| Autor: |
Istuque DB; MAC-Grupo de Pesquisa em Materiais Alternativos de Construção, Universidade Estadual Paulista (UNESP), Campus de Ilha Solteira, Av. Brasil Sul, 56-Centro, Ilha Solteira 15385-000, SP, Brazil., Sanches AO; MAC-Grupo de Pesquisa em Materiais Alternativos de Construção, Universidade Estadual Paulista (UNESP), Campus de Ilha Solteira, Av. Brasil Sul, 56-Centro, Ilha Solteira 15385-000, SP, Brazil., Bortoletto M; MAC-Grupo de Pesquisa em Materiais Alternativos de Construção, Universidade Estadual Paulista (UNESP), Campus de Ilha Solteira, Av. Brasil Sul, 56-Centro, Ilha Solteira 15385-000, SP, Brazil., Malmonge JA; MAC-Grupo de Pesquisa em Materiais Alternativos de Construção, Universidade Estadual Paulista (UNESP), Campus de Ilha Solteira, Av. Brasil Sul, 56-Centro, Ilha Solteira 15385-000, SP, Brazil., Soriano L; Institute of Concrete Science and Technology (ICITECH), Universitat Politècnica de València, 46022 València, Spain., Borrachero MV; Institute of Concrete Science and Technology (ICITECH), Universitat Politècnica de València, 46022 València, Spain., Payá J; Institute of Concrete Science and Technology (ICITECH), Universitat Politècnica de València, 46022 València, Spain., Tashima MM; MAC-Grupo de Pesquisa em Materiais Alternativos de Construção, Universidade Estadual Paulista (UNESP), Campus de Ilha Solteira, Av. Brasil Sul, 56-Centro, Ilha Solteira 15385-000, SP, Brazil.; Institute of Concrete Science and Technology (ICITECH), Universitat Politècnica de València, 46022 València, Spain., Akasaki JL; MAC-Grupo de Pesquisa em Materiais Alternativos de Construção, Universidade Estadual Paulista (UNESP), Campus de Ilha Solteira, Av. Brasil Sul, 56-Centro, Ilha Solteira 15385-000, SP, Brazil. |
| Abstrakt: |
The aim of this study was to use the electrical impedance spectroscopy technique (IS) to carry out a systematic study on the mechanism of metakaolin geopolymerization for up to 7 curing days. The study was developed on two batches of metakaolin (MK), and their reaction processes were compared. Interpretative fundamental elements were developed based on the effective electrical conductivity curves regarding the metakaolin geopolymerization. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were previously carried out and used to interpret and validate the electrical behavior of the fresh and hardened MK-based geopolymer pastes. The results highlighted the sensibility of the impedance technique to the identification and description of the MK geopolymerization process, as well as the changes resulting from even slight variations in the metakaolin composition. Furthermore, this indicated that the geopolymerization process in highly alkaline solutions could be divided into seven stages, including the processes of dissolution, nucleation, precipitation and formation of the gel and, eventually, the retraction/microcracks constitution. Late dissolution processes could be observed during the more advanced stages and were attributed to particles not being fully hydrated. |
