• Advances in concrete construction
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• v.2 no.4
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• pp.249-259
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• 2014

Mortar is a masonry product which is matrix of concrete. It consists of binder and fine aggregate and moreover, it is an essential associate in any reinforced structural construction. The strength of mortar is a special concern to the engineer because mortar is responsible to give protection in the outer part of the structure as well as at a brick joint in masonry wall system. The purpose of this research is to investigate the compressive strength and tensile strength of mortar, which are important mechanical properties, by replacing the cement and sand by stone dust. Moreover, to minimize the increasing demand of cement and sand, checking of appropriateness of stone dust as a construction material is necessary to ensure both solid waste minimization and recovery by exchanging stone dust with cement and sand. Stone dust passing by No. 200 sieve, is used as cement replacing material and retained by No. 100 sieve is used for sand replacement. Sand was replaced by stone dust of 15%, 20%, 25%, 30%, 35%, 40%, 45% and 50% by weight of sand while cement was replaced by stone dust of 3%, 5%, and 7% by weight of cement. Test result indicates that, compressive strength of specimen mix with 35% of sand replacing stone dust and 3% of cement replacing stone dust increases 21.33% and 22.76% respectively than the normal mortar specimen at 7 and 28 days while for tensile it increases up to 13.47%. At the end, optimum dose was selected and crack analysis as well as discussion also included.

• Journal of the Korean Geotechnical Society
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• v.24 no.10
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• pp.5-15
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• 2008

The purpose of this study is to examine the validity of recycled aggregates (RAs) as a substitute for Sand-Mat material for soft ground improvement in the housing site development. To evaluate the possibility of RAs as a substitute for sand mat material, first of all, the criteria and regulations related with the quality of lateral drain layer were collected and checked. Secondly, both of the properties of RAs were compared with the properties of natural sand for the lateral drain layer. The material properties related to coefficient of permeability, pressure at-rest state and so on satisfied most standards. On the basis of the test results, RAs were used to the construction site as lateral drain layer. Accordingly, if the quality of RAs can be managed well, the application of these RAs as lateral drain layer to replace natural sand was highly effective. Also, based on cost analysis of two materials, RAs are proved to be very competitive.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.116-119
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• 2003

The Natural aggregate will be faced with serious shortage problem within 10 years due to the great amount of consumption in domestic. In order to reserve our natural resources, the construction waste has to be reused as an alternative material. Especially, It is more imminent to find alternative material in case of fine aggregate. This paper presents and experimental results on the fundamental property of concrete using recycled fine aggregate. As a result, it was found that the property of concrete using recycled fine aggregate substituted for 25% of a natural sand was similar in that of crushed fine aggregate.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1390-1395
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• 2005

To analyze the effects of oyster shell particles, inserted in the self-hardening matrix such as cement paste, on strength, homogenization analysis using micro structure was used to estimate and assess the apparent elastic modulus of oyster shell particle. DIB modeling technique was used to represent of the micro structure of oyster shell mixed concrete. The results showed that the apparent elastic modulus of LOS (large oyster shell particle) was changed with the amount of LOS inserted. In particular, when the amount of LOS was 200% of the weight of cement, the apparent elastic modulus of LOS tended to decrease rapidly. This could mean that the strength of oyster shell mixed concrete is much affected by LOS inserted material in mixed ratio of 200%.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.729-732
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• 2006

Portland cement is presently the most widely used construction material. The process of manufacture of cement consists essentially of grinding the raw materials, mixing them intimately proportions and burning in a rotary kiln at a temperature of up to about $1450^{\circ}C$. Raw materials have used limestone, clay, silica, and iron oxide and fuel have used bituminous coal. Recently, A standpoint of the recycling of material resources, the production of cement use of industrial waste and residual products. Therefore, the final product of cement were included heavy metals such as $Cr^{+6}$ and Pb. The purpose of this study is standardization for $Cr^{+6}$ analysis in cement and concrete. From the comparative study of the examination method of $Cr^{+6}$ analysis, Japan cement association standard of $Cr^{+6}$ analysis is most suitable for the real state of affairs in korea.

• Earthquakes and Structures
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• v.23 no.6
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• pp.493-502
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• 2022

In recent decades, infrastructural development has exploded, particularly in the coastal region of Saudi Arabia. The rising demand of most consumed aggregate in construction can be effectively compensated by the alternative material like scoria which lavishly exists in the western region. Scoria is characterized as lightweight aggregate beneficially used to develop lightweight concrete (LWC) - a potential alternative of normal weight concrete (NWC) ensuring reduction in the structural element's size, increase in building height, comparatively lighter foundation, etc. Hence, the goal of this study is to incorporate scoria-based structural lightweight concrete and evaluate its impact on superstructure and foundation design beside contributing to the economy of construction. Fresh, mechanical, and rheological properties of the novel LWC have been investigated. The structural analyses employ the NWC as well as LWC based structures under seismic and wind loadings. The commercial finite element package - ETABS was employed to find out the change in structural responses and foundations. The cost estimation and SWOT analysis for superstructure and foundation have also been carried out. It was revealed that the developed LWC enabled a more flexible structural design. Notable reduction in the steel and concrete prices of LWC might be possible in the low-rise building. It is postulated that the cost-effective and eco-friendly LWC will promote the usage of scoria as an effective alternative in Saudi Arabia and GCC countries for structurally viable LWC construction.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.4
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• pp.324-330
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• 2018

In accordance with the amendment of the Industrial Safety and Health Act of 2007, Korea completely prohibited the import, distribution and manufacture of asbestos like Europe and Japan. Accordingly, the current problem of asbestos is the safe maintenance and disposal of asbestos construction material, the disposal of asbestos, and the final disposal of asbestos building materials. In the past, Korea used 100,000 tons of asbestos every year, and the building materials using it exceeded 1 million tons per year. These asbestos building materials continued to be used until 2006, and the Ministry predicted that these materials would continue to be maintained until 2044. When the permeable hardening agent is applied to the asbestos building material installed in the pre-pretreatment step for the harmless treatment of the asbestos waste and the dismantling is carried out, the scattering of the asbestos is suppressed in the disassembling step, detoxification treatment conditions can be improved. Therefore, permeable hardeners should be stably penetrated into asbestos building materials. In this study, it is suggested that pre - pretreatment methods for the harmlessization of waste asbestos building materials with medium density level can be presented. In order to efficiently perform pre - treatment for chemical harmlessness in the future, the mixing ratio of permeable hardener and middle water Optimization is the most important factor.

• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.4
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• pp.291-296
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• 2014

For the purpose of energy consumption and green-house gas reduction from building, new insulation materials with improved thermal property have been developed and used. Among new insulation materials, mineral hydrate which compensates for the defects of existing materials is using as a prominent insulation material. The fabrication method of mineral hydrate is similar to that of ALC for building structure but mineral hydrate is only used for insulation. The raw materials that make up of mineral hydrate are cement, lime and anhydrite. Especially anhydrite is all dependant on imports. In this study, Desulfurization Gypsum(DG), by-product of oil plant, was used for replacing for imported anhydrite and waste recycling. DG substituted all of anhydrite and a part of lime. Mineral hydrate used DG had analogous thermal and physical properties, compared to existing mineral hydrate.

• Journal of the Korea Institute of Building Construction
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• v.9 no.4
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• pp.131-137
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• 2009

The rate of recycling of waste concrete, which represents the majority of construction-related waste, is increasing. However, a general recognition of the inferior qualify of recycled aggregates and their lower grade of compressive strength, bending strength, shear strength, frost resistance and ductility make the application of recycled aggregates to structures insufficient. Therefore, this study conducted material and member experiments by adding steel fiber for the purpose of improving the properties of recycled aggregate concrete. To synthesize the experimental results, it was found that specimens with a 30% steel fiber admixture had levels of compressive strength, tensile strength and frost resistance that were equivalent to or higher than the standard specimen, and that concrete that had a 30% replacement of recycled aggregates with steel fiber was suitable for application to actual structures.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.729-732
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• 2008

Complexity and Massive is the modem trend of construction project. The lack of timely and accurate construction data is the main cause for the lack productivity increases seen in other industries. Because information is essential in the construction production process, the lack of it will cause workers to stay idle, build the wrong thing that has to be redone, become involved in an accident or simply waste their time doing non-productive work. To aid construction automation and improve its productivity, RFID technology system should be developed. As a result of that, this study analyzes the status of RFID technologies in construction project and suggest advanced construction method. USN and RTLS system is analyzed in this study RFID system also can be used in construction management, material management, quality control, safety management and human resource management.