Análise das propriedades de argamassas no estado fresco e endurecido utilizando resíduo de caulim.

Abstract

The search for sustainable products has become an important factor to the future of construction due to the limited amount of natural resources. For this reason, there are many studies about the use of waste in building materials. Among the several studies about wastes, there are those from kaolin production. Kaolin is a rock composed by kaolinite, which is used in various industrial sectors of the country. The extraction and processing of this mineral are waste generators, that are often unplanned discarded. There are studies on the potential of kaolin residue and its applicability in alternative materials in the production of concretes, blocks and mortars. In order to contribute to this research, this paper aims to evaluate the influence of kaolin residue on properties in the fresh and hardened state of mortars. For this, two types of kaolin residues were studied separately: the fine (RF), evaluated as hydrated lime substitution, and the coarse (RG), as fine aggregate. The traces chosen for this study were 1:1:6 and 1:6 in volume, modifying the residue ratio by 50% and 100% with conventional materials. There were also used in the mortars plasticizer additive and metakaolin (MC). The methodology consisted of characterizing the starting materials, physical properties (unit mass, specific mass and particle size), obtaining data on chemical (x-ray fluorescence) and mineralogical (x-ray diffraction) composition. In addition, the properties of fresh mortars (consistency index, fresh mass density and incorporated air content) and hardened properties (bulk density, compressive strength and capillary water absorption) were evaluated. The results showed good mechanical performance and a higher kneading water consumption of the mortars constituted by residue. The use of plasticizer additive contributed to the reduction of the water/cement factor and to the increase of compressive strength compared to the reference mortars.