Influence of Neutralization Accelerated by the Soak Method on the Radon Exhalation of Cement-based Materials.

Radon is considered a significant contaminant that affects indoor air quality. Neutralization is one of the most important environmental factors in changing pore structure of cement-based materials that may release radon. Therefore, it is necessary to study the radon exhalation of cement-based materials impacted by neutralization, which is extremely lacking. Some concrete blocks were accelerated to neutralization by soaking in sodium bicarbonate solution, and the radon activity concentrations over the blocks were measured to investigate the effect of neutralization on radon exhalation. Controlled experiments were conducted with blocks in the initial dry state and soaked in pure water. The results show that the radon activity concentration exhaled from block is promoted by neutralization, and the promoting role of water is quite limited. The radon surface exhalation rate increases by increasing the sodium bicarbonate solution concentration from 0.5% to saturation.