Análisis de la degradación de varillas de construcción con protección catódica mientras están sometidas a ambientes con elevados niveles de PH

Abstract

The objective of this research project was to analyze the degradation of construction rods subjected to environments with high pH levels. For this study, rods of five diameters (8,10,12,14,16 mm) were used, with and without cathodic protection. To increase the pH of the soil (alkaline and acid), lime and potassium chloride were added, respectively a cement base of (82500 cm3) divided in the half. The soil analysis was carried out (pH, humidity, electrical conductivity and REDOX potential). Soil was placed up to the middle of the base, in each division 5 were placed without and 5 rods with cathodic protection, a voltage source (2.5V) was placed on the latter. The amount of voltage consumed by the rods was measured with a multimeter and after 30 days the rods were transferred to the laboratory to perform the metallographic test (corrosion and impurities). The results showed that both the alkaline and acid soils without cathodic protection produced corrosion in the rods. However, in this last type of soil, the corrosion rate was higher in the five types of rods (8mm: 0.0388 ipy, 10mm: 0.0273 ipy, 12mm: 0.0220 ipy, 14mm: 0.0152 ipy, 16mm: 0.031 ipy). Likewise, it was determined that the costs vary when cathodic protection is applied in an alkaline and acid soil ($2.01, $4.41). It is concluded that the alkaline soil presented a lower corrosion rate in the five rods studied, due to the conditions shown in its microstructure; and, that the costs vary depending on the type of soil where the cathodic protection was used. It is recommended to use a higher precision instrument for the proper measurement of mass loss in the specimens because the scale only indicated whole data.