Resumen

VELEZMORO CAPALDO, Ana C; BLANCO, Henry A  y  PENUELA, Cesar. Influence of nitrate present in the water mixing in the physical properties of concrete. Rev. Fac. Ing. UCV [online]. 2014, vol.29, n.2, pp.61-67. ISSN 0798-4065.

The development of concrete with no potable mixing water has been studied in several countries, concluding that it is possible to obtain good quality concrete, even when using treated wastewater. In Venezuela, the results when treated wastewater was used were not expected, since the compressive strength between mixtures did not follow the Venezuelan standard, which sets a maximum difference of 10%. By comparing the water quality parameters in the different studies, it was found that nitrate was the different constituent containing the mixing water, which is why it was proposed to verify the behavior of concrete is modified by its presence. To this aim, potassium nitrate was added to drinking water to equalize the amount of nitrates in the treated wastewater. At two concrete mixtures were made with type tests to characterize their physical properties: setting time, absorption, erosion, weighing, ultrasound and compressive strength. We conclude that the only property of the concrete that is modified by the presence of nitrate and / or potassium in the mixing water is the resistance to compression, with a difference of 15%, possibly as the result of the decalcification due to the phenomenon of leaching. The workability, durability and homogeneity of concrete showed no significant differences. Therefore it is suggested to adjust the mix design when the presence of nitrate and potassium in the mixing water in concentrations is greater than 10 and 18 mg/l respectively, to ensure the desired resistance to compression of concrete.

Palabras clave : Mixing water; Nitrate; Concrete leaching; Physical properties of concrete; Compression strength.