Adição de cinza do bagaço da cana-de-açúcar como finos no concreto autoadensável: estudo do ataque por sulfatos

Abstract

Over the past few years, Brazil has become the world's largest producer of sugarcane, sugar and ethyl alcohol. As a by-product of this industry, sugarcane bagasse ash is generated, resulting from the process of generating energy through the burning of sugarcane bagasse. Still without an adequate destination, researchers are seeking to better ways of harnessing to solve the problem of the destination of the by-product in issue. Research in the field of construction technologies arised in contribution to this topic, suggesting the incorporation of sugarcane bagasse ash into concretes. Self-Compacting Concrete has also been studied in research of this genre, given that the spread of its advantages of use has become increasingly large in developed countries. From the emergence of a new concept of technology, “the incorporation of sugarcane bagasse ash into Self-Compacting Concrete”, come out the need for quality control, performance, durability and shelf life. In terms of durability, internal and external chemical agents are considered as the responsible for the degradation of the concrete. External chemical agents may be concentrated in aqueous solution, as the case with sulphate salts. In view of these premises, the main objective of this research was the evaluation of the Self-Compacting Concrete regarding the resistance to the attack by sulfates when partially replaced the Portland Cement by the sugarcane bagasse ash. The mixes used in this research followed the parameters already established and studied by Molin Filho (2012), since the data generated in the author's work were compared to the data obtained in this study and served as basis. In response, the mechanical property of compressive strength reach the expectations proposed by the author. Confirmed the compatibility of the properties and sanity of the specimens produced in this work, it was proceeded for the analysis of water absorption and the behavior against the attack of sulfates. It was concluded that, in the first test, the mix containing sugarcane bagasse ash presented a more critical situation, but within the standards considered the best in respect of the quality and durability of the concrete. In the second test, it can be concluded that the rate of reduction of the compressive strength of concrete immersed in solution containing sulfates, when compared, presented similar behavior. In general, the results obtained were positive, since, although the incorporation of the material did not contribute to avoid the chemical aggression, it does not prejudice in a way to be considered. Moreover, the environmental and economic benefits inherent in the incorporation make this technology advantageous.