Bond characteristic between lightweight concrete and helically deformed GFRP bar was investigated in this study. Three main parameters were considered in experimental investigation: type of rebar, concrete type, and compressive strength of lightweight concrete. As an experimental result, it could be known that bond strength of the helically deformed GFRP bar in the lightweight concrete was 0.49 times bond strength of steel reinforcement in normal concrete

As the scale of structure becomes larger, the temperature crack of massive concrete structure is caused by the phenomenon which the mass concrete volume is restricted in the inside or outside part due to the temperature variations induced by the hydration heat of cement. So, we should prepare the method to reduce reasonably the hydration heat for the control of temperature crack. Therefore, this study presents the hydration heat analysis to verify the control effect of temperature crack when we consider to the different concrete mixtures.

This study investigates the effect of emulsified refined cooking oil (ERCO) on the fundamental properties of cement paste, and their results are compared with that of shrinkage reducing admixture (SR). Results showed that ERCO decreased early strength, but retained the strength at the later age of 28 days, slightly higher than pure OPC

This study utilized atomic force microscopy (AFM) and nanoindentation methods to evaluate epoxy water-resistance and anti-corrosiveness. This study considered two different epoxy formulations to assess typical degradation characteristics of epoxy surfaces with regard to water-resistance and anti-corrosiveness. As a result, this study was able to clearly confirm changes in physical characteristics and performance tendencies regarding ozone oxidizing reactions.

This paper is to investigate experimentally the effect of waste cooking oil on compressive strength and chloride penetration resistance of high volume fly ash and blast furnace slag concrete. According to results, the incorporation of waste cooking oil resulted in an improvement of penetration resistance of chloride.

The objective of this research is to evaluate the fireproof covering thickness of concrete-filled tube columns(CFT) by finite element results using ABAQUS package program. As a result of this study, there is a huge difference between the analytical results and Korean fire resistance criterion

본 논문은 MWCNT의 전기적 특성을 가지고 포틀랜트 시멘트와 혼합하여 전기저항성 테스트를 통해 전자파차폐에 대한 연구를 하였다. 시험 방법은 MWCNT를 0wt% ~ 3.2wt%까지 0.2wt% 증가시 켜 시멘트와 혼합하여 공시체를 생성하였다. 저기저항성 결과 1.8wt%까지는 저항이 높은 것으로 나왔으며 이는 전자파 차폐에 대해서 차폐율이 높지 않을 것으로 판단되며, 혼합량 2wt%부터는 전기 저항성이 낮게 나와 전자파 차폐에 대해서 효과적으로 나타날 것으로 판단된다.

Since electrical resistivity of concrete can be measured in a more rapid and simple way than chloride diffusivity, it should be primarily regular quality control of the electrical resistivity of concrete which provides the basis for indirect of quality control of chloride diffusivity during concrete construction. If this is realized, the electrical resistivity of concrete can be a crucial parameter to establish maintenance strategy for marine concrete structures. The purpose of this study is to develop, design and test a surface electrical resistivity measurement protocol. The outcome of this study can provide a non‐destructive approach that assists in identifying the bulk concrete resistivity which can then be correlated to chloride diffusivity.

Heat insulator materials can be classified inorganic and organic. The organic material is due to toxic gas emission, when a fire occurs. And it has lower water resistance. The inorganic material is heavy and worse thermal performance than organic materials. This study focused on evaluation of the physical properties of light-weight inorganic foam panel for using industrial by-products materials and performance evaluation by mock up test.

Quantification of incoming-salt in the air is absolutely critical for the use of the boundary conditions in chloride resistance design. Thus, as a result of collecting incoming-salt by using multidirectional incoming-salt collector, it was confirmed that incoming-salt was collected not only in the direction of viewing the coast but also in the opposite direction. For this, it is believed that it is necessary to analyze the relationship between the effective defense incoming-salt and the non-effective defense incoming-salt that is delivered through a local flow of surrounding wind

Up to date, the specifications of construction and maintenance for airport pavement are primarily from ICAO (International Civil Aviation Organization), IATA (International Air Transport Association) or FAA (Federal Aviation Administration). In order to consider circumstances such as rainfall characteristics, this study aims to develop pervious concrete for base course of an airport pavement. Strength characteristic of pervious concrete was investigated with respect to different maximum course aggregate size. When 25mm sized aggregate was used, greatest strength was achieved.

Domestic expressway are exposed to damage of combined deterioration by excessive use of deicer and a lot of cost is required for maintaining damage structures. Therefore, now is the time that durability of subsidiary concrete structures is required to enhanced in order to reduce maintenance cost of structures and to promote road safety. Thus, in this study measured compression strength and scaling resistance of concrete using the waste glass sludge

In this paper, neural network technique(NNT) is applied to estimation of chloride diffusion coefficient, which has been used for strength evaluation and concrete mixing design. Rapid chloride diffusion test is performed for concrete with 3 different w/c ratios (0.37, 0.42, and 0.47) and various mineral admixtures such as GGBFS, FA and SF. Regarding 120 obtained diffusion coefficients, NNT is applied and diffusion coefficients are simulated. Utilizing the technique, chloride behavior in concrete is evaluated through FE model based on Multi-Component Hydration Model and Micro Pore Structure Formation Model. The simulated results are verified with the previous test results which have been exposed to sea water for 6 months.

This study is on the correlation between the capacity of the city, and floor area of super-tall buildings. Land use affects on a floor area by use of super-tall buildings, and amenities and public facilities affects too. As a result, the appropriate size of the super-tall buildings on the capacity of the city will help in the development of the district region.

To improve fatigue strength of fillet-welded joints by hammer-peening treatment, fatigue tests were carried out on three types of longitudinal out-of-plane gusset fillet-welded joints and transverse non-load carrying cruciform rib fillet-welded joints: as-welded joints, post-weld hammer peened joints and hammer peened joints at 50% of as-welded joint’s fatigue life. From the test results, the effect of hammer-peening treatment on fatigue behavior of the fillet-welded joints were presented

In this study, it was developed eco-friendly geopolymer concrete using ground granulated blast furnace slag and alkali activator(water glass, sodium hydroxides). Also, it was evaluated the flexure capacity of the RC beams using geopolymer concrete. The eco-friendly concrete using geopolymer encouraged alkali activation reaction has rapid hardening speed and showed possibility as a high strength concrete. Also, the RC beams applied this showed similar movement and destroy tendency with RC used previous cement

This paper describes evaluaties the mechanical characteristics of high strength steel fiber-reinforced concrete(SFRC) with maximum size of coarse aggregate. The test variables such as aggregate maximum size(8, 13, 20mm) and steel fiber volume faction(0, 1.5%). The test results indicate, SFRC of smaller aggregate size is expected to prvention of brittle fracture and promote of compression toughness.

In this study, we investigated the physical properties and thermal behaviors of specimens that applied different mixing ratios of foaming agent to evaluate the possibility of use in the structural elements. We proposed the estimating equation for compressive strength of each mix having different ratio of foaming agent. We also confirmed that the density of cement matrix is decreased as the mixing amount of foaming agent increase up to 0.6% of foaming agent mixing ratio which was observed by SEM. Based on porosity and compressive strength of control mortar without foaming agent, we built the estimating equations of compressive strength for mortars with foaming agent

The PHC pile offers high compressive strength, resistance to bending moment, economic efficiency and many other benefits. Being vulnerable to lateral force, however, it can only be applied in limited situations in which the strong lateral force doesn't need to be put in place, thus requiring the development of new forms of pile. For this reason, this study produces a concrete-Infilled Composite PHC pile(ICP pile) reinforced with shear reinforcement and ilfilled concrete and conducts a shear test according to KSF 4306.

To the goal of improving the early compressive strength of the mortar including Ground granulated blast furnace slag under low-temperature environment, Industrial byproducts including SiO2 and Al2O3 was fired and than 7% of it was added into Ground granulated blast furnace slag. By checking compressive strength and activity index from different mixing rate, in spite of low strength development than OPC 100%, when using firing powder, the expectation of increasing strength by curing time was affirmative