• Journal of the Korean GEO-environmental Society
• /
• v.13 no.8
• /
• pp.5-13
• /
• 2012

This research have investigated the application and the injection effect of the alkaline silicasol grouting materia (which is) recently developed. To compare the engineering characteristics of the alkaline silicasol which is formed with 3D-gel and the sodium silicate, it have studied the strength and environmental effects through the laboratory test, and field application was investigated with a review of the injection effect and waterproof through the field test. As a result of the laboratory test, unconfined compression strength of alkaline silicasol was 5 times more than sodium silicate. As a result of the leaching test, a total amount of the eluviated elements was very small, it considered the environment-friendly material. As a result of the field test, considerable reduction of the coefficient of permeability at the hydraulic layer was confirmed, and it could secure that the coefficient of permeability showed a lower than standard value of $10^{-5}cm/sec$.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.11 no.1
• /
• pp.59-66
• /
• 2011

Lifeline Damages induced by earthquake loading brings not only a structure damage but the communication problems by the interruption of various energy utilities such as electric power, gas, and water resources. Earthquake loss estimation systems in USA and Japan, called as HAZUS (Hazard in US) and HERAS (Hazards Estimation and Restoration Aid System), respectively, have been established for the purpose of efficient responding to the earthquake hazard. Sufficient damage records are required to establish these systems. However, there are insufficient data set of damage records obtained from previous earthquakes in Korea. In this study, according to the construction specifications of the pipelines in both Korea and USA, the behavior of both ductile and brittle pipelines embedded in dense sand overlying various soils, such as clay, sand, and gravel were examined with respect to the pipeline characteristics under various earthquake loadings. The applicability of pipeline damage prediction used in HAZUS program to Korea has been investigated.

• Journal of the Korea Concrete Institute
• /
• v.25 no.4
• /
• pp.411-418
• /
• 2013

Recently, in order to reduce a damage of chloride attack and hydration heat in marine concrete structures, blended cement in mixing the marine concrete is widely used. Long term strength development is distinct in concrete with blended cement and it also has excellent resistance to chloride attack and reduction of hydration heat. However, blended cement has a characteristic of relatively low compressive strength in early age of 28 days. On the other hand, a high level of compressive strength is required in the Standard Specification for marine concrete mix design. Such concrete mix design satisfying Standard Specification is effective to chloride attack but disadvantageous for hydration heat reduction due to large quantity of binder. In this study, the material properties of marine concrete considering water-binder ratio and binder type are experimentally investigated. Through the research results, compressive strength in blended cement at the age of 56 days is similar although it has smaller compressive strength at the age of 28 days compared with result of OPC (ordinary portland cement). Even though blended cement has a large water-binder ratio and small unit of binder content, chloride ion diffusion coefficient is still small and hydration heat is also found to be reduced. For meeting the required compressive strength in Standard Specification for marine concrete at 28 days, the increased unit content of binder is needed but the increased hydration heat is also expected.

• Journal of the Korean Geosynthetics Society
• /
• v.9 no.1
• /
• pp.39-46
• /
• 2010

Recently, the effective use of closed waste landfill nearby urban areas has been demanded, because of the lack of the usable land. However, the reuse of closed landfill is needed an adequate stabilization of liner system. But most of these places are consisted of steep slope and hence it is necessary to use the geosynthetics liners in there. Liner system of waste landfills is an important facility which prevents leachate outgoing from the landfills and also groundwater infiltrating from surroundings into the landfills. During the waste disposal stage, differential settlement and tensile stress of the geosynthetic materials could occur due to impact load of trucks and dozers, waste loads and weak foundation soils. In this study, the tensile strength and tracer test were performed to evaluate the stability of geomembrane liner systems. Based on the tensile strength test result of in-situ geomembrane sample, the yield tensile strength maintain the suitable strength by specification and current law. However, according to the tracer test, the damage of geomembrane liner was detected on sanitary landfill section.

• Journal of Korean Society of Steel Construction
• /
• v.22 no.6
• /
• pp.581-588
• /
• 2010

Recently the requirements of the buildings built with structural steel were increased in terms of structural stabilities and fire resistance at severe fire conditions. To meet the building regulations of fire resistance, a fire design is needed. This is of a prescriptive method and a performance engineering based method. Recently a simple calculation method as one of performance based engineering method is very popular because of its ease for an application in building built with structural steel. But, in Korea the performance based engineering method is not allowed yet. Thus it is needed to make a guideline for the performance based engineering method. The purpose of this study is to establish the limit temperature derived from structural beams made with both a H-section and a H-section filled with concrete at the web and derived the limit temperatures from beams made with H-sections and found out that the limit temperatures from two kinds of specimens depended on the applied loads and the specimens filled with the concrete represented 3 hour fire resistance in the range of 80%, 60%, and 50% of the maximum load.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• 2004.11a
• /
• pp.358-361
• /
• 2004

The objective of establishing IETM (Interactive Electronic Technical Manual) is not the just making into on-1 me system of technical manuals such as specifications. It is to produce construction standard documents in an electronic manual system to turn technical contents such as construction methods in technical manuals into multimedia information. Also, it is to maximize real-time information delivery by using visual data of construction sites. IETM enables to check not only design standards in the design but also applied situation of a construction method based on proper design standards and historical construction data on a real time basis. This study suggests a modeling method of IETM applicable to design and construction phase. The study includes a framework and a scenario for developing design IETM for construction project.

• Journal of Korean Society of Steel Construction
• /
• v.9 no.3 s.32
• /
• pp.301-307
• /
• 1997

In field fabrication of steel members, the oversize hole is frequently required due to reaming and mismatching. But, there are no provisions and investigations about oversize hole in the Korean specifications. So, in this study, the tension test of friction type high-tention bolted joints is performed with parameters of bolt hole size, surface treatment and tightening force, and investigate the effect of slip behavior with those parameters. From the results, the enough tightening force is needed to obtain some degree slip load in shot blast treatment case, although tightening force is reduced somewhat, it is no problem to guarantee slip load in zincrich primer case. The slip behavior of joints with oversize hole(26mm) is similar to the slip behavior of joints with hole of nominal size.

• Journal of the Korea Concrete Institute
• /
• v.18 no.4 s.94
• /
• pp.543-552
• /
• 2006

The current design for crack width control in concrete bridges is incomplete in analytical models. As one of the important serviceability limit states, the crack width be considered with the quantitative prediction of the initiation and propagation of corrosion and corrosion-induced cracking. A serviceability limit state of cracking can be affected by the combined effects of bond, slip, cracking, and corrosion of the reinforcing elements. Considering life span of concrete bridges, an improved prediction of crack width affected by time-dependent general corrosion has been proposed for the crack control design. The developed corrosion models and crack width prediction equation can be used for the design and the maintenance of prestressed and non-prestressed reinforcements by varying time, w/c, cover depth, and geometries of the sections. It can also be used as the rational criteria for the maintenance of existing concrete bridges and the prediction of remaining life of concrete structures.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.20 no.1
• /
• pp.112-117
• /
• 2016

For artificial ground greening construction without root-proofing layer, this research reviewed the effect on watertightness of asphalt waterproofing layer by plant roots penetration based on crack width, and crack penetrated roots. Experiment on concrete crack width was performed with three conditions such as 0.15, 0.30, and 0.45 mm, and all three conditions confirmed that all plant roots penetrations were made through crack area in 12 ~ 18 months. In addition, according to evaluation of effects on waterproofing layer by crack penetrated plant roots and in condition of 0.45 mm crack width, it indicated that penetration is made on asphalt waterproofing layer in 12 months due to roots penetration.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.34 no.6
• /
• pp.1743-1751
• /
• 2014

It is well known that latex modification can lead to enhancement compressive and flexural performance, tensile bond strength, chloride penetration resistance and freezing-thawing resistance for concrete. For these, many studies for LMC pavement have been widely conducted more than those for conventional pavement concrete. However, due to several problems such as noise and construction cost, new approaches for LMC have been executed to improve the performance of LMC. Recently, Remicon LMC was developed in order to solve the problems of LMC. In this study, the durability of Remcion LMC was compared with latex and mineral additive mixing ratio. From the results, when latex and mineral additive were mixed in Remicon LMC, compressive, flexural and bond strength were satisfied with Korea Highway Construction Guide Specification. And, it showed that the qualitative effect of latex and mineral additive mixing ratio on the durability of Remicon LMC was investigated experimentally. Also, the latex mixed in Remicon LMC must be at least 8%, in order to ensure the durability equivalent or higher than conventional LMC.