Elaboración de algoritmos en Matlab para calcular la tasa de exhalación de radón del concreto, usando la técnica de cámara cerrada

Abstract

The research project aimed to develop an algorithm presented in a graphical interface developed in MATLAB AppDesigner, which allows the calculation of the radon-222 surface exhalation rate of materials, using the method of linear adjustment of experimental data, for which the closed chamber technique consisting of a tempered glass chamber of 125 litres and a scintillation detector interfaced with the Pylon AB7 monitor was used, the measurements were performed for four days without interruptions at one-hour intervals. To test the algorithm, five cylindrical concrete samples were prepared using the Optimum Density method, the stone aggregates were the same for all samples and were obtained from the Sigsipamba mining area (Riobamba, Chimborazo province), while different brands of cement were used in each cylinder (Chimborazo, Guapán, Holcim, Selvalegre and Campeón) the samples were elaborated following the standards NTE INEN 1855-2 and NTE INEN 1855-1, and with the following dimensions, diameter of 15cm, height of 30cm and mass of 11.5kg on average. The chamber was characterized by means of the air leakage rate (0.0028 plus-minus 0.0002 h-1), which implies an air exchange of 0.35 litres/h, a parameter of great importance for calculating the surface exhalation rate of radon-222. The highest radon-222 surface exhalation rate was observed in the sample made with Campeón cement (2.139 plus-minus 0.128 Bq/m2h) and the lowest value in the sample constructed with Guapán cement (0.645 plus-minus 0.097 Bq/m2h), these results allow to deduce that the local materials used to manufacture cement in the north of the Ecuadorian highlands present higher radioactivity than materials from the south.