콘크리트는 우수하고 뛰어난 내구성에 의해 구조물 건설에 가장 많이 사용되는 재료 중 하나이다. 오늘날 급격한 경제의 발전 및 도시화 등에 의해 오늘날 구조물은 대형화 및 고층화되고 있다. 이에 따라 고강도, 고경량, 고내구 콘크리트 개발에 대한 다양한 연구가 진행되고 있다. 특히 나노소재가 첨 가된 콘크리트는 나노소재에 의해 미세공극이 충진되어 강도 및 내구성이 우수한 것으로 알려져있다. 그러나 기존 나노소재가 적용된 콘크리트는 단위중량이 높아 이를 구조물에 적용시 자중을 증가시키 는 단점이 있다. 이에 본 연구에서는 입자 직경이 10-100 μm이지만 입자 내부의 공극이 있어 단위 중량이 0.6t/m3인 Micro hollow sphere가 잔골재로 사용된 고경량, 고강도 콘크리트의 염화물 침투 특성을 평가하였다. 본 연구에서 사용된 실험변수로써 Micro hollow sphere의 잔골재 치환량(0%, 42%, 100%)가 고려되었으며, 이 시편의 단위중량은 각각 2.37 t/m3, 1.89 t/m3, 1.62 t/m3이다. Micro hollow sphere가 사용된 콘크리트의 염화물 침투 특성은 NT-Build 492 시험을 통해 평가되었다. 실 험결과 Micro hollow sphere 치환율이 0%, 42%, 100%인 실험체의 단위중량은 염화이온 확산계수는 각각 4.45 x10-13 m2/s, 2.57 x10-13 m2/s, 1.4x10-13 m2/s로 Micro hollow sphere 치환량이 증 가함에 따라 염화이온 침투 저항성이 증가하는 것으로 확인되었다. 따라서, Micro hollow sphere를 이용한다면 단위중량이 작으며 내구성이 큰 고경량, 고내구 콘크리트 배합이 가능할 것으로 판단된다.

최근에는 대규모 건축 및 토목 구조물로 인해 건설 부재의 고강도 및 경량화에 대한 요구가 높아지고 있다. 기존의 경량 시멘트 복합체의 경우 단위 체적 중량이 낮아질 수 있으나 강도 저하 문제가 발생한다. 일반적으로 경량화를 위해서는 시멘트 복합체를 배합할 때 일반 경량골재와 고무경량골재, 플라스틱 펠릿 등 다양한 인공 경량골재를 이용한 시멘트 복합체를 혼 합하여 경량화를 확보할 수 있다. 이 중 시멘트 복합체의 인공 경량골재로 플라스틱을 사용하면 상대적으로 골재 자체의 강도를 확보할 수 있지만 재료의 표면 특성으로 인해 시멘트 페이스트에 부착하는데 불리하고 골재로서의 사용이 불리하다. 이에 본 연구에서는 골재로 가장 적합한 플라스틱의 유형을 선택하기 위해 다양한 유형의 플라스틱 시멘트 화합물을 변수로 하여 실험을 진행하였고 실험 결과 플라스틱의 비중이나 표면 재질에 의해서 시멘트 복합체의 물리적 성질이 변화하는 것을 확인할 수 있었다.

In korea, only small amount of nonstructural lightweight concrete is being used through indirect effects such as heat insulation property and soundproofing rather than structural elements due to lack of structural lightweight aggregates and lack of understanding about lightweight concrete development, etc. That`s why structural lightweight concrete to reduce weight has not been put to practical use. This study is a part of high strength lightweight aggregate concrete researches using lightweight aggregates and the purpose of this study is to find out the basic physical characteristics and tension cracking fracture characteristics of lightweight concrete. Crack Mouth Opening Displacement is measured through 3 point flexure experiment about notch beam. Load-CMOD characteristics are examined through rules of countries, characteristics of lightweight concrete and tension cracking fracture experiments. The degree of tensile characteristic alteration according to size changes of specimen and the characteristics about crack surface are analyzed. The changes of softening curve are analyzed and fracture energy is drawn through inverse analysis by the obtained Load-CMOD curve. To decide fracture energy and analysis parametric, inverse analysis is conducted and Ant Colony Method is conducted for optimization and then a way to find out optimal parameterization fracture energy is suggested.

This study is a part of high strength lightweight aggregate concrete researches using lightweight aggregates and the purpose of this study is to find out the basic physical characteristics and tension cracking fracture characteristics of lightweight concrete. Crack Mouth Opening Displacement is measured through three point flexure experiment about embellish notch beam. Load-CMOD characteristics are examined through rules of countries, characteristics of lightweight concrete and tension cracking fracture experiments. The degree of tensile characteristic alteration according to size changes of specimen and the characteristics about crack surface are analyzed. The changes of softening curve are analyzed and fracture energy is drawn through inverse analysis by the obtained Load-CMOD curve. To decide fracture energy and analysis parametric, inverse analysis is conducted and Ant Colony Method is conducted for optimization and then a way to find out optimal parameterization fracture energy is suggested.

대표적인 다상 재료인 콘크리트는 구성 성분의 공간적 분포에 의해 재료 특성이 큰 영향을 받는다. 특히 공극(void)은 콘크리트의 특성에 큰 영향을 주는 요인으로서, 콘크리트 내부에 분포하는 공극의 공간적 분포를 파악하는 것은 재료의 특 성을 이해하는데 매우 중요하다. 본 연구에서는 콘크리트 내부에 존재하는 경량 골재의 공극 분포 분석을 위해서, CT(computed tomography)로부터 얻은 단면 이미지를 활용하여 생성된 3차원 경량 골재 이미지를 활용하여 공극 분포를 시각화(visualization)하였다. 방향에 따른 3차원 경량 골재 내부의 공극 분포 상태를 정성적으로 묘사하기 위해서 확률 분 포 함수인 두점 상관함수(two-point correlation function)를 사용하여 공극의 공간적 분포 경향을 구(sphere)에 표현하였다. 또한 방향에 대한 골재의 강성도(stiffness)를 계산하여 각 방향에 따른 골재의 역학적 물성치 분포 변화를 확인하였다. 각 방향으로의 확률 분포 함수로 표현된 공극 분포와 강성도 분석함으로서 CT 이미지를 통한 공극 분포 특성 분석 및 경량 골재의 역학적 특성을 효과적으로 예측할 수 있음을 확인하였다.

The flexural strength of lightweight aggregate concrete (LWAC) T-beams reinforced with the minimum amount of longitudinal reinforcement could be conservatively predicted by the conventional procedure using the equivalent stress block specified in concrete code provision.

This study investigated the properties of lightweight foamed concrete by using surfactant and synthetic foaming agent, lightweight aggregate. The effects of foaming agent types and replacing ratio of lightweight aggregate on the compressive strength, density and pore structure of the concrete were investigated. This study showed the improvement of important properties of lightweight foamed concrete. Lower pore distribution and correspondingly higher compressive strength values were reached. Also, synthetic foaming agent had more positive effect on the strength of foamed concrete.

This study was conducted examine the mechanical properties of LEFC in relation to the type of light weight aggregate and replacement ratio. For the specimen, different replacement ratio was used for recycled waste ALC and the bottom ash light weight aggregate respectively. The tests revealed that 60% of the waste ALC light weight aggregate is suitable for securing the optimal strength and light weight of the LEFC.

This study was conducted examine the mechanical properties of LEFC in relation to the type of light weight aggregate and replacement ratio. For the specimen, different replacement ratio was used for recycled waste ALC and the bottom ash light weight aggregate respectively. The tests revealed that 60% of the waste ALC light weight aggregate is suitable for securing the optimal strength and light weight of the LEFC.

In this study, it is conducted analysis of water absorption of artificial lightweight aggregate using coal ash. For absorption of water, the artificial lightweight aggregate was submerged for 24hours or in conditions of high temperature(100℃) and normal pressure. And it was measured water absorption ration and density( in conditions of oven-dry and saturated surface dry).

In this study, high strength concrete with satuated artificial lightweight aggregate(SLWA) produced by domestic for reducing autogenous shrinkage, which provides additional water to the hydratin cement particles, is applied to be the internal curing. This paper presents the test result of basic property of SLWA and autogenous shrinkage with volumes of SLWA.

Differential scanning calorimetry of the aggregated impregnated with PCM indicates 4～10 J/g of the amount of heat storage capacity. The results show that it is considered that lightweight aggregate concrete impregnated with PCM may have thermal energy storage capacity.

In this paper, was examined the basic properties of mortar using perlite, vermiculite, natural and artificial lightweight aggregate as a part of the basic study for development of lightweight repair mortar.

The components of municipal solid waste incineration bottom ash produced over 3 million ton every year are similarto the components of geological features, therefore it is suitable to be used as the raw materials of lightweight aggregate.Development of lightweight aggregate using this bottom ash will be helpful to solve landfill and environmental problems.Lightweight aggregate was developed at 1,110oC by using clay, kaolin, bentonite and silica as the raw material to 50%of municipal solid waste incineration bottom ash. Silicon carbide (SiC) was used as a blowing agent. Optimal mixingratio is bottom ash 50%, kaolin 22%, clay 22%, bentonite 6% and blowing agent 0.1%. As the result of quality test,produced lightweight aggregate met the all appraisal standards. The result of heavy metal leaching test was much lowerthan the elution reference value of ceramic manufactures made by using bottom ash.

In this study, natural fine aggregates(NFA) and recycled fine aggregates(RFA) was applying in the lightweight foamed concrete. To replacement of OPC, high volume blast furnace slag was used and incineration ash and recycled aggregates powder were used as alrali activator, Fundamental performances of lightweight famed concrete has been tested. Results showed that as the increase of foam conduction ratio, the strength and the density has been decreased

In this study, trying to applying in structure and slab and wall of technical of near-surface transit system, we would make precast concrete for constructing rapidly to diversify subject about lightweight concrete. for this purpose, we experimented lightweight aggregate centrally expected to be applied in this research and would like to suggest fundamental data for manufacturing products as a level of 30, 50MPa precast concrete.

Based on Measurement of the dynamic Modulus of Elasticity Lightweight Aggregate Concrete using USPV. Depending on the materials used absolute difference in dynamic modulus of elasticity was verified, but increasing load was caused Ultrasonic velocities increase, and accordingly the relative value increase in dynamic modulus of elasticity identical trend was confirmed.

The energy consumption by buildings approximately reaches 25% of total korea energy consumption. The greatest part in the buildings of the energy consumption is building facade. but a few research projects on concrete comprising more than 70% of outsider of buildings has been tried. This research structural insulation concrete what improved insulation performance using micro form admixture and lightweight aggregate.

Recently, it is requests the reduction of self-load at structure and the cross section reduction due to the trend of making higher, larger of buildings. But The experiment of Lightweight concrete is mostly implemented in Laboratory and is rarely implemented in patch plant for application of construction site. therefore, this study will be useful at base, when the lightweight aggregate concrete is applied to construction site. so We had a comparative experiment of physical performance with in laboratory and Batch plant for lightweight aggregate concrete.