The Experts below are selected from a list of 92637 Experts worldwide ranked by ideXlab platform

Peter K Liaw - One of the best experts on this subject based on the ideXlab platform.

Feng Xing - One of the best experts on this subject based on the ideXlab platform.

  • evolutionary trace for early hydration of cement paste using Electrical Resistivity method
    Construction and Building Materials, 2016
    Co-Authors: Biqin Dong, Jianchao Zhang, Yanshui Wang, Guohao Fang, Yuqing Liu, Feng Xing
    Abstract:

    Abstract Setting time and early strength of cement are two key parameters to the early hydration of cementitious materials. The two indexes are qualified via traditional Electrical method in the past, but several defects still remain in traditional Electrical methods, Electrical Resistivity measurement is put forward to study the two key parameters in this paper. A relationship between setting times (including initial and final setting time) and the electrodeless Resistivity has been discussed, aiming to establish a rapid testing method which could predict setting time of cementitious materials. Furthermore, Electrical Resistivity measurement and standard compressive strength test has been studied and the experimental results show that the cement paste matrices with higher water cement ratio present the lower Electrical Resistivity value. A linear relation is established between the standard compressive strength of cements at 1 d and the Resistivity of the pastes at 24 h, which can demonstrate the Resistivity and the standard compressive strength have a close corresponding relationship, and the Resistivity curve of cement and the strength development curve has the same trend. So the standard compressive strength of cements could be predicted by Electrical Resistivity curve.

Taehwan Kim - One of the best experts on this subject based on the ideXlab platform.

  • using the particle model to predict Electrical Resistivity performance of fly ash in concrete
    Construction and Building Materials, 2020
    Co-Authors: Shinhyu Kang, Zane Lloyd, Tyler M Ley, Taehwan Kim
    Abstract:

    Abstract The Electrical Resistivity performance of fly ash in concrete is not easy to predict due to the diverse sources of fly ash and their varying reactivity. Electrical Resistivity gives direct evidence of the rate of corrosion within the concrete and provides indirect clues into the fluid transport into the material. This paper aims to develop predictive models for the Electrical Resistivity of fly ash concrete by applying the Particle Model. The Particle Model rapidly examines individual fly ash particles without human intervention and is used to derive predictive models for 20% and 40% fly ash replacement levels in concrete at seven different periods of hydration. The R-squared values of predictive models in the Particle Model show significant improvement over using the classification method based on Class C and F for both fly ash replacement at all investigated time periods. The derived predictive models are able to accurately estimate the Electrical Resistivity within +/- 10% for 80% of all measurements at 20% fly ash replacement and within +/− 10% for 75% of all measurements at 40% fly ash replacement. These investigations provide important insights into how the Particle Model can help predict the Electrical Resistivity of fly ash concrete even at different mixtures and hydration times.

Denys Breysse - One of the best experts on this subject based on the ideXlab platform.

  • characterisation of fibres distribution in a steel fibre reinforced concrete with Electrical Resistivity measurements
    Ndt & E International, 2008
    Co-Authors: Jeanfrancois Lataste, M Behloul, Denys Breysse
    Abstract:

    Abstract Steel fibre reinforced concrete (SFRC) is a new material allowing innovative projects for concrete structures. Such structures are designed using assumptions on the material fabric. Checking these assumptions requires, according to recommendations, coring and mechanical testing of samples. Non-destructive assessment, if validated, would provide an interesting alternative, making the checking process easier, quicker and less expensive. Blind tests in laboratory compare Electrical Resistivity measurements obtained with a four-probes square device, to visual analysis during pouring. After having defined a measurement process, the representativity of Electrical Resistivity values is assessed by analysis of measurements on eight slabs. Electrical Resistivity allows the identification of a high or low Resistivity axis, which gives the local orientation of steel fibres. The calculation of Electrical anisotropy gives an indication of the “intensity of fibres orientation” in each area. In this article, the complete analysis process is detailed on two slabs which have been casted according to two different fibres distributions. These tests confirm the ability of Electrical Resistivity method to provide data on steel fibres within concrete, via a non-destructive way.

Akira Endo - One of the best experts on this subject based on the ideXlab platform.

  • theoretical modeling of Electrical Resistivity and seebeck coefficient of bismuth nanowires by considering carrier mean free path limitation
    Journal of Applied Physics, 2017
    Co-Authors: Masayuki Murata, Atsushi Yamamoto, Y Hasegawa, Takashi Komine, Akira Endo
    Abstract:

    In this study, the Electrical Resistivity and Seebeck coefficient of bismuth nanowires, several hundred nanometers in diameter, are calculated using the Boltzmann equation in the relaxation time approximation. The three-dimensional density of states and properties of single-crystalline bulk bismuth, such as carrier density, effective mass, and mobility, are used in the calculation without considering the quantum size effect. The relaxation times of the electrons and holes are calculated using Matthiessen's rule considering the carrier collisions at the wire boundary. The temperature, crystal orientation, and diameter dependence of the Electrical Resistivity and Seebeck coefficient are investigated. The calculation demonstrates that the Electrical Resistivity increases gradually with decreasing wire diameter, and the temperature coefficient of the Electrical Resistivity varies from positive to negative at low temperatures for thin wires with diameters less than approximately 500 nm. The diameter dependence...