• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.11a
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• pp.73-77
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• 2008

Structural lightweight concrete will reduced total loads of supporting sections and foundations in archtectural and civil structures. So, the lightweight concrete can be used widely for various purpose in the archtectural and civil structures. This paper were examined the influence of the mixing factor on the fresh and hardened properties of lightweight concrete that are used 2types of the differences properties of lightweight aggregates. According to types of lightweight aggregates, the case of synthetic lightweight aggregate are have need higher s/a; 2~4% on mixing proportion. Lightweight concrete was somewhat exhibit lower compressive strength than ordinary concrete. However it was not showed a marked difference. According to types of lightweight aggregates, the case of synthetic the lightweight aggregate are highest performance in fresh and hardened concrete.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.3
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• pp.77-84
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• 2012

It is known that some components of wood obstruct the hydration of cement when wood is mixed with cement. In order to examine the effect of pretreatment of wood chips in hot water, this study conducted the experiments for the setting and compressive strength of mortar by sieving pine wood chips with a 2.4mm sieve, dipping them in waters of different temperatures, and then using them as a part of the fine aggregate. For the experiments, water-cement ratio of the mortar was 0.50 and the amount of the fine aggregate substituted by wood chips was set at 0%, 2%, 4%, 6%, 8%, and 10% of the mass of the fine aggregate. As a result of the test, it was found out that when wood chips were used to substitute fine aggregate for the production of mortar, more usage of wood chips postponed setting more, and the treatment of wood chips with water improved the problem of the delay in setting time. Especially, the final setting time of the mortar which used 2~6% of wood chips treated in $100^{\circ}C$ water for 30 minutes was almost the same as the final setting time of the mortar which used no wood chips. Also, the compressive strength of the mortar which used the wood chips treated with water was compared to that of the mortar which used the wood chips not treated with water. The result showed that the strength improved for age of 7 days and 28 days, while there was little change in strength for age of 3 days.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.103-104
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• 2012

Lately, minimize of the heat loss and fuel consumption when heating so that suggested ways to reduce carbon emissions as a measures to reduce for increase of carbon emission and find a way to apply highly insulated concrete as the measures. In this study, as a comparative experiments on heat conduction of concrete with lots of porous, thermal conductivity of concrete using foamed, polystyrene beads, lightweight aggregates, air-entraining agent and concrete using crushed stone measure and thermal conductivity of concrete with lots of porous compare and evaluate.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.11a
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• pp.113-116
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• 2008

In these days, properties of concrete has been demanded to be high performance because concrete structure was bigger and higher. So studies on high strength concrete and lightweight concrete has been frequently done. But lightweight concrete has been used to limited non-structural elements in th country. Lightweight aggregate mixed with lightweight concrete was only coarse aggregate in case of the structural lightweight concrete. In the country studies on the lightweight concrete was poor and unvaried. Also it is difficult to be practical use of lightweight concrete was that it has been expensive. It was study on the using fine lightweight aggregate with lightweight concrete to crushed by-products and wastes to get to make foamed glass with recycled glass. So it was tested by fine aggregate standard and mixed with.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.452-459
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• 2017

In recent years, to reduce self-weight of structural elements, the use of SCP (Steel Concrete Plate) instead of prestressed concrete is increasing. Because SCP has a complicated sectional shape and includes a large number of studs, the use of high-fluidity concrete is required. Therefore, in this study, to prevent the restrained shrinkage behavior by the stud, the effects of using an expansive agent (EA) and shrinkage reducing agent (SRA) were investigated, and the optimal mixture proportions to maximize the filling capacity were determined based on the fine aggregate ratio. The test results indicated that the combined use of EA and SRA exhibited the smallest shrinkage. The ratio of the crushed sand and washed sea sand was determined to be 5:5, and the proper fine aggregate ratio was found to be 55.6%, because when the ratio was too high, a decrease in strength and an increase in shrinkage strain were expected. The high-fluidity concrete effectively filled the large-sized SCP module.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.2
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• pp.84-90
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• 2012

Patents in Korea, Japan and the U.S. were searched at the Korea Intellectual Property Rights Information Service (KIPRIS) of Korea Institute of Patent Information using related keywords in order to analyze the trend of patents on the usage of waste wood. Materials on a total of 77 patents in Korea, 317 patents in Japan, and 316 patents in the U.S. that had been registered as patents as of Dec. 31, 2011 were collected. Among the collected materials, the patents rejected, expired, annulled, withdrawn and waived as well as those which had little relationship with waste wood were excluded and the 71 patents in Korea, 227 patents in Japan and 216 patents in the U.S. were finally selected for analysis. In addition, the properties of the mortar which used waste wood as an alternative for a part of the fine aggregate were tested as a basic study for the usage of waste wood as a lightweight aggregate for concrete. For the test, the waste wood of the pine tree was crushed, sifted through No. 8(2.4 mm) sieve, and then dried for 24 hours at $100{\pm}5^{\circ}C$. As it is known that some kinds of tree prevent the hardening of cement when the wood is mixed with cement, the crushed waste wood in this study was dipped in the water of $20^{\circ}C$, $50^{\circ}C$, $80^{\circ}C$ and $100^{\circ}C$ and then dried up before testing the properties of the mortar to examine the effect of the preliminary treatment of crushed waste wood.

• Journal of the Korea Institute of Building Construction
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• v.7 no.1 s.23
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• pp.115-121
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• 2007

Ordinary concrete uses aggregate sufficiently soaked with water, and is weighed, mixed with other materials and placed in accord with performances required in the construction field. Recently special concrete with high fluidity and durability is required but it is difficult to use top-quality concrete due to lack of high-quality aggregate, delayed transportation because of traffic jam, etc. In addition, sometimes the use of a remicon is inevitable just for small-sized concrete constructions or it is difficult for a remicon to reach remote construction places such as mountainous areas. To solve these problems, this study attempted to pack concrete materials. In other words, it is to instantize concrete. This study dried aggregate, a material of concrete, and compared the change of absorption phase of the aggregate in water and in paste in order to examine the effect of the dryness of aggregate on its absorption rate and, based on the absorption rate, decided water addition ratio necessary for the reduction of unit quantity caused by the use of dry aggregate in designing concrete mixture, and analyzed the properties of unhardened concrete according to water addition ratio in manufacturing concrete using aggregate in the state of absolute dryness and in the state of surface dryness.

• Journal of the Korea Concrete Institute
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• v.14 no.4
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• pp.540-548
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• 2002

The purpose of this study is to analyze the application of oyster shells (OS) as aggregates for concrete. For this purpose, five reference mixes with W/C ratios of 0.4 ∼0.6 at intervals of 0.05 were used. The replacement proportion of OS was varied with ratios of 0, 10, 30, 50 and 100％ by volume of fine or coarse aggregate in the reference mixes. OS was washed and crushed for using as aggregates. New chemical reaction between crushed OS aggregate and cement paste was tested through XRD and SEM analysis. Two strength properties (compressive and flexural) were considered. Strength tests were carried out at the ages of 1, 3, 7, 14 and 28 days. The variations of workability, air content and density, drying shrinkage of the specimens with different proportions of OS were also studied. Finally, the hollow concrete block using OS as a substitute material for fine aggregate was made for testing the application of OS. Experimental results showed that my new chemical reaction did not occur due to mixing OS in concrete. The workability and strengths decreased with increase in proportion of OS. The same trend was observed in density and unit weight, but air content increased due to the inherent pores in OS, which showed a possibility to produce light weight concrete with low strength by using OS as coarse aggregates for concrete. Tests on hollow concrete block showed that the compressive strength and absorption ratio were satisfied with quality requirements when the fine aggregate was substituted with OS up to 50％ in volume.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.781-784
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• 2006

This paper investigates the fundamental properties of light weight foamed concrete with the variances in unit weight of concrete and adding ratio of stability agent(SA). Test showed that concrete adding SA slightly decreased fluidity but secured stable flow appearances without segregation of concrete components. All specimens in a standard condition represented that a sinking depth was not observed, while, in the wet condition, a specimen adding SA decreased the sinking depth $2{\sim}4mm$ more than control concrete. Compressive strength values of control concrete showed $0.03{\sim}0.3MPa$ higher than the concrete adding SA. As for the tensile strength, the specimen adding SA also had lower value, while the ratios of comp. to tens. strength presented $0.43{\sim}0.62$, which is relatively higher than ordinary concrete.

• Journal of the Korea Concrete Institute
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• v.21 no.3
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• pp.283-290
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• 2009

Differently from fly ash, the bottom ash produced from thermoelectric power plant has been treated as an industrial waste matter, and almost reclaimed a tract from the sea. If this waste material is applicable to foam concrete as an aggregate owing to its light-weight, however, it may be worthy of environmental preservation by recycling of waste material as well as reducing self-weight of high-rising structure and horizontal forces and deformations of retaining wall subject to soil pressure. This study has an objective of evaluating the effects of application of bottom ash on the mechanical properties of foam concrete. Thus, the ratio of bottom ash to cement was selected as a variable for experiment and the effect was measured in terms of unit weight of concrete, air content, water-cement ratio and compressive strength. It can be observed from experiments that the application ratios have different effects on the material parameters considered in this experiment, thus major relationships between application ratio and each material parameter were finally introduced. The result of this study can be applied to decide a mix design proportion of foam concrete while bottom ash is used as an aggregate of the concrete.