EFFECTIVE MIX DESIGN OF HEAVYWEIGHT CONCRETE FOR GAMMA-RAY SHIELDING AND MECHANICAL PROPERTIES OF CONCRETE

Abstract

Utilization of heavyweight concrete as radiation shielding has bringing benefits not only in energy for nuclear power plant, but also accelerators in medical and in industrial, then in radiation sources for agricultural field. The lack of experiment related to structural member in heavyweight concrete is a reason in performing this study. Concrete that were resulted for this study restricted to barite (BaSO4) as heavy material that highly available in Thailand. Modification experiment was expected to achieve effective barite concrete mixture using local material from Thailand. This experiment will evaluate mechanical properties of barite concrete, attenuation of gamma-ray, and barite reinforced concrete beam as parameter to determine the effectiveness of the mixture. 20 different barite concrete mixtures with 2 variations of w/c ratios and 4 classifications of replacement percentage aggregate will be examined. Using Cesium-137 and Cobalt-60 energy sources, linear attenuation coefficient (µ) of barite concrete will be measured at two different energies which are 0.662 MeV and average 1.250 MeV (combination 1.173 MeV and 1.332 MeV), respectively. We concluded that replacement coarse aggregate with normal aggregate deemed most advantageous in term of workability of concrete. In relation with provision standard, ACI 349-06 equation is not applied for barite concrete due to underestimated. Contribution replacement normal sand in mixture is affected in stiffness of the beam. Moreover, percentage barite in the mixture had main role in ductility factor and not correlated with number of w/c ratio and type of replacement aggregate in the mixture.