Determination of shielding Effectiveness of Concretes with different Aggregate and cement composition

The shielding effectiveness of concretes with different aggregate and cement composition was determine by shielding Co-60 gamma radiation source at center for energy research and training (CERT), Ahmadu Bello University Zaria with block concretes that contain aggregate 5.00 mm, 10.00 mm and 15.00 mm respectively. A concrete with thickness of 0.0762 m with dimension of 0.30 m x 0.30 m was formed from each of the aggregates with equal volume of sharp sand and cement. The result revealed the calculated mean free path (MFP) with values within a range of (0.033 to 0.070) m for samples DG (Dangote) and BU (BUA), mass attenuation coefficient (MAC) and half value layer (HVL) values within a range of (1.9 to 2.75) x 10-3 m2/kg and (0.023 to 0.049) m respectively. This shows that samples DG1, DG2 and DG3 have better shielding ability due to its lower MAC, MFP and HVL compared to samples BU1, BU2 and BU3.