Assessment of natural radioactivity and radiation hazards owing to coal fly ash and natural pozzolan Portland cements

The natural radioactivity in coal fly ash and natural pozzolan Portland cement samples produced in Spain was measured by gamma spectrometry. Activity concentrations of 226Ra, 232Th and 40K ranged from 15.7 to 88.3 Bq kg−1, from 12.8 to 81.0 Bq kg−1 and from 37.0 to 678.0 Bq kg−1, respectively. The radiological hazards samples owing to the mentioned natural radioactivity were inferred from determinations of the activity concentration index, I, absorbed dose rate, Dext, and annual effective dose, Ep, which falls within 0.20 mSv to 0.87 mSv (coal-cement) and 0.18 mSv to 0.50 mSv (pozzolan-cement) (≤ 1 mSv, threshold criterion). Therefore, these cements are proper to be used for building purposes as result of their radiological assessment.