• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.175-176
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• 2020

As the concrete pouring work relies on manual work, there is a lot of room for automated equipment development. In this study, as a basic study on the development of an automated system for pouring concrete, the trend of patent applications by year, country and detailed technology was investigated. Related technologies were classified into screed automation, CPB automation, and concrete pouring integrated system to analyze patent application trends. As a result, since 1999, patent applications have been steadily in progress, repeating increases and decreases in Japan, Korea, the United States, and Europe. In addition, the growth stage of the market is in the early stages of maturity, and patent applications for related technologies are expected to continue. In the future, based on the patent application trend analyzed in this study, the development direction of the automated concrete pouring system will be reviewed and the redundancy of similar technologies will be reviewed.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.197-198
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• 2014

The concrete work of bridge decks is performed in a high place, which may reduce safety and productivity. In addition, the conventional method for deck forms require a great deal of manpower, and a form (sheathing) board is damaged when removed after curing. As a result, the concrete deck work of bridge construction becomes the cause of delayed construction and increased cost. To solve these problems, SMART form, a system form, is developed. SMART form is a temporary device for easier installation and removal, by mounting it to the lower flange of a bridge girder and using a mechanical behavior of the form system for deck concrete pouring. For stable installation and removal of the developed SMART form, geometric behaviors should be analyzed to prove its validity. Furthermore, the validity of geometric behaviors when the SMART form size is altered in response to the various arrangement of bridge girders should be proved. Thus, the study is intended to analyze the geometric validity of the form system for bridge deck concrete pouring. The structural stability of the form system for bridge deck concrete pouring can be secured, which will be applied in the field.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.82-83
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• 2017

The samll-medium sized cities do not have enough infrastructure for the construction work, especially in terms of concrete supply. This research surveyed the capacity of remicon companies in Gunsan related with production and delivery. Their production capacity is bigger than the daily quantity required, however the delivery capacity is not enough to supply the daily quantity required and it is inevitable to use the several remicon using different admixture. It might cause the harm to the structure. This research studied the way to remove the quality risk when using different admixture at the same time.

• Korean Journal of Construction Engineering and Management
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• v.20 no.1
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• pp.133-140
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• 2019

The concrete mix should be designed and produced to reflect the specific site conditions during concrete placement. That is, the concrete mix design should be planned considering temperatures, work environments, pouring methods, etc. The objective of this research is to understand the external factors of curing temperature and delay time that influence concrete strengths during pouring work, and provide concrete mix design that can be most robust to the effects of external factors. The Taguchi's robust method is used in preparing the concrete mix design to achieve the research objective. In a case study, an indoor concrete test was performed to find the optimal combination of concrete mixes with external factors of curing temperature and delay time. Concrete test cylinders were made to test concrete strengths given different external factors. The study results showed that the optimal performance of concrete strength can be achieved by applying the robust method when preparing a concrete mix design.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.600-601
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• 2015

Both the importance and process of estimating Nuclear-power plant construction time and cost have increased in significance as energy user costs themselves have become more significant. In estimating construction time, few parameters are more significant than work item production rates and factors significantly affecting the rates. A standardized data collection tool was used to acquire a total of 401 data points from a S Nuclear-power plant project, for selected critical works: form-work, rebar-work, and concrete-pouring. With the data, several hypothesized drivers of the man-hour production rates and crew-day production rates were also analyzed. Findings from this study will enable industry professionals to enhance accuracy of time and cost estimation for nuclear power plant construction.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.42-43
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• 2014

Few studies on crew productivity has been conducted, although the data is significant for time and cost estimation. Crew productivity data was collected for over 9 months from a nuclear power plant and analysed in order to identify factors driving the productivity. It was revealed that the crew productivity of form work, rebar work and concrete pouring work was 45.64(㎡/crew·day), 2.93(t/crew·day), 110.25(㎡/crew·day) on average respectively. Moreover, 'nightwork', 'No. of workers per crew' and 'total work amount' were identified as drivers.

• Journal of the Korea Concrete Institute
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• v.12 no.3
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• pp.77-85
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• 2000

Various concretes are used for construction works depending on the types of structure, building element and method of construction. An internal vibration work is one of the important processes for adequately pouring various concrete into a certain form. This study was undertaken to find out the effects of internal vibration on flowability of fresh concrete by concrete flow test under eight conditions of vibration. Presumable equation models also were created to show all vibration effects without regard to kinds of concrete. As the results of this study, the degree of vibration effects were varied according to the properties of concrete. Acceleration amplitude of vibration that applied to fresh concrete was effective value of the properties of vibration in a viewpoint of flowability. Moreover, This research presents the presumed equation models including variables created by acceleration amplitude and measuring value of vibrated concrete flow test. These models are presumable methods of vibration effects regardless of kinds of concrete.

• Structural Engineering and Mechanics
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• v.45 no.6
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• pp.837-851
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• 2013

In construction industry, strength is a primary criterion in selecting a concrete for a particular application. The concrete used for construction gains strength over a long period of time after pouring the concrete. The characteristic strength of concrete is defined as the compressive strength of a sample that has been aged for 28 days. Neither waiting for 28 days for such a test would serve the rapidity of construction, nor would neglecting it serve the quality control process on concrete in large construction sites. Therefore, rapid and reliable prediction of the strength of concrete would be of great significance. On this backdrop, the method is proposed to establish a predictive relationship between properties and proportions of ingredients of concrete, compaction factor, weight of concrete cubes and strength of concrete whereby the strength of concrete can be predicted at early age. Multiple regression analysis was carried out for predicting the compressive strength of concrete containing Portland Pozolana cement using statistical analysis for the concrete data obtained from the experimental work done in this study. The multiple linear regression models yielded fairly good correlation coefficient for the prediction of compressive strength for 7, 28 and 40 days curing. The results indicate that the proposed regression models are effectively capable of evaluating the compressive strength of the concrete containing Portaland Pozolana Cement. The derived formulas are very simple, straightforward and provide an effective analysis tool accessible to practicing engineers.

• Journal of the Korea Institute of Building Construction
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• v.12 no.3
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• pp.291-298
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• 2012

For cold weather concreting, frost damage at early age is generated in the concrete, and problems such as delaying of setting and hardening and lowering of strength manifestation emerge due to the low outside air temperature at the early stage of pouring, making the selection of an effective curing method critically important. Unfortunately, the tent sheet currently used as the curing film for heating insulation at work sites, not only has the problems of inferior permeability and extremely deteriorated airtightness, but a phenomenon of continuous fracturing is also generated along the direction of fabric of the material itself, presenting difficult circumstances for maintaining adequate curing temperature. The aim of this study was to develop an improved bubble sheet type curing film for heating insulation of cold weather concrete by combining mesh-tarpaulin, which has excellent tension properties, with bubble sheet, which offers superior insulation performance. The analysis showed that the improved curing film in which BBS1 is stacked to MT was a suitable replacement for curing films currently in use, as it has better permeability, tension property, and insulation performance than the T type film used at work sites today.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.217-218
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• 2009

This experimental work is to verify the previously developed prediction model for self-consolidating concrete (SCC) formwork pressure. A new apparatus was devised to simulate formwork pressure in laboratory, and experiments were performed for one SCC mix. The predicted pressure with the calibrated parameters were compared with the pressure measured under continuous and discrete pouring. The calibrated parameters have a specific trend over loading time, and the calculated pressure accurately simulates the real pressure varying over time.