• Cement Symposium
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• no.1
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• pp.64-68
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• 1973

One of the most difficult problems in cement rotary kiln operation must be ring and coating formation. In the Dopol kiln with the capacity of 1,500 t/d($4.4m\phi\times70mL$, meal rings have been accreted on transit zone and end of the kiln and

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.11a
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• pp.209-210
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• 2012

Cement is an essential material for social infrastructure. Cement production process for cement itself is energy-intensive and requires a large amount of natural resources for fuel and raw materials. This study is to development of recycled cement from waste concrete powder in manufacturing process of recycled aggregate concrete. Recycled cement is low carbon and green growth materials concept for eco friendly construction environment. From the test results, waste concrete powder is same chemical proportion regardless of manufacturing process of recycled aggregate concrete.

• KCI Concrete Journal
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• v.12 no.1
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• pp.79-89
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• 2000

This research developed an accelerated curing processe for cellulose fiber reinforced cement composites using vigorous reaction between carbon dioxide and cement paste. A wet-processed cellulose fiber reinforced cement system was considered. Carbonation curing was used to complement conventional accelerated curing. The parametric study followed by optimization investigation indicated that the carbonation curing can enhance the productivity and energy efficiency of manufacturing cellulose fiber reinforced cement composites. This also adds environmental benefits to the technical and economical advantages of the technology.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.144-145
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• 2020

Recently, the cement industry has been using various wastes as raw materials and fuel for cement as an eco-friendly business. However, most of these waste resources contain large amounts of chloride and alkali, which are concentrated in manufacturing facilities and adversely affect cement production products. Accordingly, in the cement production process, the chlorine ion contained in cement is managed by introducing the Chlorine Bypass System (CBS) into the manufacturing facility and releasing the dust. However, the processing volume of CBS-Dust has been limited due to the shortage of domestic processing companies, and the cost has also been raised, requiring measures to be taken in dealing with CBS-Dust. In this study, rheological properties of CBS-Dust incorporated paste are tested. With the increase of CBS-Dust, flow was decreased due to enhanced viscosity.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.3
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• pp.330-337
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• 2021

3D printing is not only at the fundamental study and small-scale level, but has recently been producing buildings that can be inhabited by people. Buildings require a lot of cost and labor to work on the form work, but if 3D printing is applied to the building, the construction industry is received attention from technologies using 3D printing as it can reduce the construction period and cost. 3D printing technology for buildings can be divided into structural and non-structural materials, of which 3D printing is applied to non-structural materials. Because 3D printing needs to be additive manufacturing, control such as curing speed and workability is needed. Since cement mortar has a large shrinkage due to evaporation of water, cement polymer dispersion is used to improve the hardening speed, workability, and adhesion strength. The addition of polymer dispersion to cement mortar improves the tensile strength and brittleness between the cement hydrate and the polymer film. Cement mortar using polymer materials can be additive manufacturing but it has limited height that can be additive manufacturing due to its high density. When light-weight materials are mixed with polymer cement mortar, the density of polymer cement mortar is lowered and the height of additive manufacturing, so it is essential to use light-weight materials. However, the use of EVA redispersible polymer powder and light-weight materials, additional damage such as cracks in cement mortar can occur at high temperatures such as fires. This study produced a test specimen incorporating light-weight materials and EVA redispersible polymer powder to produce exterior building materials using 3D printing, and examined flame resistance performance through water absorption rate, length change rate, and cone calorimeter test and non-flammable test. From the test result, the test specimen using silica sand and light-weight aggregate showed good flame resistance performance, and if the EVA redispersible polymer powder is applied below 5%, it shows good flame resistance performance.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.3
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• pp.78-83
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• 2010

This paper presents the feasibility of incorporating ultrafine particles collected in the separator bag filter (separator bag filter cement, SBFC) during the cement manufacturing process as an substitution material for cement. SBFC does not require additional processes needed in the existing processes to manufacture high early strength cement such as modifying mineral components and adjusting the firing temperature. Moreover, it can also solve the issue of efficiency decrease resulted from the increase of the grinding time applied in the existing process of manufacturing microcement. Therefore, this research has examined the characteristics of SBFC and fresh properties and mechanical properties after making paste and mortar using SBFC in order to use SBFC as a material to gain early strength of concrete. For results, analyzing the chemical composition and physical properties of SBFC, its blaine value was $6,953cm^3/g$, about double than that of OPC, but its chemical composition showed no significant difference. According to the result of the paste and mortar examination, the paste and mortar mixed with SBFC showed a lower flowability, earlier setting time, and higher compressive strength than that with OPC. The result of microstructure analysis of paste, the paste mixed with SBFC indicated about 9% lower internal porosity at an early age than that of OPC. The compressive strength and flexural strength of mortar were higher in the order of SBFC ratio of 100, 50 and 0% SBFC.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.757-760
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• 2006

This study aims to manufacture ultra fine cement(UFC) with a multi air-classifier of the dry-type. The classifier employed and devised for materials refining was a cyclone type fitted with an air suction device. This study also investigates the basic physical properties and quality of UFC and evaluates its utilizable possibility as a construction material. The basic properties of the UFC containing granulated blast furnace slag were analyzed and examined through recovery ratio, particle size distribution, scanning electron microscopy and compressive strength. Results obtained from the analysis of ultra fine cement have shown that there are possibilities for manufacturing UFC, which could compensate the weak properties of ordinary Portland cement.

• Resources Recycling
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• v.30 no.6
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• pp.68-75
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• 2021

This study aims to investigate the manufacturing process of calcium chloride-based special cement, i.e., CCA (calcium chloro aluminate, C₁₁A₇·CaCl₂), which uses limestone, by using one type of random industrial by-product, domestic coal ash, cement kiln dust. The manufacturing process of was examined in detail, and the results suggested that the amount of CCA synthesized increased with an increase in the firing temperature. The manufacturing process of CCA was investigated at 1200℃, which was determined as the optimum firing temperature. The results showed that in general, the amount of CCA synthesized tended to increase with an increase in the firing time; however, the clinker melted when the firing time was more than 30 min, thereby suggesting that a firing time of less than 20 min would be suitable for the clinkering process. The optimal firing conditions for manufacturing CCA were obtained as follows: heating rate of 10 ℃/min, firing temperature of 1200 ℃, and holding time of 20 min. The results also suggest that manufacturing CCA will be easier when high chlorine-containing cement kiln dust is used.

• Journal of the Korea Institute of Building Construction
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• v.6 no.3 s.21
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• pp.75-82
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• 2006

This study investigates the influence of various blending factors on cement paste fluidity and find out the most effective evaluation method of cement paste flow, comparing flow test apparatuses such as ring flow(R-F), flow cone(F-C) and mini slump(M-S). A viscometer also measures the rheology coefficients to secure faithful numerical data. Firstly, series I examines cement paste, affected by several cement products and mineral admixture types in the range of W/B 40%, ordinary fluidity, and W/B 30%, high fluidity. In this series, the three types of cement product depended on companies, are randomly used and the mineral admixture, such as fly ash, blast furnace slag and silica fume, are incorporated in the cement paste, in response to the ratio of 10, 20, to 30%, respectively. In addition, series II studies various chemical admixture types, affecting the cement paste. This series is carried out with manufacturing companies and component types in the range of W/C 30%, high fluidity. For the manufacturing companies, randomly four products are used and for the component types, polycaboxylate, melamine, naphthalene and lignosulfonate type are chosen. Test results showed that in the fluidity test of cement paste considering various types of blending factors, R-F exhibited similar tendency with F-C and M-S. In the analysis of consistency curves measured by viscometer, the fluidity evaluation method using flow test apparatuses was significantly effective, except for the some of the low fluidity specimens. In conclusion of this study, R-F was the most convenient, faithful and effective fluidity evaluation method of cement paste.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.10a
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• pp.144-149
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• 1993

The results of an experimental study on the manufacture and the mechanical properties of carbon fiber reinforced silica fume.cement composites and light weight fly ash.cement composites are presented in this paper. The CF reinforced silica fume.cement composites using silica fume early strength cement were prepared with Pan-derived or Pitch-derived CF, and Lt. Wt, fly ash.cement composites using fly ash, early strength cement, perlite and a small amount of foaming agent. As the test results show, the flexural strength, toughness and ductility of CF reinforced silica fume .cement composites were remarkably increased by fiber contents. Also, the manufacturing process technology of Lt. Wt. fly ash.cement composites was developed and its optimum mix proportions were proposed. And the compressive and flexural strength of the fly ash.cement composites by hot water cured were improved even more than by moist cured, but are decreased by increasing fly ash replaced ratio for cement.