• 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 Korea Concrete Institute Conference
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• 1995.04a
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• pp.177-182
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• 1995

Large-scaling recycling of demolished concrete will contribute not only to the solution of a growing waste disposal problem. it will also help to conserve natural resoures of sand and gravel and to secure future supply of reasonly priced aggregates for builiding and other construction purposes within large urban areas. because recycled aggregate particles consist of substaintial amount of relatively soft cement paste component, it is less resistant to mechanical actions. With this view in mind, to obtain a reference data for the development of recycling system and to a basic data the guideline of recycled aggregate concrete construction and mix design, this study deals with the comparative analysis of the workability and engineering properties of recycled aggregate concrete according to the factors, such as blending ratio of recycled aggregate with the natural aggregate, addition of flyash, water cement ration.

• Journal of The Korean Society of Agricultural Engineers
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• v.58 no.3
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• pp.21-27
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• 2016

This study was performed to evaluate engineering properties of carbon and glass fiber reinforced recycled polymer concrete. Fiber reinforced recycled polymer concrete were used recycled aggregate as coarse aggregate, natural aggregate as fine aggregate, $CaCO_3$ as filler, unsaturated polyester resin as binder, and carbon and glass fiber as fibers. The compressive and flexural strength of carbon fiber reinforced recycled polymer concrete were in the range of 68~81.5 MPa and 19.1~21.5 MPa at the curing 7days. Also, the compressive and flexural strength of glass fiber reinforced recycled polymer concrete were in the range of 69.4~85.1 MPa and 19~20.1 MPa at the curing 7days. Abrasion ratio of carbon and glass fiber reinforced recycled polymer concrete were decreased 21.6 % and 11.6 % by fiber content 0.9 %, respectively. After impact resistance test, drop numbers of initial and final fracture were increased with increase of fiber contents. Accordingly, carbon fiber and glass fiber reinforced recycled polymer concrete will greatly improve the hydraulic structures, underground utilities and agricultural structures.

• Resources Recycling
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• v.18 no.3
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• pp.20-26
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• 2009

The objective of this study is to investigate the properties of fresh concrete with recycled coarse and fine aggregates. Four different kinds of aggregate with natural, recycled aggregates were prepared. The concrete mixtures were produced with test parameters of replacement ratio of recycled aggregate. The properties of the fresh concrete were measured by means of slump and air content according to elapsed time. Quality control method to maintain the constant total mixing water for recycled aggregate concrete was suggested. The all concrete mixtures were produced with approximately the same slump on the job site after an hour. Test results indicated that compressive strength of concrete with constant slump is not affected by the replacement ratio of recycled aggregate. Also the practical way for the quality control of recycled aggregate concrete is to maintain the constant total mixing water.

• Journal of the Korea Concrete Institute
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• v.17 no.4 s.88
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• pp.613-620
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• 2005

There are some problems in utilizing recycled concrete aggregate go structural use because of the difficulties concerning about quality control and durability. It seems to be possible to utilize recycled concrete aggregate for making concrete products because quality control of concrete products is easier than ready-mixed concrete, but there are little studies about the properties of the steam-cured recycled aggregate concrete. In this study, various tests were performed such as compressive strength, flexural strength, splitting tensile strength, bonding strength and chloride ion penetration test to evaluate the effect of substitution of recycled concrete aggregate. The results of strength test showed that the concrete strength decreased with the increase of the substitution ratio of recycled concrete aggregate, but it was in the reasonable range and almost equal to that of normal concrete below the substitution ratio of $50\%$. On the other hand, strength test of furnace slag cement concrete shows that the strength of recycled concrete with furnace slag cement under curing condition lower than that of recycled concrete with ordinary portland cement under same condition. From the result of this study, it can be concluded that recycled concrete aggregate is able to be utilized for structural use but substitution ratio should be decided with care in each case. The result of this study could be used as the basic data for the structural use of recycled concrete aggregate.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.473-476
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• 2008

The use of the recycled fine aggregate to the material of structural concrete is not easy currently because there are some problems, such as the difficulty of quality control and the badness of chemical and physical property other than river sand, crushed fine aggregate. To use of recycled fine aggregate, many researches on the recycling of recycled fine aggregate have been studying until today. However, the result of the research is little except for some results. Therefore, the purpose of this study is to confirm the possibility of use of recycled fine aggregate for raw material of plaster mortar. In this study, various tests were performed such as flow, air content, unit weight, bond strength, and compressive strength test to evaluate the effect according to the substitution of recycled concrete aggregate. The results of strength test showed that the concrete strength improved with the increase of replacement ratio of recycled fine aggregate. In the other side, flow and air content are decreased according to replacement ratio of recycled fine aggregate. The result of this study could be used as the basic data for the recycling of recycled fine aggregate.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.521-526
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• 2000

The structural behavior of the members using recycled coarse aggregate is investigated in this papers. The members considered this study are subjected to shear ad bending simultaneously. A series of test beam specimens using recycled coarse aggregate is made for the structural test. These specimens are manufactured using the concrete for the compressive strength of 280kg/$\textrm{cm}^2$ with recycled aggregate ratio of 0%, 20%, 40%, 60%, 80% of total aggregate volume, respectively. The main object of this test is to investigate the influence of the using recycled aggregate to the cracking strength of the member subjected to flexure and shear and the post cracking behavior.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.437-440
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• 2005

The effects of polymer-cement ratio and recycled aggregate content on the continuous void ratio, coefficient of permeablity, compressvie, tensile and flexural strengths of water-permeable polymer-modified concretes using recycled aggregate are examined. As a result, the continuous void ratio and coefficient of permeablity of the water-permeable polymer-modified concretes tend to decrease with increasing polymer-binder ratio. Regardless of the recycled aggregate content, the compressvie, tensile and flexural strengths of the water-permeable polymer-modified concretes wtend to increase with increasing polymer-cement ratio.

• Steel and Composite Structures
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• v.9 no.1
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• pp.19-38
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• 2009

The present paper provides test data to evaluate the seismic performance of recycled aggregate concrete (RAC) filled steel square hollow section (SHS) beam-columns. Fifteen specimens, including 12 RAC filled steel tubular (RACFST) columns and 3 reference conventional concrete filled steel tubular (CFST) columns, were tested under reversed cyclic flexural loading while subjected to constant axially compressive load. The test parameters include: (1) axial load level (n), from 0.05 to 0.47; and (2) recycled coarse aggregate replacement ratio (r), from 0 to 50%. It was found that, generally, the seismic performance of RACFST columns was similar to that of the reference conventional CFST columns, and RACFST columns exhibited high levels of bearing capacity and ductility. Comparisons are made with predicted RACFST beam-column bearing capacities and flexural stiffness using current design codes. A theoretical model for conventional CFST beam-columns is employed in this paper for square RACFST beam-columns. The predicted load versus deformation hysteretic curves are found to exhibit satisfactory agreement with test results.

• Journal of the Korean Society of Hazard Mitigation
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• v.5 no.1 s.16
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• pp.77-84
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• 2005

Amount of demolished concretes is highly produced as dismantlement of structures to increased owing to usage alteration and deteriorated of concrete structures, but most of them have been used as material for simple reclamation. Therefore, if demolished concrete could be recycled as aggregate for concrete. it will contribute to solve the exhaustion of nature aggregate, in terms of saving resources and protecting environment, especially being want of resources in Korea. In this study it was investigated into experimental results that were carried out demolished concrete recycled aggregate gained from dismantled real structures and source concrete recycled aggregate produced according to respectively 5 steps of replacement ratio for recycling as pavement concrete aggregate.