A polyurethane waterproofing membrane is made through the process of applying liquid polyurethane on substrate and then being cured on site. Therefore, the control of thickness of a membrane is the most important matter of concern in construction management. As a membrane was made by the work of a workman using tools such as a trowel or a squeegee, the shape and size of application area of roof floor par a worker is considered to affect the thickness of a membrane.

 This study is composed of the two works as follows, the experiment to know the effect of division of area before application and the one to make clear the suitable shape and size of area for a workman. In the first experiment, polyurethane material was applied on the exactly controlled area (4.0m×2.0m in size) and the not controlled area in a roof floor of an actual building. An observation during the work and a measurement of thickness of the membranes after cured revealed that the application work is consisted of the two steps of work such as pouring material on the substrate and then spreading it and indicating the shape and size of an area strictly before application is quite effective to make a membrane of enough thickness. In the second experiment, the effect of the shape and size of application area was furthermore discussed. As for pouring work, polyurethane material was flowed down from a small container in the areas of three levels of length such as 9.0m, 5.15m and 3.6m (0.8m, 1.4m and 2.0m long respectively) and then the weights of the material, cut into 10 pieces in length, were measured after completely curing. It was made clear the dispersion of weight was increased according to the increase of the length of an area.

 As for spreading work, the area of three levels of width such as 0.8m, 1.4m and 2.0m (9.0m, 5.15m and 3.6m wide respectively) were prepared and the polyurethane material placed in the areas was spread by two kinds of tools, a trowel and a squeegee. And then distribution of thickness of cured membranes and working hours through the work were measured. According as the application width became wider, the dispersion of thickness of membranes noticeably increased but working hours slightly decreased for trowel application. For squeegee application, not so much change was observed in dispersion but working hours was increased.

 By the above studies, the following results were obtained.

 (1) Dividing the roof floor into suitable shape and size of an area before application is effective for making a membrane of even and enough thickness.

 (2) For pouring work, the length of application an area influences on thickness of a membrane.

 (3) For spreading work, width of an application area also influences on working hours as well as on thickness of a membrane.

 (4) Three factors such as length and width of an area and working hours should be considered to decide a suitable application area.

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Abrasion induced by caster wheel traffic on concrete floors treated with surface reinforcing materials was investigated. The effects of concrete finishing, curing conditions, and the age of the surface reinforcing materials on abrasion resistance were evaluated.

The results demonstrate that proper curing after concrete placement is essential for enhancing the abrasion resistance of surface reinforcing materials against caster wheel traffic. Additionally, it was found that a specific curing period is required for the surface reinforcing materials to achieve their full abrasion-resistant capabilities.

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In this study, on site, the moisture conditions of concrete slab for targeting poured at different times were determined using humidity test paper and capacitive moisture meter until finishing floor covering. As a result, color chart value showed the same variation as that of temperature and humidity, indicating the possibility of being easily affected by the measurement environment. Moisture meter reading decreased with the lapse of lumber age, suggesting that it is not easily affected by the measurement environment.

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The thickness of fluid-applied polyurethane membrane is mainly affected by the viscosity and application tools. Then, the four levels of viscosity were prepared by changing the adding ratio of diluent from 0 to 10%. Polyurethane membranes were applied on substrate by various trowels and paint rollers. After curing the membrane, thickness was measured at 50mm intervals for all areas of the membrane. Based on the experimental results, the proper combination of diluent ratio and application tool for making a good membrane of having sufficient thickness was proposed.

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Buildings should be constructed under suitable execution circumstances according to users’ requirement quality. From this concept, actual construction experiment of concrete slab was carried out. When quality grades of flatness were shown, the finishing worker replied execution circumstances to achieve them. Most of differences were ways of screeding. After approving by the construct superviser, slabs were constructed under these circumstances. Then they almost became slabs of demanded quality. But when the high quality was required, the grade was not achieved partly.

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本報は，中泊くにうみウインドファームにおける傾斜を有する形状のフーチングの施工において，寒冷期に凝結促進用混和材を用いたコンクリートの適用結果について報告するものである。凝結の促進およびブリーディングの低減効果によって傾斜部の打込み・仕上げ面の品質が向上すること，さらに，仕上げの作業着手時間，終了時間を大幅に早めることができ，施工管理の職員やコンクリートの施工関係の作業者の負担を大幅に軽減することを示した。

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The water absorbency of the concrete slab surface is a big factor for defective adhesion of several finishing materials. We will propose "wet filter paper method", a handy method for measuring the water absorbency.
In this method, a filter paper that is wet in advance with a fixed amount of water is contacted closely with the slab surface. Then, the decrease in wet paper mass is obtained. Initial amount of water, duration of the measurement, and some other conditions were defined experimentally, and accuracy was also verified. In addition, it was clarified that the filter mass reduction corresponds to the water penetration depth.

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In this paper, two experiments were conducted to clarify the influence of coating amount of polymer cement paste on uniformity of thickness after hardening, adhesiveness, and watertightness. The followings are concluded from the test results. Uniformity of thickness after hardening is improved on vertical parts with a smaller coating amount. For Adhesiveness, a large coating amount on vertical parts is likely to cause adhesion defects. Regarding watertightness, a large coating amount is likely to cause moisture movement at the interface between hardened paste and waterproofing sheet above it. They are improved by reducing the coating amount of polymer cement paste.

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郡川橋りょう工事は，河川改修事業に伴う既設橋りょうの架替工事であり，明治期に築造された5径間の鋼製桁橋をPC2径間連続下路桁に架け替える工事である。下路桁は，主ケーブルシース周りや横締めPC定着部の箱抜き周りへのコンクリートの充填不良や締固め不足などの不具合の発生リスクが高い。本工事では，施工会社に蓄積された様々な経験知を活用してコンクリート工事の施工計画を立案した。そして，計画の妥当性を確認するために試験施工を行って新たな経験知の蓄積・反映と更なる改善を重ねながら施工を進め，本橋の品質確保に努めた。

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Investigate the influence of changes in unit volume of water and sand-total aggregate ratio in high-strength concrete, results of pumping experiments by actual concrete pumps, finishing experiments by plaster craftsman and compressive strength tests by imitated concrete column are described.

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In this paper, two experiments were conducted to clarify the influence of polymer cement paste mix proportion on in-plane permeability resistance, adhesiveness and watertightness. The followings are concluded from the test results. If the quality of the underlying concrete is poor, fracture at the interface between substrate and hardened paste is likely to occur. If the paste is a softer mix proportion, adhesive failure and moisture migration are more likely to occur due to the formation of a fragile layer, presumably caused by bleeding. These problems can be improved by mixing a standard amount of polymer in this waterproofing system.

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The method for construction management for construction woks of polyurethane waterproofing membrane being improved in repair work site was described in this research. The effectiveness of the method was confirmed by being applied to subsequent repair works. To check the quality of repair work of polyurethane waterproofing membrane, thickness of membrane was verified. The aging condition was also inspected for ensuring aged membrane.

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Concrete is subject to cracks because of its high hardening-and-drying-shrinkage, and also of its low tensile strength and extensibility. It is owing to that defect in concrete that the roof-deck cannot be perfectly free from cracks. Various plans have so far been devised and carried into effect to cope with these drawbacks in concrete of generating cracks and propagating them, so as to secure for the roof-deck complete waterproof virtue. Most of these waterproof contrivances consist of covering the roof-deck with layers of films which we may call roofing membranes.
Of the roofing membranes then it is required as of paramount importance in the roofing system that they will on no account rupture, whatever may be the width of the cracks that occur in the concrete of the roof-deck. Special attention must, therefore, be paid to adjustment of such physical properties of the roofing membranes as its tensile strength, its maximum elongation, its modulus of elasticity and its resilience, of its thickness and of its adhesive strength to the roof-deck.
In this paper the resistance of the roofing membranes to the cracks in the concrete of the roof-deck is theoretically and experimentally discussed. As the result the condition that effectively protects the roofing membranes from rupture in spite of the cracks in the concrete of the roof-deck is proposed as follows:
τ_s≤4d/lR_s
where
τ_s: Shear-adhesive strength of the roofing membrane material to the concrete of the roof-deck in kg/cm²
d: The thickness of the roofing membrane in cm
R_s: The limit of resilience of the roofing membrane in kg/cm²
l: The crack width in the concrete of the roof-deck in cm.
This equation has also been applied to polymer roofing membranes which were made up of synthetic polymeric roofing sheets and polyurethane fluid-applied roofings, and their resistance to cracks in the concrete of the roof-deck has been tested.

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This technique worked on development of technology to prevent the cracking occurs also in refurbishment layer of cracking the top by aging, in the case of adopting the pin net method on the outer wall that occurred through cracks. By typing an anchor pin in through cracks part, it was tried to reduce the cracking of the repair layer because of controlling the crack behavior of concrete. Experiment was performed from strength and energy absorption of the specification by the bending test of a small specimen. As a result, to type the T-forked anchor pin into the through cracks section revealed that can be expected to improve the adhesive strength at the crack and the flexibility to warping of the wall.

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