Estudio fisicoquímico en tuberías de hormigón en agua con pH alcalino elevado

Abstract

The aim of this work was to study of concrete pipes behavior exposed to residual water with alkaline pH. For this purpose, samples of 0,04 x 0,04 m of rectangular section and 0,6 m of length, it was extracted to concrete pipes provided by "Prefabricados del Austro". this samples were submitted to pH 9, 10 and 13 aqueous formulations. Test was along of 90 days and carrier out measurements of bend strength, chlorides and sulfates quantities, carbonation progression and porosity of the pipes.

The analysis for the physical tests was carried out in the Soil Laboratory of the Faculty of Engineering and for the chemical analyzes, the tests were carried out in the Laboratory of Bromatology and Reactors Engineering and Catalysis of the Faculty of Chemical Sciences of the University of Cuenca.

Samples exposed to pH 9, 10 and 13 was shown values from 0,360 to 1,021% of sulfates, and 0,0214 to 0,061% to chlorides, respectively. The highest sulfates percentage, such as chlorides was found at 90 days and pH 13

On the other hand, the results show a reduce drastically the value of bend strength for samples at pH 13. these values were between 11,029 MPa and 8,078 MPa at 90 days of exposure. Furthermore, the porosity of the sample obtained in base to adsorption-desorption isotherm were submitted to a coherence test, before to determine the surface area by means of the method BET. The analyzed solid has a surface area of 20,89 m2/g and this was associated with the presence of macropores in the samples.