變形硬化型 高靭性시멘트複合材料의 製造 및 性能平價 프로세스에 관한 硏究

김영덕 忠南大學校 大學院 2009 국내박사

循環잔骨材를 使用한 纖維補强 콘크리트의 耐火特性에 關한 實驗的 硏究

진영삼 忠南大學校 産業大學院 2009 국내석사

Recently, the study is progressing actively about manufacture skill of concrete for promoted circulation aggregate and concrete made into circulation aggregate in the construction production field. But, application and study about circulation fine aggregate insufficient compared to circulation coarse aggregate. In addition, in case of the concrete used high quality circulation fine aggregate, the existing studies show that constructibility and dynamics performance are similar to the concrete used natural fine aggregate, but durability and long term stability are generally declined. To elevate reliability for maintenance management and longevity of concrete structure used high quality circulation fine aggregate and application of circulation aggregate, it need a formulate investigation about durability and long term stability. Studies on concrete that uses recycled aggregate gradually increase. It is necessary to produce high-strength concrete to meet the demand of densely populated and high-rising constructions according to industrialization and urbanization. Although high-strength concrete made of recycled aggregate has lower adhesive performance that natural aggregate, it is reported that it is possible to make high-strength concrete by recycled aggregate. Considering domestic construction markets where high-strength concrete is plainly used, it is urgent to establish the methods and standard of its fireproof design because it has higher spalling danger in fire and different strength according to exposed temperature than plain strength concrete. Studies on fire resistance performance of high-strength concrete made of natural aggregate has been done much both domestically and internationally. But those on fire resistance performance of high-strength concrete made of recycled aggregate are done a little. Therefore, it is time that social interest in studies on fire resistance performance of concrete made of recycled aggregate is needed. This study positively analyzes suitability of fiber contents technique, as a spalling control method when high-strength concrete make of recycled aggregate is set in fire, optimum fiber content ratio of fiber contents and selection of kinds of suitable fiber.

小型供試體에 의한 高强度콘크리트의 爆裂 및 高溫特性 評價에 關한 硏究

윤문기 忠南大學校 大學院 2009 국내박사

高靭性 콘크리트의 耐爆裂 및 耐衝擊 性能에 關한 硏究

이재문 忠南大學校 産業大學院 2009 국내석사

매트릭스 配合 및 製造方法에 따른 高靭性 시멘트 複合材料의 變形硬化 特性

백상엽 忠南大學校 産業大學院 2010 국내석사

건설재료로 가장 널리 사용되고 있는 콘크리트는 압축강도, 내구성이 우수하고 경제성이 우수한 성질을 가지고 있지만, 경화가 느리고 수축이 크며, 인장강도와 휨강도가 작으며, 인성이 작아 본질적으로 취성적 성질과 균열에 대한 저항능력이 작으며, 내약품성이 나쁘다는 등의 본질적인 결함을 갖는 취성재료로 알려져 있다. 그리고 구조물의 대형화 및 고층화에 수반하여 콘크리트 부재가 좀 더 세정화 됨에 따라 콘크리트의 취성개선은 물론 구조물의 균열발생 및 변형 등에 악영향을 미치는 건조수축 및 크리프 등의 장기변형 특성을 개선한 고강도․고인성이면서 치수안정성 및 신뢰성이 우수한 고성능․고품질 콘크리트의 개발이 크게 요구되고 있다. 특히, 최근 세계적으로 경제, 사회, 문화적으로 급변하는 발전 속에 고인성 시멘트계 복합재료의 필요성 콘크리트를 사용한 건축구조물에도 혁신적인 변화의 물결이 일고 있다. 즉, 보다 높고(초고층 구조물), 보다 넓고(장스팬-무기둥 구조물), 보다 깊은(심층지하구조물, 해양구조물) 구조물이 요구되고 있으며, 실제 이를 충족시킬 수 있는 구조물이 속속 등장하고 있다. 이러한 구조물들은 초기에 시공성 및 구조적 특성을 고려하여 철골조나 철골-철근콘크리트조 등으로 설계 및 시공되는 경향이 있었으나, 현재에는 고성능의 재료개발과 설계 및 시공기술의 발달로 고인성 시멘트계 복합재료를 개발·적용하고자 하는 노력이 계속되고 있다.

고로슬래그 치환율에 따른 콘크리트의 경화특성

이세범 충남대학교 산업대학원 2013 국내석사

본 연구에서는 고로슬래그 치환율에 따른 콘크리트의 경화특성에 대해 검토하고자 하였으며, 본 연구의 내용 및 범위는 다음과 같다. 제 1장에서는 본 연구의 서론으로서, 고로슬래그 미분말의 치환율이 콘크리트의 경화특성에 미치는 영향에 대한 본 연구의 배경, 목적, 내용 및 범위에 대하여 기술하였다. 제 2장에서는 본 연구에서 사용되는 고로슬래그의 개요 및 수화특성에 대해 서술하였으며, 고로슬래그를 활용한 콘크리트의 일반적인 특성에 대해 검토하였다. 제 3장에서는 본 연구를 수행하기 위한 실험에 관한 장으로써, 고로슬래그 치환율에 따른 콘크리트의 경화특성을 평가하기 위한 실험계획 및 방법, 사용재료를 제시하고, 실험을 통해 얻어진 결과를 검토?분석하였다. 제 4장에서는 본 연구의 결론으로서, 실험을 통해 얻어진 분석결과를 종합적으로 서술한 후, 고로슬래그 치환율에 따른 콘크리트의 경화특성 대해 검토하였다. Domestic steel industry has shown a rapid development and production of crude steel has been gradually increased annually thanks to continuous expansion of facilities and technology development. As a result, associated byproduct such as the amount of steel slag output is also expected to increase continuously. Thus, studies on recycling and making resource of steel slag have been conducted constantly to cut down disposing cost of waste as well as to contribute to conservation of environment. Steel slag has a number of recyclable resources such as iron, carbon, limestone, and etc. Therefore, reclamation of steel slag can lead to waste of resources and energy. Steel slag is typically divided into blast furnace slag and steel making slag, among which blast furnace slag has a high response, used concrete admixture. However, as its strength generation becomes low at its early stage and causes construction delay, the amount of being used as admixture is limited. Therefore, it is necessary to investigate its possibility of application as an activator’s admixture occurring in separate preliminary process of steel process. The purpose of this study was to investigate comparison of hardening properties of OPC concrete and concrete contained high volume blast furnace slag. The paper consists of as follows. Chapter 1 was an introduction of this study and provided background, purpose, methodology, and scope. Chapter 2 provided mechanical properties of activator and overview and hydration properties of blast furnace slag. Chapter 3 was an experimental study, providing methods were describe including research design, methodology, and using materials and the results were reviewed and analyzed. Chapter 4 includes the conclusions of the study, and describes the analysis results obtained from the tests and the meanings and action fields of the results. The result of this study are summarized as the follows : 1) The results of measuring slump and amount of air of concrete replaced with blast furnace slag were shown to satisfy target scope in all stages by introducing high performance superplasticizer and AE, concluding that they didn’t have any difficulty in construction. 2) The results of measuring setting time provided that it got delayed more as the replacement ratio of the blast furnace slag increased. Thus, it was needed for additional investigation to cut down the setting time. 3) The results of measuring compression strength of concrete, replaced with blast furnace slag showed that compression strength of early stage was increased and strength generation of its early stage was improved as the amount of CaO was increased inside of composite by mixing activator. As a result, it was expected that activator had a possibility to be used as admixture of concrete replacement of blast furnace slag. 4) Once additional investigation and criteria were supported by using industry byproducts such as blast furnace slag and activator, production of environmental load reduction eco-friendly concrete would be available.

Light gray 노출 콘크리트의 性能 : Urban Hive 建築現場을 中心으로

이정규 忠南大學校 大學院 2009 국내석사

Recently with the elevation of the standard of living and sense, the mental composure and the desire for affluence in a daily living highly demand the amenity and satisfaction with living. Accordingly the Architectural products are being developed in consideration of a user's sense like agreeableness rather than the center of performance in the past. This is also applied to the materials of architecture and expresses a higher level of request according to the performance of request rather than the satisfaction of the basic level of request by means of specifications. Therefore, I am putting an additional item other than high performance, high flow and high strength. The study is to define colored concrete expecting the gradual increase of demand in future and estimate the infinite possibility that concrete has in future based on current applied cases of Urban Hive. In the currents of times concrete structures increased in the use of the sensible phase but the definition and classification therein are insufficient, so it is necessary to survey and study the property of the concrete used for colored concrete, exposed concrete and other finishing. Therefore, in this research it intend to define and classify high Architectural concrete expecting the gradual increase of demand in future and estimate the infinite possibility that concrete has in future based on current domestic and abroad situations and applied cases. This thesis consists of as follows. This study is a part of the research about such colored concrete. Chapter 1 describes the introduction of this study, where we the objective, content and scope of this thesis in accordance with the increase of the demand in Architectural concrete. Chapter 2 describes a summary of Architectural concrete. we looked into the definition of colored concrete and preview and presented the general and material construction features and notes Architectural concrete has. Chapter 3 describes investigation of applicable possibility of colored concrete. we investigate a kind of factor that causes problem from plan to appling to colored concrete. and analyze mock-up test. Chapter 4 describes currently applied colored concrete of Urban Hive. we checked the required performance and necessary material features , and factor through carrying out. In Chapter 5, as a general conclusion of this paper, we thought of the future applicability on the basis of the analysis on the understanding and the applied cases of colored concrete based on current applied cases of Urban Hive. The result of this thesis can be summarized as follows. ◎ Summary of colored concrete performance (1) Colored concrete is required to be carful and give attention than general concrete. because condition change of unit water content, material couldn't keep up homogenization of building color over all. therefore it is required to check influence factor that is color and a kind of cement, aggregate, admixture, pigment (2) In general, colored concrete doesn't use other finishing materials on the surface of concrete and expresses itself by exposure and this area of sensibility concrete is expressed as Exposed Concrete. As sensibility concrete uses the surface itself as a finishing material, and in case of the same surface it is very important to express the same quality and color. Generally, the factors affecting the finishing surface are; ① Applied materials in concrete, ② Combination design and production method, ③ Cast and form oil, ④ Slip form method, ⑤ Hardening concrete state. Next, I'll suggest the factors affecting these colors such as general standard of sensibility concrete, request affairs and the property of the materials of concrete. ◎ Preview of color concrete applying to Urban Hive (1) Urban Hive project considers color pigment for the homogenized color, reducing cracking, the exterior structure of a building of honeycomb type, high strength concrete, using high-flowing concrete for dense filling, modifying ratio of chemical admixture for controling segregation, special admixture of treating surface for durability and water-repellent. (2) We investigate a problem according to a kind of mold and under the weather, effect of hydration heat according to structure shape, variation of outside strength according to curing time, a ratio and a kind of pigment for requested color through testing mock-up from starting work. ultimately we choice construction work in close proximity initial plan through confirmation of an owner and an designer (3) The problem to generate paste leakage in the surface solves change of pigment ratio, aggregate ratio (crushed aggregate : natural aggregate). a varity of problem is solved by change of treating surface of mold . also we could get the adequate color according to variation of pigment, cement. ◎ Color concrete applying to Urban Hive (1) Surface has structure that is consist of colored concrete of punching type of circle. the structure isn't divided into column, beam and wall. also, that has design of honycomb that regularly connects with RC cell of circle of 400mm thickness and 1050mm diameters this surface has a variety of prospect through an open window of circle and dynamic space by sunshine condition in indoor space as well as structure role. (2) Quality control of concrete is important in placing color concrete. but it also recommend attention to setting form, arrangement of bar, coating surface after removal of form, for express of requiring performance (3) In case of form, it needs to coat special parting agent close to form. it needs to compact in order of precedence. also when working, should keep in mind so that tamper does not close on the mold surface. high-flowing concrete of part exposed to air becomes fast. so we must progress tamping work at the proper speed.

레미콘 品質管理를 위한 單位水量 變動에 따른 콘크리트의 特性評價에 關한 硏究

정한영 忠南大學校 大學院 2009 국내석사

Generally, as unit water of concrete increases, concrete slump grows, which improves workability by increasing liquidity, and facilitating transport, placement, and compaction. However, when unit water inordinately increases due to manufacturing error of a cement mixer, coarse aggregate and mortar are separated, which increases free water that is not provided to hydration reaction with cement and eventually reduces durability by decrease of various airs and penetration resistance of salts. Also, it decreases concrete strength, which is the basic performance of concrete. Drying shrinkage increases, which generate shrinkage crack. Therefore, excessive increase of unit water easily generates quality problems of concrete. Thus, some Japanese government agencies defined their own management rules of change of amount of unit water to control the quality of concrete. However, these rules do not consider the quality of concrete after placement, and percentage of the manufacturing error and measurement error is their decision standard values. Meanwhile, the domestic rules evaluate slumps, air content, and chloride ion content of fresh concrete in a cement mixer. And then, compressive strength in strength management age defined in a specification is measured to decide whether concrete acquires proper quality. However, this kind of quality management item evaluates only liquidity of concrete and general durability and cannot predict performance that will be revealed after concrete is hardened in advance. Therefore, this study analyzes the development process of compressive strength, which is an item among those of concrete quality management to evaluate appearance of concrete as water is added to concrete. And it compares shrinkage and crack during the same period to present the basic data of quality management of cement mixers that will be used in the construction sites. This paper consists of as follows. In chapter 1, the necessity and purpose of this study is described. In chapter 2, this study aims at examining unit water of concrete theoretically and current measurement technology of unit water developed home and abroad. In chapter 3, by evaluating and analyzing concrete properties according to change of unit water, the basic data to improve quality management is presented. In chapter 4, the overall conclusion of this study is mentioned. The result of this study can be summarized as follows. ◎ A Study on Evaluation of Concrete Properties by Unit-Water Content Change for Quality Control of Ready Mixed Concrete (1) As unit water increases, compressive strength decreases. Based on standard design compressive strength and compressive strength degrading ratio , it is decided that unit water management standard is mixing strength +20kg/m3. (2) As unit water increases, drying shrinkage and restraint shrinkage contents increase as well. Specifically, in a case of in plat-ring type restrained test, more than 40kg/m3 increases, shrinkage content drastically increases. (3) In terms of crack evaluation such as days of cracks, space of cracks and increase of crack points, in a case of more than 40kg/m3 increases, there is a big difference from test piece smaller than 20kg/m3. (4) The results of evaluation of carbonation, indicate that as unit water increases more than 40kg/m3, velocity coefficient drastically increases. Years of durability are shorter than 10 years, which means performance of concrete decreases. (5) Through performance tests such as strength, shrinkage, crack and carbonation, properties of concrete according to change of unit water can be evaluated and the basic data for the future concrete mixer quality management will be presented.

循環잔骨材를 使用한 콘크리트의 工學的 特性에 關한 實驗的 硏究

임범수 忠南大學校 大學院 2009 국내석사

Recently, since big scale construction such as urban redevelopment project of big cities, residential land development, and road construction increases, it is expected that the amount of construction wastes rapidly increases, which leads to increase of waste concrete that occupies most of construction waste. Therefore, countermeasures to solve the problems are needed. And the natural aggregate will be dried up within 30 years due to the great amount of consumption in making of construction materials. For conserving natural aggregate resources, the waste concrete can be recycled as a important construction materials. Until now, the recycled aggregate manufactured from the waste concrete has been taken a side view of concrete. For the promotion of consumption of recycled aggregate, it is very important to make a study of manufacturing construction waste into good quality recycled aggregate and developing practical use for it. Therefore, this study evaluates quality performance of concretes that use recycled fine aggregate that is manufactured dry system technology to find out higher value-added use methods for waste concrete and total recycling of it. The contents and scope of this paper are as follows. In chapter 1, the background, necessities and purpose of this study were described. In chapter 2, it is abstract consideration about circulation recycled fine aggregate and recycled concrete, and it is investigated bibliographic data about properties and quality standard of recycled fine aggregate and recycled concrete. In chapter 3, it is the experiment about engineering properties of recycled fine aggregate concrete, and it is investigated and analyzed nature of fresh concrete which are airspace, slump, slump flow and bleeding base on ratio of recycled fine aggregate and S/a ratio and hardening nature of concrete which are compression strength, bending strength. In chapter 4, it is the experiment about engineering properties of recycled fine aggregate concrete, and it is investigated and analyzed nature of fresh concrete which are airspace, slump, slump flow and bleeding base on W/C ratio and unit water and hardening nature of concrete which are compression strength, bending strength. In chapter 5, overall conclusions were mentioned.

劣化條件 變化에 따른 콘크리트의 炭酸化 特性에 關한 硏究

정재민 忠南大學校 産業大學院 2009 국내석사

Concrete structures, which are widely used for construction, have been accepted as a semi-permanent material with good rust proofing and high durability properties due to its alkalinity. Recently, there have been cases where the structure’s life has been decreased due to various deterioration factors. Due to such concerns, various researches have been conducted to limit the concrete’s deterioration particles and improve durability. Also, it is reported that due to the dependence of the concrete structures on the surrounding environment’s deteriorating conditions, the deterioration is accelerated for underground structures, tunnels and other underlying structures. Hence, through this thesis we’d like to evaluate the life of a steel concrete whose carbonation is affected by carbon dioxide. Also, we’d like to study the initial research regarding the endurance layout of steel concrete. After the evaluation, we researched on the present condition of carbon dioxide formation within the underground structures. Furthermore, through an experiment that tried to examine the different environmental conditions causing deterioration, we were able to identify the characteristics of the progress of carbonation within the concrete. This can be used as the underlying data for future studies that will study more factors of the environmental conditions that affect concrete. An Study on the Carbonation Properties of Concrete according to Deterioration Conditions, this thesis consists of five chapters as follow ; In chapter 1 describes the necessity and purpose of this study. In chapter 2, 3 presents as a contemplation process of the related research, through this thesis we’d like to evaluate the life of a steel concrete whose carbonation is affected by carbon dioxide. Also, we’d like to study the initial research regarding the endurance layout of steel concrete. After the evaluation, we researched on the present condition of carbon dioxide formation within the underground structures. In chapter 4 contained an experiment that tried to examine the different environmental conditions causing deterioration, we were able to identify the characteristics of the progress of carbonation within the concrete. This can be used as the underlying data for future studies that will study more factors of the environmental conditions that affect concrete. In chapter 5 presents the overall conclusion. ▣ As the result of 'A Study on the Carbonation Properties of Concrete according to Deterioration Conditions', we got the following conclusion. (1) This thesis was able to find through the underground structure’s (subway) air evaluation that such an environment generated 1.5 times more carbon dioxide than the exterior environment. With the characteristic of the underground interior, the temperature and humidity is thought to be maintained regularly. (2) Through evaluating the absence of carbonation, in underground structures such as a tunnel the density of carbon dioxide is higher than the regular exterior carbon dioxide density of approximately 350ppm. The density and temperature that most facilitates carbonation process is density of 40~60% and a temperature of approximately 20℃. As a result of the carbonation evaluation, the damage due to carbonation was rapidly accelerated. (3) After the evaluation of the carbonation due to the accelerated carbonation condition, the higher the temperature, the lower the corresponding humidity, and the higher the CO2 density, the better the deteriorating environment is established. (4) Further experiment is necessary to apply the conditions to accelerate carbonation in actual concrete structures. We believe that further deterioration factors should be introduced to the environment.