ASSESSMENT OF THE NATUAL RADIOACTIVITY AND RADIOLOGICAL HAZARDS IN LAO CEMENT SAMPLES.

The radioactivity concentrations of Ra-226, Th-232 and K-40 natural radionuclides in Lao Portland cement samples were measured using a gamma-spectrometry with a HPGe detector. The activity concentrations were found to vary from 28.32 +/- 2.23 to 65.50 +/- 2.83 Bq kg(-1) with a mean value of 41.12 +/- 2.44 Bq kg(-1) for Ra-226; from 7.25 +/- 2.00 to 44.01 +/- 2.45 Bq kg(-1) with a mean of 16.60 +/- 2.37 Bq kg(-1) for Th-232 and from 49.19 +/- 4.27 to 196.74 +/- 4.75 Bq kg(-1) with a mean of 141.48 +/- 4.50 Bq kg(-1) for K-40, respectively. The radiological parameters were estimated to assess the potential radiological hazard including radium equivalent activity, total external absorbed dose rate in outdoor air at 1 m above the earth's surface, the annual effective dose, the gamma and alpha-indices were calculated using the activity concentrations of Ra-226, Th-232 and K-40. The results obtained in this study show no significant radiological hazards arising from using Lao Portland cement for building construction.