Usage potential of fly ash an metakaolin in cementitious materials for 3D printing

Abstract

The technology of 3D printing has been studied by different researchers, due to the possibility of producing solid objects swiftly, time reduction, labor with fewer failures the construction process. One of the challenges to be overcome is related to the development of mixtures promising. Thus, research aimed at the technology of cementitious materials is necessary to develop extrudable and sustainable mixtures. This article aimed to investigate the potential use of (FA) and (MK) in cementitious materials for application in three-dimensional printing (3D) by checking the aspects of constructibility. In the first stage, tests of normal consistency and initial and final setting time were carried out on pastes, with calcium oxide 4% and addition of (FA) and (MK) in the percentages of 8%, 10% and 15% in relation to the cement mass, in order to establish an ideal water / cement ratio. In the second stage, given a pre-determined trace of 1: 1.5, in mass, the viscosity, yield stress, extrudability and verticality tests were carried out on the cementitious materials developed in the first stage. It was observed that for the aspects related to the normal cement consistency and initial and final setting time, the paste with 15% substitution (FA) presented a longer initial setting time when compared to pastes with (MK) added. yield stress, materials with 15% substitution (FA) and without superplasticizer additive showed favorable results in the relation of the initial and final yield stress, as the mixture of 15% (MK) with 0.4% superplasticizer additive. and, therefore, they were considered promising because they were subjected to extrudability and verticality tests. Thus, it is concluded that considering the constructibility applied to prototyping, cementitious materials with 15% substitution (FA) and (MK) in relation to the cement mass present results considered relevant for the application in 3D printing.