动性混凝土流动分析参数的研究”第21届混凝土工程年度论文报告集（预定发表）。

Chu Hongwei: "Experimental Investigation and DEM Simulation of Filling Ca-pacity of Fresh Concret" Proceedings of JCI. Vol.18-1. 471-476 (1996)

褚宏伟：《新拌混凝土填充能力的实验研究与DEM模拟》JCI论文集。

Chu Hongwei: "Verification of Application of DEM to Fresh Concrete by Sphere Dragging Viscometer" 第20回コンクリート工学年次論文報告集. 19・1. 463-468 (1997)

褚宏伟：“球体拖动粘度计对DEM在新拌混凝土中的应用验证”第20届混凝土工程年会19・1（1997）。

Chu Hongwei: "Mumerical Simulation of Fluidity Behavior of Fresh Concrete by 2D Distinct Element Method" Proceedings of JCI symposium on Consistency and Workability of Fresh Concrete. 91-98 (1996)

褚宏伟：《用二维离散元法对新拌混凝土流动性行为进行数值模拟》JCI新拌混凝土稠度与和易性研讨会论文集。