An autoclaving treatment for disks made of neat Portland cement and cement with 5% silica fume hardened pastes was carried out to obtain suitable shield blocks for gamma radiation sources. The attenuation parameters such as the total linear attenuation coefficients, the mean-free-paths and the half-value thickness for different thicknesses at various periods of autoclaving were obtained. It was found that the attenuation by the neat cement disks autoclaved for 12 h and of 13.8 cm thickness and the disks of cement with 5% silica fume autoclaved for 6 h and of 12.9 cm thickness were the same and identical to that obtained by 3 cm thick sheets of lead. These results are interpreted by measuring the bulk density of the samples and are supported by measuring the compressive strength for the hardened samples. (C) 1998 Elsevier Science Ltd. All lights reserved. [References: 8]
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