Comparação das propriedades no estado endurecido de dois traços de concreto: convencional e autoadensável

Abstract

The importance of the continuous improvement of the civil construction sector, objectifying the increase of the quality of the reinforced concrete structural elements and solving the problems related to the availability of work force on the building sites, highlighting the concrete with self-compacting characteristics, developed in Japan, in the mid 80’s. Presenting three essential characteristics: flowability, passing ability and segregation resistance, this concrete presents a series of advantages, like the amount of used work force, the increase of quality of the structural elements, the easiness and launching rapidity. However, to achieve these characteristics, one factor is indispensable: the use of fines. These materials, called additions, control the negative effects of segregation and bleeding that are susceptible to appear on the fluid state of concrete. Additionally, the control of the creation and application of new materials are important factors, helping to understand its characteristics and suitable applications. In that context, the present paper objectifies the comparison of the properties of a selfcompacting concrete with a conventional concrete, in their solid state. Therefore, a self-compacting concrete is developed making use of materials available on the region of the city of Toledo-PR and using fly ash as the powder. This fluid concrete is used as a base to obtain two conventional concrete traces, finally being subjects of comparison. Thus, it is evident that the self-compacting concrete performs better than the other concrete subjects, mainly on the parameters of tensile strength, compressive strength and elasticity module, once its number of holes and absorption ratio are reduced. Lastly, the microstructure of the concretes are compared, making use of scanning electron microscopy to analyze the three concretes produced in this paper.