• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.05a
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• pp.19-22
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• 2006

The quantity of Recycled concrete powder is increased, because it hal been ever so often crushing for production of a good quality recycled aggregates This Study is on the Development of Concrete-Product by Using Recycled Concrete Powder and alto for know performance of concrete-producted having low water contents and it is to know for all of performance of concrete-producted having low water contents The conclusions of this study are following. The use of replacement cement is not effective, because it has strengh of less than 10MPa But It is possible to develop high strength concrete-producted having 39MPa above compressive strength by using recycled concrete powder. Because strength enhancement effects by recycled concrete powder are responsible to optimum grading. The conclusions of this study are following. The use of replacement cement is not effective, because it has strengh of less than 10MPa. It is possible to develop high strength concrete-producted having 39MPa above compressive strength by using recycled concrete powder. Because strength enhancement effects by recycled concrete powder are responsible to optimum grading.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.04a
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• pp.172-179
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• 1996

Recently, the broken concrete lumps resulting from the demolition of concrete structures are creshed for reuse as aggregates(i.e. recycled fine and gravel). And also, in the processing of crusing, the recycled powder of an equivalent of between 20% to 30% by wt.% of the broken concrete lumps is generated. The extensive research of recycled concrete aggregates has been carried out in various parts of the world. But less reseatch on the reuse of recycled concrete powder has been carried out. It is the purpose of this report that the study on the quality evaluation of recycled aggregates for recycled concrete. In specially, this report deals with the properties such as flow, compressive strength, bending strength, drying shrinkage and wight loss rate of mortars replaced standard fine aggregate with recycled powders at the rate of 3, 7, 15, 20 and 30 wt.%. Since the characteristics of recycled mortars with the recycled powders were comparable to those of the normal mortar without the recycled powders as described above, its concretes could be found extensive application in such field as concrete products.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.521-524
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• 2006

This study is about the production and properties of waste concrete powder that recycling aggregate is crushed to the waste concrete. We researched the generation and the disposal of recycled concrete powder. It is chemica] and physical features that is compared and analysis according to its production system and repeated crushing of time. Recycled concrete powder is more generated wet process than drying process. In addition, the more it is repeated crushing of time, the more recycled concrete powder is generated. Recycled concrete powder is discovered that wet process is larger of the specific area, lower density and particle size.

• Journal of the Korean Society of Safety
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• v.25 no.2
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• pp.41-46
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• 2010

This is to show some basic data for introducing both circulated aggregate and recycled powder producing waste concrete. Standard-mixing design for 24MPa has been basically used and added and replaced normal aggregate with recycled powder made of waste concrete. In addition, polycarboxylate high-range water reducing agent has been used because recycled powder is missing adhesive strength and it is not compare with cement's adhesive strength. Compressive strength with powder mixture of 2%, 4%, 6%, 8%, and 10% has been decreased down to 80% of normal concrete material strength without recycled powder mixture. This result has same decreasing proportion to tensile strength of the material. Resistant capacity change of beam varying with recycled powder mixture has been decreased down to 60% of normal concrete bean capacity, while there are 80% decrease of material strength. But strength and capacity change has same consistent decrease ratio. It is found that recycled powder with approximately 15% unit concrete volume can be replaced with cement in reasonable admixture mixing condition.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.05a
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• pp.61-64
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• 2005

Recently, there have been many studies about recycling cementitious powder from concrete waste(hereinafter referred to as waste powder), generated after recycle aggregate production. Previous studies showed that when the heating process of waste powder at $700^{\circ}C,\;Ca(OH)_2$ in paste is dehydrated making possible the restoration of hydraulic properties. Recycled cement with hydraulic properties restored is thought to be re-hydrated through the mechanism of hydration, which is almost similar in Portland cement. This clearly suggests that the hydrate of recycled cement is alkali in type. Like in general concrete, if recycled cement is used as a structural material, resistance performance against carbonation or neutralization by $CaCO_3$ in air probably would be most influential to the life of steel-reinforced concrete structure. Thus the purpose of this study is to make an experimental review on chemical properties of recycled cement, manufactured with concrete waste as base material, and investigate the durability of concrete using recycled cement through evaluating the cement s performance of resistance to carbonation in accordance with its accelerating age. Based on its results, further, the study seeks to provide basic information about ways of utilizing recycled cement.

• Journal of the Korea Institute of Building Construction
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• v.6 no.4 s.22
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• pp.61-68
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• 2006

Recently, there have been many studies about recycling cementitious powder from concrete waste(hereinafter referred to as waste powder), generated after recycle aggregate production. Previous studies showed that when the heating process of waste powder at $700^{\circ}C,\;Ca(OH)_2$ in paste is dehydrated making possible the restoration of hydraulic properties. Recycled cement with hydraulic properties restored is thought to be re-hydrated through the mechanism of hydration, which is almost similar in Portland cement. This clearly suggests that the hydrate of recycled cement is alkali in type. Like in general concrete, if recycled cement is used as a structural material, resistance performance against carbonation or neutralization by $CaCO_3$ in air probably would be most influential to the life of steel-reinforced concrete structure. Thus the purpose of this study is to make an experimental review on chemical properties of recycled cement, manufactured with concrete waste as base material, and investigate the durability of concrete using recycled cement through evaluating the cement's performance of resistance to carbonation in accordance with its accelerating age. Based on its results, further, the study seeks to provide basic information about ways of utilizing recycled cement.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.635-640
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• 2001

Recently, it has been processed to study about recycled aggregate but a study about using of recycled powder is producted when manufacturing recycled aggregate has not been acted. So in this study on the fundamental properties and application as cementious admixture by heating temperature for mortar properties of recycled powder and sand is obtained like following results. It is judged that application of recycled powder of heat treatment on $600^{\circ}C$ and cement replacement ratio below 10% is available.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.11a
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• pp.39-40
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• 2011

This study is to analyse possibility cementitious powder from waste concrete as row material of recycled cement. From the results, we ascertained possibility as recycled cement through XRF & XRD of cementitious powder & recycled cement. As a result of the experiment, cementitious powder from waste concrete, which appeared to recovery hydration chemically at the calcining temperature of 700, suggested highly possibility as recycled cement.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.252-253
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• 2014

This study is to XRD and image analysis of low carbon type recycled cement from waste concrete powder and cement raw materials. Waste concrete powder possible to low carbon type recycled cement in small part of additive materials. Also, low carbon type recycled cement using waste concrete powder is suitable for ordinary portland cement.

• Journal of the Korean Society of Marine Environment & Safety
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• v.14 no.4
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• pp.289-295
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• 2008

The disposal of constructive waste is emerging as a national and social issue and the recycled powder generated by the production of reproductive aggregate is all being abolished or buried Analysis on the harmful effect of recycled powder indicated that because it contained massive cytotoxicity, it could derive secondary pollution to soil and subterranean water. This study set on an idea that one way to recycle recycled powder was to use it as a compound of concrete. In order to study that prospect, recycled powder, instead of cement, was mixed and a comparative analysis was conducted on the mechanical properties and workability. From experimental results, it was judged that application of recycled powder of cement replacement ratio below 20% was available with chemical admixtures. Also application of recycled powder was available to high strength concrete.