• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.5
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• pp.75-81
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• 2011

Recently prestressed concrete bridges are generally used instead of reinforced concrete. PSC is more durable than RC because it can reduce crack problems, reinforcement corrosion, leakage and carbonation etc. And also PSC is more effective because there is no crack in tension area, and the entire concrete section is considered in section analysis. And it can reduce section size because vertical component by prestressing force can reduce the shear force. However, using high strength concrete can increase the self weight of bridge because of it's higher density. So the hollowed PPC girder with light weight aggregate can be a alternative. In this study the hollowed PPC girder with light weight aggregate is designed and the performance of hollowed PPC girder is evaluated by experimental tests as well as numerical analysis. As a result, The hollowed PPC girder of light aggregate behaved fully elastically under service load of 110kN, and the plastic behavior was showed after elastic behavior through experimental test, and it can be also estimated by numerical analysis.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.589-592
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• 1999

This paper is experimental study on the flexural strength and ductility capacity of reinforced high-strength concrete beams using fly ash artificial lightweight concrete beams and five reinforced high-strength normal concrete beams with different tensile reinforcement ratio were tested to investigate their behavior. Test result show that the ratio of flexural strength between experimetal results and those by ACI code decrease as the compressive strength of concrete increase. Also, The reinforced concrete beams behave more brittly than those with equal reinforcement ratio($\rho$/$\rho$b) as the compressive strength of concrete increase.

• Proceedings of the Korea Concrete Institute Conference
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• 1990.04a
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• pp.39-44
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• 1990

This experimental study is performed by using artificial lightweight aggregate manufactured in laboratory, and the test results of it are compared with those using foreign materials in respect of design compressive strength, unit weight. The tests on strength characteristics such as bending, splitting tensile strength and on mechanical characteristics including σ-εcurve, elastic modulus, poisson's ratio are performed to provide the fundamental data required for the design. From this study, it is possible to obtain the high-strength concrete having compressive strength of 500 kg/㎠ and unit weight of 1.85-2.0 t/㎥. And also it is recommended that sandlightweight concrete having high specfic strength is more practical for general use.

• Proceedings of the Korea Concrete Institute Conference
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• 1991.04a
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• pp.54-59
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• 1991

This experimental investigation was aimed at gathering information on the flexural properties, including ductility, of high-strength lightweight concrete members(concrete with a dry unit weight of approximately 1.85t/$\textrm{m}^3$ and with compressive strength approaching 630kg/$\textrm{cm}^2$ at 56days) under reversed cyclic loading. Two sets of six specimens each were manufactured using lightweght aggregate concrete having compressive strength of 350kg/$\textrm{cm}^2$ at 28days and 630kg/$\textrm{cm}^2$ at 56days. The test variables were the concrete strength, the amount of longitudinal reinforcement, and the spacing of ties. The test results, including hysteretic load-deflection curves, for the specimens representing columns under zero axial load are reported in this paper.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.411-414
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• 2005

Concrete structure is recognized as the universal structuring material for its outstanding formability, economic efficiency, and strength development. However, as the ageing of field workers and the deficiency of skilled workers due to evasions from 3D business have recently become the major issues of the industry in Korea and as the materials are becoming more diversified and complicated for today's concrete structures are becoming higher, larger, and specialized, the need for practicality of construction work based on new technology and new method has greatly increased. In other words, the overall condition of today's construction business requires researches and developments on the self-compacting concrete for higher construction efficiency and quality improvements and the high-strength lightweight concrete for concrete weight reduction and reduction of area. Therefore experimental tests were performed as such compressive strength, dry shrinkage and carbonation of self-compacting concrete.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.247-250
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• 2012

As industrialization progresses is rapidly growing, the city of density and temperature is rising successively. It leads to the status of environmental issues. It is needed to develop process of planting concrete block using by Eco-materials for replacing to he existing rooftop light soil that imported. In this study, developing the process of planting lightweight block is researched on using applications of 6 Sigma technique. It makes process object improve standard by using statistical method. Also, there are suggestion that it is optimum mix design conditions and affection of experimental factors in matters of developing planting concrete block for rooftop greening.

• Magazine of the Korean Society of Agricultural Engineers
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• v.41 no.1
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• pp.97-105
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• 1999

Recently , polymer concrete has been widely used in the construction industry because of its quick setting, high strength, excellect adhesion, watertightness and chemical resistance compared to ordinary cement concrete. Its application is also increased. In this paper, lightweight polymer mortars using unsaturated polyester resin and lightweight aggregate are prepared with various mix proportations, and tested for slump working life, apparent specific gravity , flexural and compressive strengths. As a result, the slump and working life can be controlled and thier flexural and compressive strengths are 9.7 to 22.0 MPa , and 23.0 to 100.8 MPa respectively at apparent specific gravities of 0.86 to 1.73.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.157-160
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• 2005

The purpose of this study is to efficiently treat the sewage sludge discharged from sewage treatment plants and evaluate the feasibility of the manufacture of lightweight aggregates(LWA) using a large quantity of sewage sludge and inorganic waste binder ;f1y-ash, waste-stone, tailing, phosphogypsum. Then they were burned in different soak temperatures from 1190$^{circ}C$ to 1290$^{circ}C$ with fixed soak time and heating rate at 5 minutes and 20$^{circ}C$/min respectively in order to produce lightweight aggregate (LWA). Experiment were generated to evaluate the quality of LWA as well as the relationship between burning condition and product's quality.

• Structural Engineering and Mechanics
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• v.57 no.2
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• pp.265-280
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• 2016

A NLFE model was proposed to investigate the mechanical behavior of short columns, cast using plain or fibrous lightweight aggregate concrete (LWAC), and subjected to elevated temperatures of up to $700^{\circ}C$. The model was validated, before its predictions were extended to study the effect of other variables, not studied experimentally. The three-dimensional NLFE model was developed using ANSYS software and involved rational simulation of thermal mechanical behavior of plain and fibrous LWAC as well as longitudinal and lateral steel reinforcement. The prediction from the NLFE model of columns' mechanical behavior, as represented by the stress-strain diagram and its characteristics, compared well with the experimental results. The predictions of the proposed models, considering wide range of lateral reinforcement ratios, confirmed the behaviors observed experimentally and stipulated the importance of steel confinement in preserving post-heating mechanical properties of plain and fibrous LWAC columns, being subjected to high temperature.

• Computers and Concrete
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• v.15 no.5
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• pp.833-845
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• 2015

In the world total boron reserve rating, Turkey is taken place on the first rank, meeting the demand of refined mineral and main boron chemicals. Development of the new boron products and production technologies, spreading the using area of the boron are the study topics which must be finically discussed. In this study, with the help of colemanite taken in ratio as (0%, 7.5%, 12.5%, and 17.5%) by being mixed by the cement, surfaces of the pumice aggregates have been covered. Permeability of the samples has been investigated by producing lightweight concrete with 400 dose with the help of aggregates covered with colemanite. For this, the experiments of water absorption, capillary water absorption, depth of penetration of water under pressure and rapid chloride permeability have been performed. In addition, analyses of the thin section of covered and uncovered pumice aggregates and SEM (Scanning Electron Microscope) have been investigated. When the control samples produced with the covered aggregates and concretes produced with colemanite covered aggregates are compared each other, it has been determined that special lightweight concretes whose values of capillary water absorption experiment, depth of penetration of water under pressure experiment and rapid chloride permeability are low can be produced.