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Rong Wu - One of the best experts on this subject based on the ideXlab platform.

  • study on the performance of fgd gypsum metakaolin cement composite Cementitious system
    Construction and Building Materials, 2016
    Co-Authors: Yongjuan Zhang, Rong Wu, Fei Pan
    Abstract:

    Abstract FGD gypsum is a desulfurization by-product from the steelworks, smelting plants, thermal power stations and so on and its output grows day by day, which means that the resource utilization of FGD gypsum is of economic and social significance. In this paper, FGD gypsum dried at 40 °C and FGD gypsum thermally activated at 800 °C were used as a water hardening supplementary Cementitious Component, and two series of FGD gypsum-metakaolin-cement composite Cementitious systems were prepared. After a series of studies, the following conclusions were obtained: The initial setting time of tested paste samples was longer and their interval between initial setting time and final setting time shortened while mortar fluidity decreased slightly. Early mortar strength of tested samples (to 28 d) was lower than the reference sample (namely Portland cement) and the strength increased obviously and some exceeded the reference sample after 28 days. Hydration products such as AFt and C-A-H existed at the same time from 1 day to 1 year in the samples with dried FGD gypsum and there was still unhydrated gypsum after a year. And crystallization of ettringite and gypsum could take place at the same time and partial crystal transformation from ettringite to AFm occurred from 40 d to 365 d with activated FGD gypsum. The volume stability of tested mortar samples kept in water was satisfied for one year in which ettringite amount was in 13–17% of harden paste and the ettringite content achieved 70–80% of the total ettringite amount at 7 d. Excessive crystallization of gypsum could also have an undesirable effect on the volume stability of harden mortar and mortar strength such as Sample B-5 from 40 d to 120 d. The volume stability of tested samples was good if the expansion stress was lower than the tensile strength.

  • study on the performance of fgd gypsum metakaolin cement composite Cementitious system
    Construction and Building Materials, 2016
    Co-Authors: Yongjuan Zhang, Rong Wu, Fei Pan
    Abstract:

    Abstract FGD gypsum is a desulfurization by-product from the steelworks, smelting plants, thermal power stations and so on and its output grows day by day, which means that the resource utilization of FGD gypsum is of economic and social significance. In this paper, FGD gypsum dried at 40 °C and FGD gypsum thermally activated at 800 °C were used as a water hardening supplementary Cementitious Component, and two series of FGD gypsum-metakaolin-cement composite Cementitious systems were prepared. After a series of studies, the following conclusions were obtained: The initial setting time of tested paste samples was longer and their interval between initial setting time and final setting time shortened while mortar fluidity decreased slightly. Early mortar strength of tested samples (to 28 d) was lower than the reference sample (namely Portland cement) and the strength increased obviously and some exceeded the reference sample after 28 days. Hydration products such as AFt and C-A-H existed at the same time from 1 day to 1 year in the samples with dried FGD gypsum and there was still unhydrated gypsum after a year. And crystallization of ettringite and gypsum could take place at the same time and partial crystal transformation from ettringite to AFm occurred from 40 d to 365 d with activated FGD gypsum. The volume stability of tested mortar samples kept in water was satisfied for one year in which ettringite amount was in 13–17% of harden paste and the ettringite content achieved 70–80% of the total ettringite amount at 7 d. Excessive crystallization of gypsum could also have an undesirable effect on the volume stability of harden mortar and mortar strength such as Sample B-5 from 40 d to 120 d. The volume stability of tested samples was good if the expansion stress was lower than the tensile strength.

Yongjuan Zhang - One of the best experts on this subject based on the ideXlab platform.

  • study on the performance of fgd gypsum metakaolin cement composite Cementitious system
    Construction and Building Materials, 2016
    Co-Authors: Yongjuan Zhang, Rong Wu, Fei Pan
    Abstract:

    Abstract FGD gypsum is a desulfurization by-product from the steelworks, smelting plants, thermal power stations and so on and its output grows day by day, which means that the resource utilization of FGD gypsum is of economic and social significance. In this paper, FGD gypsum dried at 40 °C and FGD gypsum thermally activated at 800 °C were used as a water hardening supplementary Cementitious Component, and two series of FGD gypsum-metakaolin-cement composite Cementitious systems were prepared. After a series of studies, the following conclusions were obtained: The initial setting time of tested paste samples was longer and their interval between initial setting time and final setting time shortened while mortar fluidity decreased slightly. Early mortar strength of tested samples (to 28 d) was lower than the reference sample (namely Portland cement) and the strength increased obviously and some exceeded the reference sample after 28 days. Hydration products such as AFt and C-A-H existed at the same time from 1 day to 1 year in the samples with dried FGD gypsum and there was still unhydrated gypsum after a year. And crystallization of ettringite and gypsum could take place at the same time and partial crystal transformation from ettringite to AFm occurred from 40 d to 365 d with activated FGD gypsum. The volume stability of tested mortar samples kept in water was satisfied for one year in which ettringite amount was in 13–17% of harden paste and the ettringite content achieved 70–80% of the total ettringite amount at 7 d. Excessive crystallization of gypsum could also have an undesirable effect on the volume stability of harden mortar and mortar strength such as Sample B-5 from 40 d to 120 d. The volume stability of tested samples was good if the expansion stress was lower than the tensile strength.

  • study on the performance of fgd gypsum metakaolin cement composite Cementitious system
    Construction and Building Materials, 2016
    Co-Authors: Yongjuan Zhang, Rong Wu, Fei Pan
    Abstract:

    Abstract FGD gypsum is a desulfurization by-product from the steelworks, smelting plants, thermal power stations and so on and its output grows day by day, which means that the resource utilization of FGD gypsum is of economic and social significance. In this paper, FGD gypsum dried at 40 °C and FGD gypsum thermally activated at 800 °C were used as a water hardening supplementary Cementitious Component, and two series of FGD gypsum-metakaolin-cement composite Cementitious systems were prepared. After a series of studies, the following conclusions were obtained: The initial setting time of tested paste samples was longer and their interval between initial setting time and final setting time shortened while mortar fluidity decreased slightly. Early mortar strength of tested samples (to 28 d) was lower than the reference sample (namely Portland cement) and the strength increased obviously and some exceeded the reference sample after 28 days. Hydration products such as AFt and C-A-H existed at the same time from 1 day to 1 year in the samples with dried FGD gypsum and there was still unhydrated gypsum after a year. And crystallization of ettringite and gypsum could take place at the same time and partial crystal transformation from ettringite to AFm occurred from 40 d to 365 d with activated FGD gypsum. The volume stability of tested mortar samples kept in water was satisfied for one year in which ettringite amount was in 13–17% of harden paste and the ettringite content achieved 70–80% of the total ettringite amount at 7 d. Excessive crystallization of gypsum could also have an undesirable effect on the volume stability of harden mortar and mortar strength such as Sample B-5 from 40 d to 120 d. The volume stability of tested samples was good if the expansion stress was lower than the tensile strength.

Fei Pan - One of the best experts on this subject based on the ideXlab platform.

  • study on the performance of fgd gypsum metakaolin cement composite Cementitious system
    Construction and Building Materials, 2016
    Co-Authors: Yongjuan Zhang, Rong Wu, Fei Pan
    Abstract:

    Abstract FGD gypsum is a desulfurization by-product from the steelworks, smelting plants, thermal power stations and so on and its output grows day by day, which means that the resource utilization of FGD gypsum is of economic and social significance. In this paper, FGD gypsum dried at 40 °C and FGD gypsum thermally activated at 800 °C were used as a water hardening supplementary Cementitious Component, and two series of FGD gypsum-metakaolin-cement composite Cementitious systems were prepared. After a series of studies, the following conclusions were obtained: The initial setting time of tested paste samples was longer and their interval between initial setting time and final setting time shortened while mortar fluidity decreased slightly. Early mortar strength of tested samples (to 28 d) was lower than the reference sample (namely Portland cement) and the strength increased obviously and some exceeded the reference sample after 28 days. Hydration products such as AFt and C-A-H existed at the same time from 1 day to 1 year in the samples with dried FGD gypsum and there was still unhydrated gypsum after a year. And crystallization of ettringite and gypsum could take place at the same time and partial crystal transformation from ettringite to AFm occurred from 40 d to 365 d with activated FGD gypsum. The volume stability of tested mortar samples kept in water was satisfied for one year in which ettringite amount was in 13–17% of harden paste and the ettringite content achieved 70–80% of the total ettringite amount at 7 d. Excessive crystallization of gypsum could also have an undesirable effect on the volume stability of harden mortar and mortar strength such as Sample B-5 from 40 d to 120 d. The volume stability of tested samples was good if the expansion stress was lower than the tensile strength.

  • study on the performance of fgd gypsum metakaolin cement composite Cementitious system
    Construction and Building Materials, 2016
    Co-Authors: Yongjuan Zhang, Rong Wu, Fei Pan
    Abstract:

    Abstract FGD gypsum is a desulfurization by-product from the steelworks, smelting plants, thermal power stations and so on and its output grows day by day, which means that the resource utilization of FGD gypsum is of economic and social significance. In this paper, FGD gypsum dried at 40 °C and FGD gypsum thermally activated at 800 °C were used as a water hardening supplementary Cementitious Component, and two series of FGD gypsum-metakaolin-cement composite Cementitious systems were prepared. After a series of studies, the following conclusions were obtained: The initial setting time of tested paste samples was longer and their interval between initial setting time and final setting time shortened while mortar fluidity decreased slightly. Early mortar strength of tested samples (to 28 d) was lower than the reference sample (namely Portland cement) and the strength increased obviously and some exceeded the reference sample after 28 days. Hydration products such as AFt and C-A-H existed at the same time from 1 day to 1 year in the samples with dried FGD gypsum and there was still unhydrated gypsum after a year. And crystallization of ettringite and gypsum could take place at the same time and partial crystal transformation from ettringite to AFm occurred from 40 d to 365 d with activated FGD gypsum. The volume stability of tested mortar samples kept in water was satisfied for one year in which ettringite amount was in 13–17% of harden paste and the ettringite content achieved 70–80% of the total ettringite amount at 7 d. Excessive crystallization of gypsum could also have an undesirable effect on the volume stability of harden mortar and mortar strength such as Sample B-5 from 40 d to 120 d. The volume stability of tested samples was good if the expansion stress was lower than the tensile strength.

J N Kitchener - One of the best experts on this subject based on the ideXlab platform.

  • massive use of pulverised fuel ash in concrete for the construction of a u k power station
    Waste Management, 1996
    Co-Authors: D R Davies, J N Kitchener
    Abstract:

    This paper describes the incorporation and benefits of pulverised fuel ash (PFA) in nearly 620,000 m2 of concrete used in the construction of the U.K.'s first commercial pressurised light water nuclear reactor power station, Sizewell B, Suffolk. Overall nearly 100,000 t of PFA, 1300 t of sintered fly ash lightweight aggregate, and nearly 137,000 t of Ordinary Portland Cement (OPC) were used in the works. Generally in the construction of the main power station buildings, structural concrete with a characteristic strength of 45 N/mm2 was placed and included fly ash as 40% of the Cementitious Component. Also, concrete with fly ash as 50% of the Cementitious Component was placed as mass fill. The programme of research is reported, including sulphate resistance, heat of hydration, elastic properties, alkali-silica reaction, and long-term strength test results. Test and field results are presented and discussed. Strict quality assurance procedures were enforced and statistical summaries are offered to give an insight into the quality of control exercised. Test work and long-term results are also outlined.

D R Davies - One of the best experts on this subject based on the ideXlab platform.

  • massive use of pulverised fuel ash in concrete for the construction of a u k power station
    Waste Management, 1996
    Co-Authors: D R Davies, J N Kitchener
    Abstract:

    This paper describes the incorporation and benefits of pulverised fuel ash (PFA) in nearly 620,000 m2 of concrete used in the construction of the U.K.'s first commercial pressurised light water nuclear reactor power station, Sizewell B, Suffolk. Overall nearly 100,000 t of PFA, 1300 t of sintered fly ash lightweight aggregate, and nearly 137,000 t of Ordinary Portland Cement (OPC) were used in the works. Generally in the construction of the main power station buildings, structural concrete with a characteristic strength of 45 N/mm2 was placed and included fly ash as 40% of the Cementitious Component. Also, concrete with fly ash as 50% of the Cementitious Component was placed as mass fill. The programme of research is reported, including sulphate resistance, heat of hydration, elastic properties, alkali-silica reaction, and long-term strength test results. Test and field results are presented and discussed. Strict quality assurance procedures were enforced and statistical summaries are offered to give an insight into the quality of control exercised. Test work and long-term results are also outlined.