Estudo do efeito da cura térmica na resistência inicial do concreto para aplicação na indústria de pré-moldados de concreto

Abstract

The construction industry compared to other sectors, can be considered late, considering the great waste of material, lack of mass production and a skilled work force with low education. The prefabrication of structural parts of precast concrete is approaching the construction of a possible industrialization. This prefabrication but may be limited when analyzed using forms for concrete. The high cost of a well as limiting the amount of times it is used daily, hinder, or even become more expensive this production. The fact that concrete has to have adequate strength so it can be hoisted is the factor that limits the deformation of the part, considering that this resistance is needed in a few hours. For this situation, the thermal curing is presented as an alternative to this difficulty of mass production. Within this context, this work presents the study of the effect of thermal curing on early strength of concrete for use in the precast industry. The goal is to get in eight hours 15 MPa compressive strength value that is referenced by the bibliography, so that the production of a factory precast can be doubled when considering the Question shapes of the pieces. For this it was necessary to compare results of concrete cured at room temperature (with temperature around 23 º C), with thermally cured concrete with maximum temperatures of 40 º C and 60 º C. For each type of curing each 32 body -specimens were molded, each test was to cure the ages of 8 and 24 hours, 7 and 28 days. In every age, was held testing compressive strength (3 body-of - evidence), traction by diametrical compression (3 body-of - evidence) and elastic modulus (2 body-of - evidence). After performing all the test described above, a statistical treatment was carried out, so that was assessed the significance of the results. The results show that 15 MPa was achieved in 8 hours to cure to a level of 60 ° C, but the statistical analysis also showed that healing with a maximum temperature of 40 ° C can be effective when analyzed characteristics of compressive strength, resistance tensile strength and modulus of elasticity.