Browsing by Author "Nshimirimana, R"

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    Appraisal of a cementitious material for waste disposal: neutron imaging studies of pore structure and sorptivity
    (Elsevier, 2010-08) McGlinn, PJ; de Beer, FC; Aldridge, LP; Radebe, MJ; Nshimirimana, R; Brew, DRM; Payne, TE; Olufson, KP
    Cementitious materials are conventionally used in conditioning intermediate and low level radioactive waste. In this study a candidate cement-based wasteform has been investigated using neutron imaging to characterise the wasteform for disposal in a repository for radioactive materials. Imaging showed both the pore size distribution and the extent of the cracking that had occurred in the samples. The rate of the water penetration measured both by conventional sorptivity measurements and neutron imaging was greater than in pastes made from Ordinary Portland Cement. The ability of the cracks to distribute the water through the sample in a very short time was also evident. The study highlights the significant potential of neutron imaging in the investigation of cementitious materials. The technique has the advantage of visualising and measuring, non-destructively, material distribution within macroscopic samples and is particularly useful in defining movement of water through the cementitious materials. © 2010 Crown Copyright published by Elsevier Ltd.
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    Appraisal of a cementitious material for waste disposal: neutron imaging studies of pore structure and sorptivity
    (Laboratoire SUBATECH, 2008-10-14) McGlinn, PJ; de Beer, FC; Aldridge, LP; Radebe, MJ; Nshimirimana, R; Brew, DRM; Payne, TE; Olufson, KP
    To characterise and to evaluate the durability, structural properties and sorptivity of a candidate wasteform for ILW and gain an understanding of the factors that control water movement through the matrix and the matrix and the resultant degradation process.
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    Water transport through cement-based barriers - a preliminary study using neutron radiography and tomography
    (Elsevier, 2009-06-21) Brew, DRM; de Beer, FC; Radebe, MJ; Nshimirimana, R; McGlinn, PJ; Aldridge, LP; Payne, TE
    In this preliminary study we use neutron radiography and tomography to examine differences in water transport through cement pastes and mortars. Bulk residual water contents and sorptivity curves determined using neutron radiography are compared with data obtained gravimetrically. In addition, macro-pore volume distributions of each sample were measured. Furthermore, it was possible to use neutron radiography to monitor the change in the mass of water when samples were dried or when water moved into the samples. The trends and absolute values of weight loss and gain obtained using both approaches are very consistent for mortars, especially when a neutron-scattering correction is applied. © 2009, Elsevier Ltd.