Análise da resistência à compressão axial do concreto, com cinza da casca do café

The search for alternative methods in civil construction, that aims the decrease in consumption of finite materials and less negative impacts to the environment is increasingly present in field activities and, everyday, several researches are developed for this purpose. In order to contribute to a sustainable economy, that generates less environmental impact, this work proposes the determination of a trait, through laboratory reseach, from concrete, replacing part of the cement (in mass) with burnt coffee husk. A lot of researches with other alternative materials, like ashes made from rice husk, tire rubber and residue obtained from construction and demolition brought satisfactory results to the physical performance of concrete. Based on this concept, a reference trait was determined for the concrete; however, due to the difficulty to obtain the coffee husk ashes, mortar specimens were made (from which it was extracted the coarse aggregate of the adopted trait to obtain the “mortar”) to verify the best percentage of residue to be used in making concrete specimens, thus avoiding waste of materials. From the results obtained in the mortar axial compression test, it was observed that, with a 5 % replacement from cement to ashes, there was a considerable decrease in the axial endurance. Therewith, it was determined that, it would be analyzed 2 % and 5 % replacements of ashes with respect to cement. However, through axial compression and diametral tests, it was possible to notice that the ashes showed no improvement in the strength of the concrete, therefore, not showing the same behavior as rice husk ashes in the concrete. Based in the results obtained in this work, it seems that the ash had influence such as the voids, thus, decreasing the endurance significantly.