• Computers and Concrete
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• v.32 no.6
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• pp.595-606
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• 2023

Dune sand (DS) has been widely used as a partial replacement for regular sand in concrete construction. Therefore, investigating its mechanical properties is critical for the analysis and design of structural elements using DS as a construction material. This paper presents a comprehensive investigation of the mechanical properties of DS concrete, considering different replacement ratios and strength grades. Regression analysis is utilized to develop strength prediction models for different mechanical properties of DS concrete. The proposed models exhibit high calculation accuracy, with R² values of 0.996, 0.991, 0.982, and 0.989 for cube compressive strength, axial compressive strength, splitting tensile strength, and elastic modulus, respectively, and an error within ±20%. Furthermore, a stress-strain relationship specific to DS concrete is established, showing good agreement with experimental results. Additionally, nonlinear finite element analysis is performed on concrete-filled steel tube columns incorporating DS concrete, utilizing the established stress-strain relationship. The analytical and experimental results exhibit good agreement, confirming the validity of the proposed stress-strain relationship for DS concrete. Therefore, the findings presented in this paper provide valuable references for the design and analysis of structures utilizing DS concrete as a construction material.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.04a
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• pp.26-29
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• 1993

To analyze the using of recycled aggregate on concrete as the substitude aggregate is important problem for the reuse of waste matter and prevention of environmental pollution. Therefore, this study is designed for investigating and analyzing the mechanical properties and early estimational properties of strength on concrete using aggregate of the waste concrete. And is aimed to provide the fundamental data for recycled aggregate.

• Journal of the Korean Society of Safety
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• v.16 no.1
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• pp.43-47
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• 2001

Effect of coupling agent on the mechanical properties of PP/GF blend was investigated. The flexural modulus, Izod impact strength, elongation at yield and tensile strength were improved with using coupling agent. Mopological studies revealed that PP and GF were incompatible and addition of coupling agent was very effective to enhance the compatibility, result in mechanical properties.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.419-424
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• 2000

The primary objectives of this study are to investigate the properties of strength and durability of recycled aggregate concrete was added polypropylene as variables and to fabricate fine concrete in some conditions. The variables are substitution ratios of recycled aggregate(0, 30, 50, 100%) and additions of polypropylene(0, 0.2, 0.5, 1.0%). Compressive strength test to investigate strength properties and freeze-thawing test and drying shrinkage test to durability properties were done. As the result of this study, When variables are substitution ratio(30%) of recycled aggregated and addition(0.5%) of polypropylene, fine concrete was fabricated.

• Proceedings of the KWS Conference
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• 2007.11a
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• pp.168-170
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• 2007

Sn-Bi eutectic solder alloy have is good wetting and physical properties. The results of solder paste properties test, melting point is about $139^{\circ}C$ and spread test is represent spread properties of $7{\sim}16%$. The results of shear strength after as reflowed, thermal shock test, high temperature storage test of 500hr and 1000hr at $100^{\circ}C$. The shear strength value range is from 6000 to 11000gf, pull strength value range is from 2200 to 3300gf.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.10a
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• pp.321-327
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• 1996

The result of an experimental study on the mechanical properties of different types of polypropylene fiber reinforced concrete are presented in this paper. This study has been performed to obtain the properties of PFRC such as slump, Vee-Bee time, compressive strength, tensile strength, flexural strength, toughness and resistance to impact. The test variables are fiber content, fiber types, fiber length and W/C ratio. Polypropylene fibers were effective in reinforcing the matrix. A remarkable increase in toughness was observed by the addition of polypropylene fibers.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.204-207
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• 2004

In this paper, mechanical properties of the high strength lightweight self-compacting concrete with simple mixed design method was investigated. Experimental tests were performed as such compressive strength, splitting tensile strength, modulus of elasticity and density of high strength lightweight self-compacting concrete. The 28 days compressive strength of high strength lightweight self-compacting concrete with the LC replacement ratio of $100\%$ reduces about $31\%$ but LF replacement ratio of $100\%$ increase about $20\%$ compared that of the control concrete. The structural efficiency of high strength lightweight self-compacting concrete increase with proportional to the replacement into of LF. The relationship between the splitting tensile strength and 28 days compressive strength can be represented by the equation $f_s=0.076f_{ck}+0.5582$. The modulus of elasticity was found to be lower than that of normal weight concrete, ranging form 24 to 33 GPa.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.26-27
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• 2014

Study on high temperature properties of concrete and internal force estimation of structural member subjected to high temperature mainly applied high temperature strength model based on experimental results with concrete under 40MPa. However, it is reported that degradation of internal force at high temperature and spalling of ultra high strength concrete are higher than that of normal strength concrete. Therefore, this study attempts to propose compressive strength degradation model which is suitable to ultra high strength concrete comparing to existing model by evaluating high temperature properties of ultra high strength concrete.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.657-660
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• 2008

The mechanical properties of concrete such as compressive strength, tensile strength, and modulus of elasticity, are considerably influenced by various factors including locality. The material property prescriptions in national concrete design codes should reflect them. In Korea, they have not been studied systematically yet. A new performance-based design code is being prepared in Korea as a government-supported project and it has a plan to make new material prescriptions adopting domestic research results. As a starting point for the research on material properties, the statistical characteristics of mechanical properties of concrete are studied. In this paper, a probabilistic model of compressive strength, relationship between compressive strength and splitting tensile strength and compressive strength and elastic modulus are proposed based on experimental data.

• Journal of the Korean Society for Heat Treatment
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• v.26 no.1
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• pp.7-13
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• 2013

Vacuum heat treatment(indirect heating method) has long exposure time at high temperature and low quenching rate. Contrarily salt bath heat treatment (direct heating method) has short exposure time at high temperature and fast cooling rate. With these different features of processes, mechanical properties such as hardness, tensile strength and impact strength of products show very different results. In this study, Salt bath heat treated products showed higher tensile strength and impact strength than vacuum heat treated products but hardness was not much different. These lower mechanical properties of vacuum heat treated products are due to differences in heat process and secondary hardening with high temperature tempering process. Consequently, It indicates that salt bath heat treatment is better way than vacuum heat treatment for product to have high mechanical properties.