The Experts below are selected from a list of 537 Experts worldwide ranked by ideXlab platform

Wenhui Duan - One of the best experts on this subject based on the ideXlab platform.

  • effects of graphene oxide aggregates on hydration degree sorptivity and tensile splitting strength of Cement Paste
    Composites Part A-applied Science and Manufacturing, 2017
    Co-Authors: Samuel Chuah, Yan Ming Liu, Wenhui Duan
    Abstract:

    Abstract It has recently been found the graphene oxide (GO) aggregates form in Cement Paste due to the chemical cross-linking of calcium cations. Therefore, the effects of GO addition on the properties of Cement based materials should be dependent on the properties of GO aggregates rather than GO nanosheets. In this study, GO aggregates were first characterized by particle size measurement. Then, the effects of GO aggregates on the degree of hydration, sorptivity, and tensile strength of Cement Paste were investigated. The aspect ratio of GO aggregates is much larger than that of the original GO nanosheets. Compared to Plain Cement Paste, the increase of non-evaporable water content of the Cement Paste was found to be very limited, around 1.17% and 3.90% for Cement Pastes containing 0.02% and 0.04% by weight GO, respectively. The sorptivity of Cement Paste, especially the secondary sorptivity, was notably reduced for GO incorporated Cement Paste. The tensile strength was significantly improved by GO aggregates. Incorporation of 0.04% by weight GO increased the tensile strength by 67% compared to that of Plain Cement Paste.

  • effects of nanoalumina and graphene oxide on early age hydration and mechanical properties of Cement Paste
    Journal of Materials in Civil Engineering, 2017
    Co-Authors: Shu Jian Chen, Yan Ming Liu, Guangcheng Long, Wenhui Duan
    Abstract:

    The effects of nanoalumina (NA) and graphene oxide (GO) on the early-age hydration and mechanical properties of portland Cement Pastes were investigated in this study. The hydration heat release rate and cumulative heat of Cement Pastes incorporating different dosages of NA and GO were evaluated using an isothermal calorimeter measurement method. Early-age electrical resistivity development was investigated by a noncontact electrical resistivity technique. The results show that both NA and GO could efficiently accelerate Cement hydration. As a physical filler, NA significantly accelerates the hydration of tricalcium aluminate (CA) in Cement. On the other hand, GO is able to obviously reduce the dormant period of Cement hydration and shift the heat flow peaks to the left by accelerating the hydration of tricalcium silicate (CS) in Cement. Compared to Plain Cement Pastes, both the compressive and flexural strengths of Cement Pastes incorporating NA or GO are significantly increased. However, when NA and GO contents exceed the optimal amounts, improvements in flexural strength tend to decline, which is probably due to particle agglomeration. NA-Cement Paste exhibited slightly higher electrical resistivity than Plain Cement Paste during hydration acceleration and deceleration stages. But GO-Cement Paste clearly showed lower electrical resistivity, which might be attributed to iron diffusion caused by GO with large surface areas.

  • effects of graphene oxide on early age hydration and electrical resistivity of portland Cement Paste
    Construction and Building Materials, 2017
    Co-Authors: Shu Jian Chen, Wenhui Duan, Yan Ming Liu, Surendra P Shah
    Abstract:

    The effects of graphene oxide (GO) on the early-age hydration process and mechanical properties of Portland Cement Paste were experimentally investigated in this study. Based on an isothermal calorimeter measurement, the hydration rate of Cement was observed to increase with the increase of GO content by nucleation effect. On the other hand, the electrical resistivity development of GO-Cement Paste was monitored using a non-contact electrical resistivity device. The result showed that electrical the resistivity of GO-Cement Paste was evidently higher than that of Plain Cement Paste. However, Cement Paste with excessive amounts of GO exhibited a decreased electrical resistivity due to the massive ion diffusion caused by GO. Compared to Plain Cement Paste, the GO-Cement Paste exhibited obviously higher compressive and flexural strengths, but the enhanCements in compressive strength began to decline when the GO amount was greater than 0.04%. The microstructure characterization indicated that GO can apparently densify the Cement Pastes with less porosity and hydrates networking, which is consistent with the results of hydration acceleration and strength enhanCement.

  • effects of graphene oxide aggregates on hydration degree sorptivity and tensile splitting strength of Cement Paste part a applied science and manufacturing
    Composites, 2017
    Co-Authors: Samuel Chuah, Yan Ming Liu, Wenhui Duan
    Abstract:

    It has recently been found the graphene oxide (GO) aggregates form in Cement Paste due to the chemical cross-linking of calcium cations. Therefore, the effects of GO addition on the properties of Cement based materials should be dependent on the properties of GO aggregates rather than GO nanosheets. In this study, GO aggregates were first characterized by particle size measurement. Then, the effects of GO aggregates on the degree of hydration, sorptivity, and tensile strength of Cement Paste were investigated. The aspect ratio of GO aggregates is much larger than that of the original GO nanosheets. Compared to Plain Cement Paste, the increase of non-evaporable water content of the Cement Paste was found to be very limited, around 1.17% and 3.90% for Cement Pastes containing 0.02% and 0.04% by weight GO, respectively. The sorptivity of Cement Paste, especially the secondary sorptivity, was notably reduced for GO incorporated Cement Paste. The tensile strength was significantly improved by GO aggregates. Incorporation of 0.04% by weight GO increased the tensile strength by 67% compared to that of Plain Cement Paste.

Surendra P Shah - One of the best experts on this subject based on the ideXlab platform.

  • effects of graphene oxide on early age hydration and electrical resistivity of portland Cement Paste
    Construction and Building Materials, 2017
    Co-Authors: Shu Jian Chen, Wenhui Duan, Yan Ming Liu, Surendra P Shah
    Abstract:

    The effects of graphene oxide (GO) on the early-age hydration process and mechanical properties of Portland Cement Paste were experimentally investigated in this study. Based on an isothermal calorimeter measurement, the hydration rate of Cement was observed to increase with the increase of GO content by nucleation effect. On the other hand, the electrical resistivity development of GO-Cement Paste was monitored using a non-contact electrical resistivity device. The result showed that electrical the resistivity of GO-Cement Paste was evidently higher than that of Plain Cement Paste. However, Cement Paste with excessive amounts of GO exhibited a decreased electrical resistivity due to the massive ion diffusion caused by GO. Compared to Plain Cement Paste, the GO-Cement Paste exhibited obviously higher compressive and flexural strengths, but the enhanCements in compressive strength began to decline when the GO amount was greater than 0.04%. The microstructure characterization indicated that GO can apparently densify the Cement Pastes with less porosity and hydrates networking, which is consistent with the results of hydration acceleration and strength enhanCement.

  • image analysis techniques for characterization of pore structure of Cement based materials
    Cement and Concrete Research, 1994
    Co-Authors: D Lange, Hamlin M Jennings, Surendra P Shah
    Abstract:

    Abstract This paper explores several image analysis techniques that provide insight into the nature of pore structure as observed in backscattered electron images of polished sections. Image analysis techniques used in this study include sizing, two-point correlation, and fractal analyses. The spatial parameters computed by these techniques have potential for relating microstructure to material properties. Specimens include Plain Cement Paste, Pastes with silica fume, and mortars. Tests include determination of total porosity, mercury intrusion porosimetry (MIP), compression and flexural testing. The two-parameter fracture model is used to characterize fracture properties. Pore size distribution from MIP is compared to pore size distribution derived from BSE images.

Yan Ming Liu - One of the best experts on this subject based on the ideXlab platform.

  • effects of graphene oxide aggregates on hydration degree sorptivity and tensile splitting strength of Cement Paste
    Composites Part A-applied Science and Manufacturing, 2017
    Co-Authors: Samuel Chuah, Yan Ming Liu, Wenhui Duan
    Abstract:

    Abstract It has recently been found the graphene oxide (GO) aggregates form in Cement Paste due to the chemical cross-linking of calcium cations. Therefore, the effects of GO addition on the properties of Cement based materials should be dependent on the properties of GO aggregates rather than GO nanosheets. In this study, GO aggregates were first characterized by particle size measurement. Then, the effects of GO aggregates on the degree of hydration, sorptivity, and tensile strength of Cement Paste were investigated. The aspect ratio of GO aggregates is much larger than that of the original GO nanosheets. Compared to Plain Cement Paste, the increase of non-evaporable water content of the Cement Paste was found to be very limited, around 1.17% and 3.90% for Cement Pastes containing 0.02% and 0.04% by weight GO, respectively. The sorptivity of Cement Paste, especially the secondary sorptivity, was notably reduced for GO incorporated Cement Paste. The tensile strength was significantly improved by GO aggregates. Incorporation of 0.04% by weight GO increased the tensile strength by 67% compared to that of Plain Cement Paste.

  • effects of nanoalumina and graphene oxide on early age hydration and mechanical properties of Cement Paste
    Journal of Materials in Civil Engineering, 2017
    Co-Authors: Shu Jian Chen, Yan Ming Liu, Guangcheng Long, Wenhui Duan
    Abstract:

    The effects of nanoalumina (NA) and graphene oxide (GO) on the early-age hydration and mechanical properties of portland Cement Pastes were investigated in this study. The hydration heat release rate and cumulative heat of Cement Pastes incorporating different dosages of NA and GO were evaluated using an isothermal calorimeter measurement method. Early-age electrical resistivity development was investigated by a noncontact electrical resistivity technique. The results show that both NA and GO could efficiently accelerate Cement hydration. As a physical filler, NA significantly accelerates the hydration of tricalcium aluminate (CA) in Cement. On the other hand, GO is able to obviously reduce the dormant period of Cement hydration and shift the heat flow peaks to the left by accelerating the hydration of tricalcium silicate (CS) in Cement. Compared to Plain Cement Pastes, both the compressive and flexural strengths of Cement Pastes incorporating NA or GO are significantly increased. However, when NA and GO contents exceed the optimal amounts, improvements in flexural strength tend to decline, which is probably due to particle agglomeration. NA-Cement Paste exhibited slightly higher electrical resistivity than Plain Cement Paste during hydration acceleration and deceleration stages. But GO-Cement Paste clearly showed lower electrical resistivity, which might be attributed to iron diffusion caused by GO with large surface areas.

  • effects of graphene oxide on early age hydration and electrical resistivity of portland Cement Paste
    Construction and Building Materials, 2017
    Co-Authors: Shu Jian Chen, Wenhui Duan, Yan Ming Liu, Surendra P Shah
    Abstract:

    The effects of graphene oxide (GO) on the early-age hydration process and mechanical properties of Portland Cement Paste were experimentally investigated in this study. Based on an isothermal calorimeter measurement, the hydration rate of Cement was observed to increase with the increase of GO content by nucleation effect. On the other hand, the electrical resistivity development of GO-Cement Paste was monitored using a non-contact electrical resistivity device. The result showed that electrical the resistivity of GO-Cement Paste was evidently higher than that of Plain Cement Paste. However, Cement Paste with excessive amounts of GO exhibited a decreased electrical resistivity due to the massive ion diffusion caused by GO. Compared to Plain Cement Paste, the GO-Cement Paste exhibited obviously higher compressive and flexural strengths, but the enhanCements in compressive strength began to decline when the GO amount was greater than 0.04%. The microstructure characterization indicated that GO can apparently densify the Cement Pastes with less porosity and hydrates networking, which is consistent with the results of hydration acceleration and strength enhanCement.

  • effects of graphene oxide aggregates on hydration degree sorptivity and tensile splitting strength of Cement Paste part a applied science and manufacturing
    Composites, 2017
    Co-Authors: Samuel Chuah, Yan Ming Liu, Wenhui Duan
    Abstract:

    It has recently been found the graphene oxide (GO) aggregates form in Cement Paste due to the chemical cross-linking of calcium cations. Therefore, the effects of GO addition on the properties of Cement based materials should be dependent on the properties of GO aggregates rather than GO nanosheets. In this study, GO aggregates were first characterized by particle size measurement. Then, the effects of GO aggregates on the degree of hydration, sorptivity, and tensile strength of Cement Paste were investigated. The aspect ratio of GO aggregates is much larger than that of the original GO nanosheets. Compared to Plain Cement Paste, the increase of non-evaporable water content of the Cement Paste was found to be very limited, around 1.17% and 3.90% for Cement Pastes containing 0.02% and 0.04% by weight GO, respectively. The sorptivity of Cement Paste, especially the secondary sorptivity, was notably reduced for GO incorporated Cement Paste. The tensile strength was significantly improved by GO aggregates. Incorporation of 0.04% by weight GO increased the tensile strength by 67% compared to that of Plain Cement Paste.

Xiangming Zhou - One of the best experts on this subject based on the ideXlab platform.

  • study on utilization of carboxyl group decorated carbon nanotubes and carbonation reaction for improving strengths and microstructures of Cement Paste
    Nanomaterials, 2016
    Co-Authors: Waiching Tang, Xiangming Zhou
    Abstract:

    Carbon nanotubes (CNTs) have excellent mechanical properties and can be used to reinforce Cement-based materials. On the other hand, the reaction product of carbonation with hydroxides in hydrated Cement Paste can reduce the porosity of Cement-based materials. In this study, a novel method to improve the strength of Cement Paste was developed through a synergy of carbon nanotubes decorated with carboxyl group and carbonation reactions. The experimental results showed that the carboxyl group (–COOH) of decorated carbon nanotubes and the surfactant can control the morphology of the calcium carbonate crystal of carbonation products in hydrated Cement Paste. The spindle-like calcium carbonate crystals showed great morphological differences from those observed in the conventional carbonation of Cement Paste. The spindle-like calcium carbonate crystals can serve as fiber-like reinforCements to reinforce the Cement Paste. By the synergy of the carbon nanotubes and carbonation reactions, the compressive and flexural strengths of Cement Paste were significantly improved and increased by 14% and 55%, respectively, when compared to those of Plain Cement Paste.

Samuel Chuah - One of the best experts on this subject based on the ideXlab platform.

  • effects of graphene oxide aggregates on hydration degree sorptivity and tensile splitting strength of Cement Paste
    Composites Part A-applied Science and Manufacturing, 2017
    Co-Authors: Samuel Chuah, Yan Ming Liu, Wenhui Duan
    Abstract:

    Abstract It has recently been found the graphene oxide (GO) aggregates form in Cement Paste due to the chemical cross-linking of calcium cations. Therefore, the effects of GO addition on the properties of Cement based materials should be dependent on the properties of GO aggregates rather than GO nanosheets. In this study, GO aggregates were first characterized by particle size measurement. Then, the effects of GO aggregates on the degree of hydration, sorptivity, and tensile strength of Cement Paste were investigated. The aspect ratio of GO aggregates is much larger than that of the original GO nanosheets. Compared to Plain Cement Paste, the increase of non-evaporable water content of the Cement Paste was found to be very limited, around 1.17% and 3.90% for Cement Pastes containing 0.02% and 0.04% by weight GO, respectively. The sorptivity of Cement Paste, especially the secondary sorptivity, was notably reduced for GO incorporated Cement Paste. The tensile strength was significantly improved by GO aggregates. Incorporation of 0.04% by weight GO increased the tensile strength by 67% compared to that of Plain Cement Paste.

  • effects of graphene oxide aggregates on hydration degree sorptivity and tensile splitting strength of Cement Paste part a applied science and manufacturing
    Composites, 2017
    Co-Authors: Samuel Chuah, Yan Ming Liu, Wenhui Duan
    Abstract:

    It has recently been found the graphene oxide (GO) aggregates form in Cement Paste due to the chemical cross-linking of calcium cations. Therefore, the effects of GO addition on the properties of Cement based materials should be dependent on the properties of GO aggregates rather than GO nanosheets. In this study, GO aggregates were first characterized by particle size measurement. Then, the effects of GO aggregates on the degree of hydration, sorptivity, and tensile strength of Cement Paste were investigated. The aspect ratio of GO aggregates is much larger than that of the original GO nanosheets. Compared to Plain Cement Paste, the increase of non-evaporable water content of the Cement Paste was found to be very limited, around 1.17% and 3.90% for Cement Pastes containing 0.02% and 0.04% by weight GO, respectively. The sorptivity of Cement Paste, especially the secondary sorptivity, was notably reduced for GO incorporated Cement Paste. The tensile strength was significantly improved by GO aggregates. Incorporation of 0.04% by weight GO increased the tensile strength by 67% compared to that of Plain Cement Paste.