Effect of Moisture and Additive on Radon Exhalation Rate from Concrete

Building materials are significant contributor of indoor radon after the soil. The indoor radon level depends upon the radon flux coming out from wall, ceiling and roofs of the dwellings. The radon flux from the wall that in most cases is concrete depends upon many factors like radium content, porosity, moisture, composition of mix design for construction of concrete and age of concrete. The present work is a study of effect of various factors on the radon exhalation rate from concrete. The measurement of radon exhalation rates from the concrete was determined by active technique using continuous radon monitor. The results show that the radon exhalation rate decreased with decrease of porosity of concrete and increase of moisture content after a particular value. The various additives like silica fume and fly ash may cause the decrease of radon exhalation up to optimum value, after that it increases. The radon exhalation rate also varied with age of concrete.