• International Journal of Concrete Structures and Materials
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• v.10 no.3
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• pp.373-381
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• 2016

As part of this study, has been developed a numerical method which allows to establish abacuses connecting the normal force with bending moment for a circular section and therefore to predict the rupture of this type of section. This may be for reinforced concrete (traditional steel) or concrete reinforced with steel fibers. The numerical simulation was performed in nonlinear elasticity up to exhaustion of the bearing capacity of the section. The rupture modes considered occur by plasticization of the steel or rupture of the concrete (under compressive stresses or tensile stresses). Regarding the fiber-reinforced concrete, the rupture occurs, usually, by tearing of the fibers. The behavior laws of the different materials (concrete and steel) correspond to the real behavior. The influence of several parameters was investigated, namely; diameter of the section, concrete strength, type of steel, percentage of reinforcement and contribution of concrete in tension between two successive cracks of bending. A comparison was made with the behavior of a section considering the conventional diagrams of materials; provided by the BAEL rules. A second comparative study was performed for fibers reinforced section.

• Magazine of the Korea Concrete Institute
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• v.7 no.5
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• pp.23-32
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• 1995

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.565-573
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• 2009

Even in case of new materials, materials that are not only harmless for the current global environment but also have high-performance and high-function are sought-after in consideration of the global environmental problems. Moreover, in construction areas where a large amount of cement and concrete are used, the establishment of the recycling technology or transformation into resources and energy materials are being put in place. And also, in a situation where the slow and relaxed city and rural life have a high priority, the need for cement and concrete as environmentally friendly new materials that best suit the emotions in human beings is on the rise and a new way to make good use of cement and concrete as new materials in construction technology should be sought. The recently introduced functional and environmentally friendly concrete is aimed at enhancing health through the adjustments of the body biorhythm using far-infrared. Minerals that contain a great amount of the elements with the frequent occurrence of the infrared among earth minerals and concrete are mixed to use structures or finishing materials, which will tackle the issues of smells, mold and corrosion.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.317-320
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• 2006

In this paper, in order to inspect effect of marketed repair materials, it inspected first the repair material through laboratory work by repair method. After we carry out laboratory work and choice the construction with ongoing deterioration to inspect performance of repair materials, we apply the repair materials there. This results will be make use of reference whenever selection of repair materials and repair method. Also which will be used basic data for repair construction code.

• School Mathematics
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• v.18 no.1
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• pp.159-173
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• 2016

In real educational field, there are cases that concrete problematic situations are introduced after abstract concepts are taught on the contrary to process that abstract from concrete contexts. In other words, there are cases that abstract knowledge has to be concreted. Freudenthal expresses this situation to antidogmatical inversion and indicates negative opinion. However, it is open to doubt that every class situation can proceed to abstract that begins from concrete situations or concrete materials. This study has done a comparative analysis in difference of mathematical thinking between a process that builds abstract context after being abstracted from concrete materials and that concretes abstract concepts to concrete situations and attempts to examine educational implication. For this, this study analyzed the mathematical thinking in the abstract process of concrete materials by manipulating AiC analysis tools. Based on the AiC analysis tools, this study analyzed mathematical thinking in the concrete process of abstract concept by using the way this researcher came up with. This study results that these two processes have opposite learning flow each other and significant mathematical thinking can be induced from concrete process of abstract knowledge as well as abstraction of concrete materials.

• Computers and Concrete
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• v.19 no.5
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• pp.515-526
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• 2017

Recent trend is to use the lightweight concrete in the construction industry because it has several advantages over normal weight concrete. The Lightweight concrete can be produced from the industrial waste materials. In South East Asian region, researchers are very keen to use the waste materials such as oil palm shell (OPS) and palm oil clinker (POC) from the palm oil producing industries. Extensive research has been done on lightweight concrete using OPS or POC over the last three decades. In this paper the aggregate properties of OPS and POC are plotted in conjunction with mechanical and structural behavior of OPS concrete (OPSC) and POC concrete (POCC). Recent investigation on the use of crushed OPS shows that OPSC can be produced to medium and high strength concrete. The density of OPSC and POCC is around 20-25% lower than normal weight concrete. Generally, mechanical properties of OPSC and POCC are comparable with other types of lightweight aggregate concrete. It can be concluded from the previous study that OPSC and POCC have the noteworthy potential as a structural lightweight concrete.

• Journal of the Korea Concrete Institute
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• v.24 no.4
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• pp.361-368
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• 2012

Required performance for repair materials are strength, ductility, durability and bonding with the substrate concrete. Various kinds of fiber-reinforced cement composites (FRCCs) have been developed and used as repair materials. Strain-hardening cement based composites (SHCC) is one of the effective repair materials that can be used to improve crack-damage tolerance of reinforced concrete (RC) structures. SHCC is a superior FRCC that has multiple cracking characteristic and pseudo strain-hardening behavior. The expansive admixture, which can be used to reduce shrinkage in SHCC materials with less workability by controlling interfacial bonding performance between SHCC and substrate concrete. For the application of SHCC as a repair material to RC structures, this study investigates the flexural performance of expansive SHCC-layered concrete beam. Test variables include the replacement levels of expansive admixture (0 and 10%), repair thickness (30 and 40 mm), and compressive strength of SHCC (30, 70 and 100 MPa). Four point bending tests on concrete beams strengthened with SHCCs were carried out to evaluate the contribution of SHCC on the flexural capacity. The result suggested that expansive SHCC materials can be used for repairing and strengthening of concrete infrastructures.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.04a
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• pp.212-218
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• 1995

This study experimentally evaluated the performance of damaged section which was repaired using polymer materials in reinforced flexural flexural members Six different materials, two types of polymer, two types of polymer-cement and two types of cement, were used by means of injection method on prepacked concrete and spray mortar patching method. As results, the repair works could be done easily and surfaces of the repaired section were smooth.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.523-526
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• 2003

Functions of the building structures are recently expended, because the structures are getting larger and people's indoor staying times are getting longer. Therefore, various functional materials such as yellow mud, carbon soot, and jade are widely used. But functions of those materials have not permanent and continued an effect. Specially, the development of construction materials containing anti-insect is highly important to delight the environment of residence. This research try to examine to develop the mortar and concrete which contain microcapsules with long-term effect of anti-insect.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.350-354
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• 1995

Deteriorated concrete components are repaired using various repair materials for preventing functional deficiencies. However, the durability performance of these materials is not very well investigate. This study aims to examine the dynamic behavior of R/C beams repaired by Polymer, Polymer-Cement and Cemtitious material through dynamic test. Totally 18repaired R/C beams were tested, and the results from dynamic test of beams repaired with various materials were compared.