• Journal of the Korean Society of Safety
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• v.14 no.2
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• pp.122-126
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• 1999

In this study, using the temperature history analysis, the influences of the conductive values of wooden form, which are specified by Korean Standard for Concrete and ACI Practice Manual for Concrete, on the temperature history were examined. And, the calculated temperature history is compared with the measured temperature history. In the examination for the influences of the conductive values of wooden form, the value recommended by the Korean Standard can more closely predict the themperature history at the points which the variation of the boundary condition should be considered.

• Corrosion Science and Technology
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• v.3 no.3
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• pp.127-130
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• 2004

Throughout the world, corrosion of rebar in concrete is a main form for concrete building destruction. The chloride is prime criminal. This paper presents the harm of chloride corrosion in China, the effect of chloride corrosion on the durability of concrete buildings and protection strategies for rebar corrosion.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.639-642
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• 1999

Pullout test known as Lok test among the test methods to evaluate concrete strength strength is a test method which is used to decide the form removal time by assessing the early strength of concrete in a new construction, or to control the quality of newly placed concrete. This method has inconvenience to place inserts on the form work in advance, however, the placing work is quite simple and it has advantage that the strength can be measured at field as long as the inserts are placed. In this study, the first step is to investigate the properties of test method itself, by performing the laboratory test which covers deviation of the method and factors affecting the results, etc. The second step is to correlate the result with cylinder strength and other NDT methods such as rebound hammer, ultrasonic method, etc. And that, the results are compared with foreign results to find the differences between the two. In this research, new factors such as moisture content, area of aggregate failure cross section and area of aggregate separation cross section, etc as well as wate-cement ratio and age are investigated.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.317-322
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• 1995

This study is to examine the usefulness in using precast girder-infilled steel tube column in reinforced concrete structures through the analysis of the test results, in order to develope the new composite structural system using precast girder-Infilled steel tube column, The variables of specimen are strength of concrete, the numble of hoops, the form of beam-column The variables of specimen are strength of concrete, the number of hoops, the form of beam-column joints. By raising strength of concrete and incresing number of hoops in beam-column joint, it becomes clear to take similar structure capacity to monolithic structures.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.10a
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• pp.295-300
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• 1996

The design of formwork system for vertical form faces is controlled by pressures predicted to act against the formwork by fresh concrete. An overestimation of pressure results in heavy, and ex-pensive formwork. An underestimation results in malformed structure, of in some cases, it causes the failure of the formwork. This study is a preliminary step in determination lateral pressures with High folwable concrete. To estimate lateral formwork pressures, we measured tensile strain of formtie in the movable part of the form. From the experimental results maximum lateral pressure and the location at which maximum pressures occurs, were determined. The experimental results are compared with the results predicted by the Gardner & Qureshi's proposed equation and the accepted Korean Standard Specification for concrete and ACI equation.

• Computers and Concrete
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• v.6 no.1
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• pp.79-93
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• 2009

In the present paper, a methodology has been presented for the reliability assessment of concrete barriers that lie at a certain depth in the soil, and a missile (a rigid projectile) impacts the top of the soil cover normally, and subsequently after penetrating the soil cover completely it hits the barrier with certain striking velocity. For this purpose, using expressions available in the literature, striking velocity of missile at any depth of soil has been derived and then expressions for the depths of penetration in crater and tunnel region of concrete barrier have been deduced. These depths of penetration have been employed for the derivation of limit state functions. Using the derived limit state functions reliability assessment of underground concrete barrier has then been carried out through First Order Reliability Method (FORM). To study the influence of various random variables on barrier reliability, sensitivity analysis has also been carried out. In addition, a number of parametric studies is conducted to obtain the results of practical interest.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.203-204
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• 2014

Unlike other members, beams have various cross-sections and they have an important role of delivering the load of slabs. A beam form neighbors the columns and slabs, which makes it difficult to be installed. In a conventional way to exclusively use the form after concrete pouring, the form and a support should be both removed. Then, the support should reinstalled to sustain the stripping time of form, resulting in a structural issue. To solve such structural problem, the study proposes SMART beam form that uses filler panels and supports for filler. The floor filler panels and supports for filler are not removed after concrete curing, to conform to the stripping time of supports. Thus, any structural problem such as cracks and reduction of compressive strength owing to the gap of load bearing capacity can be prevented. The study results will be used as cases for studies on productivity analyses.

• Journal of the Korea Institute of Building Construction
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• v.1 no.1
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• pp.143-150
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• 2001

Permanent-Form is one of system forms for reducing human labor, work costs, oscillation, noise, construction wastes and so on. Permanent-Form is made from precast method in facilities, and carried in construction site to assemble with no demolding. The biggest expense to produce permanent-Form is about manufacturing mold. This papers about structural efficiency evaluation, construction efficiency test. The result of this study is below. (1) In the compressive strength test of column. Fly ash specimen and polymer specimen's strength developed as each 8%, 14% to comparison with standard specimen. The reason of this result from form section area increase and form's reinforcing bar (2) The Degree of column crack in permanent form is lower than another one's The glass fiber's fiber reinforcement effect brings like this. (3) In the flexural load test of beam, the early crack load and maximum load of permanent form use specimen showed 20% higher than standard specimen's. (4) In field application experiment, an constructional error is satisfied with the allowable margin of error, $\pm$5mm (5) When the concrete is placed into the form inside, The transformation degree of permanent form is lower than plywood form's. (6) The concrete packing ability of permanent form is satisfactory. (7) The bonding strength of permanent form shows enough strength - 6kgf/$\textrm{cm}^2$.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.05a
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• pp.153-154
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• 2019

This study is a mock-up experiment prior to field application of insulated gang form. In order to investigate concrete Heating cost in winter, pre-comparison was made before application.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.129-130
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• 2020

This paper attempted to examine the characteristics of heat of hydration and calorific value of concrete according to the formwork material in Hot weather environment. As a result of the experiment, it was found that there were no problems such as temperature cracking and delay in hydration reaction when a synthetic resin form was used.