Utilização de cimento álcali-ativado para produção de cobogó

Abstract

Thermoelectric and steel plants are responsible for a significant generation of waste in their activities, with mineral coal ashes and metallurgical slag, respectively, the main waste materials of these industries. Such materials have the potential to replace Portland cement, either as a supplementary cementitious material or as a raw material for other types of binders, such as alkali-activated cement, which is obtained by combining materials rich in aluminosilicates and alkaline activators. In this sense, mineral coal ash, fly ash and bottom ash, as well as steelworks slag, can be used as a source of aluminosilicates to obtain alkali-activated materials. However, there are still few studies focused on the application of this type of cement in the production of artifacts for civil construction. Therefore, the objective of this study is to evaluate the feasibility of applying alkali-activated cement for the production of cobogó. For this purpose, the fresh and hardened properties of mortars produced with alkali-activated cement composed of fly ash, heavy ash and Basic Oxygen Furnace (BOF) steel slag were evaluated as precursors and sodium hydroxide and sodium hydroxide as activators. sodium sulfate. These mortars were used to produce blocks typically used in hollow walls. 03 mixes of mortar were produced varying the composition of the precursors in binary and ternary cements. In the fresh state, the mortar samples produced were submitted to the consistency and plasticity test. In the hardened state, tests were carried out on the cobogós axial compression strength, flexural tensile strength and residual strength after high temperatures (800oC) of the specimens. In view of the results obtained, it can be seen that the mix composed of fly ash and BOF slag showed the best workability among the mixes tested. The cobogós resulting from the aforementioned trait obtained the highest compressive strength equal to 4.65 MPa. All traces remained intact after 800°C in the residual strength test. Therefore, the feasibility of applying alkali-activated cement based on fly ash, heavy ash and BOF slag for the production of non-structural hollow blocks is attested.