a b s t r a c tThe decrease in concrete resistance and the expansion generated in reinforced concrete structures by direct exposure to fire at 400°C maximum temperature serves as the basis for the present research. The aim is to improve these problems by the addition of steel fibers or of polypropylene fibers in concrete.From the results analysis of compression fracture tests on cylindrical concrete specimens, it can be concluded that concrete with addition of polypropylene fibers or steel fibers are a good alternative to traditional concrete, because both its strength, and its behavior in case of fire are improved, delaying the appearance of fissures and explosive concrete spalling.

Resumen En este trabajo se realiza un estudio sobre el fondo de la cuestión de la técnica aplicada a la mejora de la eficiencia. Con este punto de partida podemos profundizar en las claves en el uso de los recursos para la eficiencia energética y concretarlas en un modelo de actuación que ilustra una aproximación sistémica al campo del aprovechamiento de la energía, y que reintegra a la edificación su valor intrínseco como medio eficiente de gestión de la energía y su transformación. Abstract This paper presents a study on the heart of the matter of the technique applied to improving efficiency is performed. With this starting point we can deepen the keys in the use of resources for energy efficiency and achieve them in a role model illustrating a systemic approach to the field of energy efficiency, and reintegrated into building its intrinsic value as efficient means of energy management and processing.