This paper shows examples of damage cases for corrugated steel plate structures in Korea expressway. There are two representative types of damages. One is a water leak and the other is the deformation of inner section. The results of this study will be useful for future maintenance of corrugated steel plate structures.

Recently, the concern on the deterioration of concrete due to de-icing salts and its counter measurements has been increased. This paper discusses the results from investigation of pre-mature deteriorated existing road-subsidiary concrete structures and the specification of concrete quality.

The present study concerns a measurement of porosity at the nano-fibre interface in concrete. Concrete cast with a centrally located nano-fibre (Ø0.39 × 15.0 mm) was segmented for microscopic observation at a bascattered electron (BSE) image. As a result, it was found that the pores generated in the vicinity of the nano-fibre ranged from 5.40 to 11.45%, equivalent to 0.51 - 1.08% of air void in a bulk concrete.

Preliminary tests confirmed that the addition of nanoscale composites possess significant potential to provide mortars with purification properties.

In the current concrete structure of the highway is still the major problem most of concrete deterioration caused by the freeze-thaw and de-icing salt, which is of issues that are not completely resolved. In particular, a single freezing event does not cause much harm, durability of concrete under multi-deterioration environment by repeated freeze-thaw and de-icing salt is rapidly degraded and reduce its service life. In this study, to considering environmental characteristics when design and construction of concrete structures, the exposure environmental guidelines were established by investigation the application rates of de-icing salt, temperatures and snowfall characteristics during five years (2004∼2008) by regions. Also, damage condition and chloride content of the structural at regions of moderate and severe environmental exposures were investigated.

The purpose of this study is to evaluate the impact on flexural strength and compressive strength of the concrete, the mixing rate of the amorphous fibers.

Traditional methods for concrete structure demolition is not adequate specially for urban areas and historical places due to hazard of explosive and noise. Therefore, Soundless Chemical Demolition Agents (SCDA) is useful in urban area and historical places. In this study, a analysis for SCDA is performed depending on boundary conditions.

This study is corroborated as a fundamental resource to develop structural lightweight foamed concrete. Mortar using foaming agent decrease over 0.3 g/㎤ of weight of unit volume and increase over 27 MPa of compressive strength available structural purpose. After that, it is compared with Young's modulus of experiment and analysis from FEM analysis using SEM image.

This study investigated the applicability of synthetic resins as neutron shielding aggregates in cementitious materials with SEM analysis. Synthetic resins contain lots of hydrogen atoms, which is effective in neutron shielding by an elastic scattering because its mass is almost the same as that of the neutron. The SEM results showed that the binding force between HDPE/PP particles and cement matrix is very week compared to that of UPE particles so that additional treatment such as surface reforming should be needed.

A new approach to evaluate the durability of concrete structures was proposed in this study, which additionally considered the time-dependent and environmental effects, especially freezing-thawing and salt attack. This might have a potential for the reasonable durability evaluation with the systematic management of SOC facilities.

This study aimed to propose a reasonable performance evaluation process of freeze-thaw and carbonation depth on concrete structures, especially considering the time-dependent and environmental effects, to develop a long-term maintenance plan in Korea.

본 논문은 CFRP로 보강된 RC 구조물의 공기층 검측장비 개발을 위하여 수행된 선행 실험 연구 내용이다. 실험 결과로 측정된 저항치는 공기층의 존재 유무에 의해 영향을 받는다. 측정된 저항치 는 개발장비의 유용한 정보로써 사용될 것이다.

This experiment can maximize the decline of the heat on steel structure by using the magnesium hydroxide and aluminum hydroxide which generally used to resistant or retardant. These materials can delay a temperature rise due to the generation of vapors around the fire resistive covering, when reacting with heat by a creating moisture. Therefore, applicability of the fire resistance mortar used magnesium hydroxide and aluminum hydroxide was studied and experimented. As a result, in case of the workability is satisfied with the condition of site, but in case of the bonding strength is not satisfied with the standard with fire resistance mortar.

A state-of-the-art safety management system of water infrastructures based on ICT Technology is now under development by incorporating 1) real-time safety evaluation system, 2) disaster risk management support system based on GIS, and 3) decision-making support system for damage restoration equipped with multi sensor information acquisition system such as UAV and CCTV. This study includes development of practical natural disaster scenarios for flooding, typhoon and earthquake events based on recorded data, and standardization of disaster management platform.

Recently efficient maintenance technology has been rising because of the structural deterioration. Specific technology development and research related to the real-time monitoring has been conducted in various ways. All-in-one enclosure including GPS was fabricated to measure the displacement of the retaining wall structure exposed the extreme environment such as very high and low temperature. Also it measured the displacement of the structure under the phased construction.

Membrane structure is a system that is stabilized by maintaining a tensile state of the membrane material that originally cannot resist the bending or pressure. Thus, it is important to accurately understand the size of the membrane tension after the completion of the structure, for maintenance and management purposes. The author of this paper measured the tension of preexisting membrane structure for its maintenance purpose by using the developed portable measurement equipment. Through analyzing the measurement data, the author check the points that should be improved and the technical method for the new maintenance system of membrane tension.

This paper describes the effect of norton tape and boundary sealant on structural performance of structural sealant glazing(SSG) system. A total 3 specimens were made and tested under four point loading condition. In this study, it was found that norton tape and boundary sealant considerably affects the structural performance of SSG system.

This study relates to a crack repair techniques in the concrete structure. In order to develop repair material containing self-healing agents, smart repair methods were investigated. For the micro cracks of less than 0.3 ㎜, new repair method of surface treatment was suggested by the simple crack repair stick. In case of over 0.3 ㎜ cracks, injection method using inorganic materials was suggested for drying shrinkage and water leakage.

This paper presents a new strengthening method for underground RC box structures against seismic loads. results confirmed that the proposed pre-flexed member system can enhance the seismic capacity of the underground RC box structures