Characterization of pottery kilns ash for application on pozzolanic cement

The characterization of materials with potential for cement replacement it is an important mitigation of environmental impacts caused by the construction industry. Pozzolanic materials can improve the properties of concretes in the hardened state. However, in order for these properties to be active in the materials, they must meet the requirements, in Brazil, regulated by ABNT NBR 12653, presenting specific physical, chemical and mineralogical characteristics. Pottery kiln ash is the main solid residue produced by the industries producing red ceramics. Presidente Epitácio city, SP, has these industries as a highlight in its economy. This work performed tests of fluorescence and X-ray diffraction for chemical and mineralogical characterization. For physical characterization, laser granulometry and standardized tests were performed by ABNT NBR 5751 and 5752 . Mortars with 10%, 20% and 30% of the mass of cement replaced by ash were also tested for compression, cured for 7, 28 and 91 days. The results of tests performed showed a material that does not meet all the standardized demands, having positive results only in the particle size and index of pozzolanic activity with Portland cement, by ABNT NBR 5752. The results of the tests suggest the necessity of new tests for thermal activation of the material and, also to allow it is incorporation into the production of composite cements with potential use in pastes, mortars and concretes. (author)