• Title/Summary/Keyword: cementitious powder from waste concrete

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Recycling Technology of Cementitious Powder for Completely Recycling of Concrete Waste (폐콘크리트의 순환이용을 위한 폐미분말의 재활용 기술)

  • Park, Cha-Won;Kang, Byeung-Hee
    • Journal of the Korea Institute of Building Construction
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    • v.5 no.3 s.17
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    • pp.109-116
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    • 2005
  • Recently, there have been many studies seeking towards the utilization of cementitious powder from concrete waste as recycled cement. However, most of the studies actually have been researches about the reuse of mortar or paste, not concrete waste. In fact, either mortar or paste is quite different from a real concrete waste in terms of age and mixture. Thus the purpose of this study is to examine basic physical properties of recycled cement, manufactured with cementitious powder from concrete waste, and analyze differences in chemical and hydraulic properties of the cement and its tested model. As a result of the chemical analysis, recycle cement is composed mainly of CaO and $SiO_2$, and that it is even lower in the content of CaO than Portland cement, which is also supported by previous studies. But, Differently from previous studies, calcining temperature of 650 was found an optimal condition under which cementitious powder from concrete waste could restore its hydraulic properties.

Hydraulic Properties of the Recycled Cement used Cementitious Powder by Concrete Waste (폐콘크리트 부산 미분말을 이용한 재생시멘트의 수화특성)

  • Xu Jing-Hao;Park Cha-Won;Ahn Jae-Cheol;Kang Byeung-Hee
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2005.05a
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    • pp.69-72
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    • 2005
  • Recently, there have been many studies seeking towards the utilization of cementitious powder from concrete waste as recycle cement. However, most of the studies actually have been researches about the reuse of mortar or paste, not concrete waste. In fact, either mortar or paste is quite different from a real concrete waste in terms of age and mixture. Thus the purpose of this study is to examine basic physical properties of recycle cement, manufactured with cementitious powder from concrete waste, and analyze differences in chemical and hydraulic properties of the cement and its tested model. As a result of the chemicai analysis, recycle cement is composed mainly of CaO and SiO2, and that it is even lower in the content of CaO than Portland cement, which is also supported by previous studies. But, Differently from previous studies, plastic working at the temperature of 650 was found an optimal condition under which cementitious powder from concrete waste could restore its hydraulic properties.

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Chemical Properties of Recycled Cement using Cementitious Powder from Waste Concrete (폐콘크리트 미분말을 이용한 재생시멘트의 화학적 특성)

  • Kang, Dong-Woo;Han, Chang-Woo;Ahn, Jae-Cheol;Park, Dong-Cheon;Kang, Byeung-Hee
    • 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.

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The Properties of Recycle Cement to Reuse Cementitious Powder from Neutralized Concrete Waste (중성화가 진행된 폐콘크리트계 미분말을 재활용한 재생시멘트의 물성)

  • Kang, Tae-Hun;Kim, Sung-Su;Jung, Min-Soo;Kang, Byung-He
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2003.11a
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    • pp.77-82
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    • 2003
  • The purpose of this study is development of technique to use cementitious powder as recycle cement produced from deteriorated Concrete waste which has a large quantity of calcium carbonate. Therefore, after having theoretical consideration based on the properties of high-heated concrete and concerning about neutralization of Concrete, we analysis chemical properties of ingredients of cementitious powder. After making origin cement paste, then processing the accelarated carbonation, we consider the properties of hydration and chemical properties of cementitious powder under various temperature conditions. As a result of the thermal analysis, the CaCo3 content of cementitious powder would affect decision of heat temperature to recover its hydrated ability because CaCo3 content is increased when neutralization is progressed. And as a result of XRD analysis, in case of origin powder of non-neutralized paste, CaO peak is found at 700℃. but, heat temperature to generate CaO would increase when the content of neutralized ingredients is increased. Finally, recycle cement heated at 700℃ shows the best compressive strength when the content of neutralized ingredients in recycle cement is less then 50%. However, it would be quite difficult to manage quality of recycle cement according to recycling points of various concrete waste.

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The Properties of Recycle Cement to Reuse Cementitious Powder from Neutralized Concrete Waste (중성화가 진행된 폐콘크리트계 미분말을 재활용한 재생시멘트의 물성)

  • 강태훈;김성수;정민수;강병희
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2003.05a
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    • pp.77-82
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    • 2003
  • The purpose of this study is development of technique to use cementitious powder as recycle cement produced from deteriorated Concrete waste which has a large quantity of calcium carbonate. Therefore, after having theoretical consideration based on the properties of hish-heated concrete and concerning about neutralization of Concrete, we analysis chemical properties of ingredients of cementitious powder After making origin cement paste, then processing the accelerated carbonation, we consider the properties of hydration and chemical properties of cementitious powder under various temperature conditions As a result of the thermal analysis, the CacO3 content of cementitious powder would affect decision of heat temperature to recover its hydrated ability because CacO3 content is increased when neutraliTation is preBlessed. And as a result of XRD analysis. in case of origin powder of non-neutralized paste, CaO peak is found at $700^{\circ}C$. but, heat temperature to generate CaO would increase when the content of neutralized ingredients is increased. Finally, recycle cement heated at $700^{\circ}C$ shows the best compressive strength when the content of neutralized ingredients in recycle cement is less then 50%. However, it would be quite difficult to manage quality of recycle cement according to recycling points of various concrete waste.

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A Study on Hydration Properties of Recycled Cement Mortar using Admixture Materials (혼화재료를 혼입한 재생시멘트 모르터의 수화특성에 관한 연구)

  • Park, Cha-Won;Kang, Byeung-Hee
    • Journal of the Korea Institute of Building Construction
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    • v.4 no.4
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    • pp.79-86
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    • 2004
  • The purpose of this study was the development of a recycling process to recover the hydraulic properties of hydration products which account for a large proportion of cementitious powder from concrete waste. This process was performed to recycle cementitious powder as recycle cement. Therefore, after the theoretical consideration of the properties of recycle process of recycled aggregates and cementitious powder, we investigated the hydraulic properties of cementitious powder under various temperature conditions in hardened mortar which was modeled on concrete waste. And we analyzed properties of chemical reactions of recycled cement with admixture materials such as Fly-Ash, Blast Furnace Slag As a result of the experiment, the most effective method to recover hydraulic properties of the cementitious powder from concrete waste was condition of burning at 700℃ for 120 minute. And it is shown that the fluidity of mortar was decreased rapidly when the burning temperature of recycle cement was increased. However, the compressive strength and fluidity were improved significantly when admixture materials such as Fly-Ash or Blast Furnace Slag was added.

Analysis on Calcination of Cementitious Powder of Waste Concrete for Raw Cement

  • Park, Dong-Cheon;Kwon, Eun-Hee;Ahn, Jae-Cheol
    • Journal of the Korea Institute of Building Construction
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    • v.14 no.1
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    • pp.54-60
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    • 2014
  • The purpose of this study is to examine whether cementitious powder separated from waste concrete can be used as an alternative raw material to limestone and reduce the usage of natural resource (limestone) and $CO_2$ emission based on recycling cementitious powder from waste concrete. Experiments actually analyzed the chemical composition of cementitious powder and performed hyperthermia analysis, measurement of free CaO and XRD analysis to measure the degree of recovery of hydration in the model of cementitious powder manufactured based on chemical composition. These were performed in each cementitious powder model at different calcination temperatures such as $900^{\circ}C$, $1200^{\circ}C$, $1300^{\circ}C$, $1400^{\circ}C$ and $1450^{\circ}C$. Through the experiments, it was found that the recovery of hydration was at a level which can be used as the alternative raw material for limestone, but the replacement ratio was directly affected by the degree of mixing of fine aggregate in less than $150{\mu}m$, which cannot be separated from cementitious powder. It was shown that there was no difference in the production of compounds involved in hydration at calcination temperatures of $1200^{\circ}C$ or higher. Therefore, to pursue the replacement of limestone and reduction of greenhouse gas by recycling cementitious powder, the development of technology to efficiently separate aggregate fine powder is required.

Hydration property of Recycled Cement Using Waste Cementitious Powder (폐콘크리트 미분말을 이용하여 제조한 시멘트의 수화특성)

  • Shin, Hyeon-Uk;Song, Hun;Chu, Yong-Sik;Lee, Jong-Kyu
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2014.11a
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    • pp.47-48
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    • 2014
  • This study is to hydration property of low carbon type recycled cement from waste cementitious powder and cement raw materials. Waste cementitious powder possible to low carbon type recycled cement in small part of additive materials. Also, low carbon type recycled cement using waste cementitious powder is suitable for low heat type cement.

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Carbonation Properties of Recycled Cement Mortar made of Cementitious Powder from Concrete Waste (폐콘크리트 미분말을 이용한 재생시멘트 모르터의 중성화 특성)

  • Kim Jin-Yang;Park Cha-Won;Ahn Jae-Cheol;Kang Byeung-Hee
    • 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.

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Carbonation Properties of Recycled Cement Mortar made of Cementitious Powder from Concrete Waste (폐콘크리트 미분말을 이용한 재생시멘트 모르터의 중성화 특성)

  • Park, Cha-Won;Ahn, Jae-Cheol;Kang, Byeung-Hee
    • 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.