著者

荒巻 卓見 中田 善久 大塚 秀三 宮田 敦典

出版者

一般社団法人 日本建築学会

雑誌

日本建築学会技術報告集 (ISSN:13419463)

巻号頁・発行日

vol.27, no.65, pp.58-63, 2021-02-20 (Released:2021-02-20)

参考文献数

11

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The purpose of study was to clarify the quality of plywood for concrete formwork with reuse of forms and the finish of concrete surface using reused plywood. In this study, an experiment on influence of reuse (up to 4 times) of plywood for conventional formwork at building construction site was carried out. Regarding the influence of reuse on the quality of plywood, bending strength, bending Young’s modulus, and surface roughness were investigated. In addition, the influence of reused plywood on gloss, color unevenness, and water absorption of the concrete surface was investigated. Moreover, in order to confirm the influence of reuse of plywood at construction site, the results of this experiment at building construction site were compared with the results of laboratory experiment conducted so far.

著者

荒巻 卓見 中田 善久 大塚 秀三 手島 基 宮田 敦典

出版者

一般社団法人 日本建築学会

雑誌

日本建築学会技術報告集 (ISSN:13419463)

巻号頁・発行日

vol.20, no.44, pp.13-18, 2014-02-20 (Released:2014-02-20)

参考文献数

14

被引用文献数

2 3

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This study purposed for prehension about the actual situation of work from the viewpoint of formwork contractors. In this paper, we conducted a questionnaire survey about concrete form plywood, strength and rigidity of form, and formwork based on the experience of formwork carpenters in Kanto region. As a result, it elucidated the actual situation of work, concrete form plywood, strength and rigidity of form, and formwork in the construction site.

著者

宮田 敦典 中田 善久 大塚 秀三

出版者

日本建築学会

雑誌

日本建築学会構造系論文集 (ISSN:13404202)

巻号頁・発行日

vol.83, no.751, pp.1217-1227, 2018 (Released:2018-09-30)

参考文献数

38

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It is significant to accurately grasp the pressure loss per unit length of pipeline in calculating total pressure of pipeline. The standard value of pressure loss per unit length of pipeline is shown in recommendation for practice of placing concrete by pumping methods. The standard value of pressure loss per unit length of pipeline were obtained from pumping experiment conducted around 1970. But, mix-proportion and concrete materials has changed compared to the 1970s. Especially, design strength has risen compared to the 1970s, and high-range AE water reducing agent was developed and has spread. Therefore, concrete that has been used recently can't apply the standard value of pressure loss per unit length of pipeline. So this study aimed to reveal influence of mix-proportions on the pressure loss per unit length of pipeline by literature survey and pumping experiment. In the first, we studied the influence of water-cement ratio on the pressure loss per unit length of pipeline. Pressure loss per unit length of a pipe tended to be roughly proportional to the square of cement-water ratio. Next, we examined pressure loss per unit length of pipeline for each slump of concrete that more than W/C 45%, and we examined pressure loss per unit length of pipeline for each unit water content of concrete that less than or equal to W/C 45%. As a result, pressure loss per unit length of pipeline tended to increase when slump decrease and unit water content is low. And we derived the relational expression between pressure loss per unit length of pipeline and true output capacity. In additions, this paper proposed standard value of pressure loss per unit length of pipeline of concrete that more than W/C 45% on the basis of literature survey results. Finally, we confirmed the validity of the relational equation obtained from literature survey by pumping experiment. This paper shows a result of pressure loss per unit length of pipeline of concrete with normal portland cement. Therefore, we should does experiment of test pumping with reference to result of this paper when we use concrete with cement and materials other than normal portland cement.