Journal of Research of the Taiheiyo Cement Corporation
Online ISSN : 2759-6826
Print ISSN : 1344-8773
ISSN-L : 1344-8773
Volume 2020, Issue 179
Displaying 1-8 of 8 articles from this issue
  • Hiroshi HIRAO, Kotaro HAYASHI, Koji NOMURA, Hikotsugu HYODO
    2021 Volume 2020 Issue 179 Pages 3-14
    Published: February 26, 2021
    Released on J-STAGE: January 23, 2025
    RESEARCH REPORT / TECHNICAL REPORT FREE ACCESS
     Taiheiyo Cement Corporation has formulated a long-term vision of greenhouse gas emissions reduction toward 2050, in line with current growing public-concern in climate change as well as future perspectives for the global cement industries. This paper presents our vision and action on CO2 emissions reduction. In addition, the position of our long-term vision is described based on an overview of current global trends in the cement industry related to CO2 emissions reduction.
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  • Hikotsugu HYODO, Seiichi HOSHINO, Hiroshi HIRAO, Koji NOMURA
    2021 Volume 2020 Issue 179 Pages 15-30
    Published: February 26, 2021
    Released on J-STAGE: January 23, 2025
    RESEARCH REPORT / TECHNICAL REPORT FREE ACCESS
     Cement-based materials spontaneously uptake carbon dioxide (CO2) due to carbonation. Once the CO2 is sequestered in the cement-based materials, it will not be released to the atmosphere again. Recently, this property is highlighted as a new technological approach, in the face of growing societal demand on CO2 emissions reduction. This paper summarized recent studies on CO2 uptake and sequestration by carbonation of cement-based materials. It includes an area of studies on mechanism of carbonation, an estimation method for CO2 uptake from atmosphere during concrete life-cycle and an accelerated carbonation curing technologies for cement based materials.
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  • Yuya SANO, Kensuke KITAZAWA, Junichi TERASAKI, Kouichi NAITOU
    2021 Volume 2020 Issue 179 Pages 31-40
    Published: February 26, 2021
    Released on J-STAGE: January 23, 2025
    RESEARCH REPORT / TECHNICAL REPORT FREE ACCESS
     This study evaluated the effects of operating conditions of the Taiheiyo Multi-Purpose (TMP) kiln burner on the drop rate and combustion behavior of waste plastics in the kiln by using the Computational Fluid Dynamics (CFD) in order to find the optimum conditions to achieve both of stable kiln operation and increased feed of waste plastics to the kiln burner. The results showed that increasing the air speed or volume at each air port of the TMP kiln burner accelerated the combustion of the waste plastics and decreased the amount of waste plastics dropping onto the clinker surface in the kiln. It was also found that increasing the speed or volume of the axial air had little effect on the heat generation and gas temperature profiles in the kiln, resulting in a combustion behavior equivalent to conventional performance. Although increasing the air volume had similar effects to increasing the air speed, the resultant increase in the air inflow into the kiln could affect the fuel consumption. These results suggested that the optimum conditions would be obtained by increasing the speed of the axial air.
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  • Ayuka NAKAGUCHI, Yoko HIRANO, Daisuke KUROKAWA, Shunichiro UCHIDA
    2021 Volume 2020 Issue 179 Pages 41-52
    Published: February 26, 2021
    Released on J-STAGE: January 23, 2025
    RESEARCH REPORT / TECHNICAL REPORT FREE ACCESS
     Although increasing the amount of minor additional constituents in ordinary Portland cement (OPC) is one of the effective approaches for reducing the CO2 emissions from cement industry, it naturally reduces the amount of use of alternative waste raw materials due to the decreased clinker ratio in cement. Cement clinker with a higher aluminate phase may possibly achieve CO2 emissions reduction without reducing the waste use, but its effect on the cement and concrete quality has not been made clear enough.
     In this study, a variety of blended cements containing different types of minor additive constituents in different amounts were prepared by using six base cements varied in clinker compositions and fineness and three minor additional constituents, and the physical properties and environmental impact of the blended cements were thoroughly investigated. The results showed that it was possible to reduce CO2 emissions and increase the amount of waste use while maintaining adequate quality of cement by increasing the amount of aluminate in the base cement by 1 to 2% compared to the conventional OPC and increasing the minor additional constituents to 10%.
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  • Katsuya KONO, Eiki YASUDA, Daisuke KOGAME, Atsushi NAKAMURA, Ai SHIROD ...
    2021 Volume 2020 Issue 179 Pages 53-60
    Published: February 26, 2021
    Released on J-STAGE: January 23, 2025
    RESEARCH REPORT / TECHNICAL REPORT FREE ACCESS
     Recently there are an increasing number of studies about concrete with a high content of ground granulated blast-furnace slag (BS) as a part of efforts for reduction of carbon-dioxide emissions. However, little has been studied about the shear capacity of reinforced concrete (RC) beams with a high BS content. In this study, shear loading tests of RC beams with a high BS content were performed to investigate the shear load resisting mechanism. Some of the important findings were as follows: (1) normal strength concrete with blast-furnace slag cement (BSC) exhibited a larger shrinkage compared to concrete with ordinary Portland cement (OPC) or fly ash cement (FAC) of equivalent compressive strength until the age of 28 days; and (2) shear capacity of the normal strength RC beam with BSC was lower by about 10% compared to that of RC beams with OPC or FAC of equivalent compressive strength at the age of 28 days.
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  • Yuki CHIBA, Toru OTA, Kazushi IZUMI
    2021 Volume 2020 Issue 179 Pages 61-71
    Published: February 26, 2021
    Released on J-STAGE: January 23, 2025
    RESEARCH REPORT / TECHNICAL REPORT FREE ACCESS
     A chemical absorption technology was adopted for its simplicity and ease of operation and placed in the Fujiwara plant for the small-scale trials. Demonstration trials have been carried out to evaluate the performance of CO2 separation and capture from cement kiln exhaust gas since January 2019.
     Through the trials, stable CO2 capture performance and recovery of high-purity CO2 gas were verified, which demonstrated the applicability of the chemical absorption technology to the cement kiln exhaust gas generated in our existing cement plants.
     As it was also found that some components in the kiln exhaust gas degraded the CO2 capture performance, effects of minor components in the kiln exhaust gas on the CO2 absorption performance and the optimal operation conditions for effective CO2 recovery should be studied at future scaled-up trials.
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