Gamil Yaser, Cwirzen Andrzej, Nilimaa Jonny, Emborg Mats
Building Materials, Department of Civil, Environmental and Natural Resources Engineering, Lulea University of Technology, 97187 Luleå, Sweden.
Materials (Basel). 2023 Jan 12;16(2):759. doi: 10.3390/ma16020759.
Despite the advantageous benefits offered by self-compacting concrete, its uses are still limited due to the high pressure exerted on the formwork. Different parameters, such as those related to concrete mix design, the properties of newly poured concrete, and placement method, have an impact on form pressure. The question remains unanswered on the degree of the impact for each parameter. Therefore, this study aims to study the level of impact of these parameters, including slump flow, T500 time, fresh concrete density, air content, static yield stress, concrete setting time, and concrete temperature. To mimic the casting scenario, 2 m columns were cast at various casting rates and a laboratory setup was developed. A pressure system that can wirelessly and continuously record pressure was used to monitor the pressure. Each parameter's impact on the level of pressure was examined separately. Casting rate and slump flow were shown to have a greater influence on pressure. The results also demonstrated that, while higher thixotropy causes form pressure to rapidly decrease, a high casting rate and high slump flow lead to high pressure. This study suggests that more thorough analysis should be conducted of additional factors that may have an impact, such as the placement method, which was not included in this publication.
尽管自密实混凝土具有诸多优势，但由于其对模板施加的压力较大，其应用仍然有限。不同参数，如与混凝土配合比设计、新浇筑混凝土性能以及浇筑方法相关的参数，都会对模板压力产生影响。每个参数的影响程度问题仍未得到解答。因此，本研究旨在研究这些参数的影响程度，包括坍落扩展度、T500时间、新拌混凝土密度、含气量、静态屈服应力、混凝土凝结时间和混凝土温度。为模拟浇筑场景，以不同浇筑速度浇筑2米高的柱体，并搭建了实验室装置。使用一个能够无线连续记录压力的压力系统来监测压力。分别研究了每个参数对压力水平的影响。结果表明，浇筑速度和坍落扩展度对压力的影响更大。结果还表明，虽然较高的触变性会使模板压力迅速降低，但高浇筑速度和高坍落扩展度会导致压力升高。本研究表明，对于可能产生影响的其他因素，如浇筑方法（本出版物未涵盖），应进行更深入的分析。
