Ref.: MceCge11-004
Apresentador: Thiago Ricardo Santos Nobre
Autores (Instituição): Nobre, T.S.(Universidade de São Paulo); Baldusco, R.(Instituto de Pesquisas Tecnológicas); Mesquita, J.A.(Universidade de São Paulo); Pereira, V.M.(Universidade de São Paulo); Quarcioni, V.A.(Instituto de Pesquisas Tecnológicas); Vieira-Coelho, A.C.(Universidade de São Paulo); Angulo, S.C.(Universidade de São Paulo);
Resumo:
Partial replacement of clinker in Portland cement with blast-furnace slag is advantageous from both technical and environmental perspectives. However, there are limited studies conducted on the characterization of the formed phases and the rheological behavior in situ. The objective of this research was to monitor the hydration of blast-furnace slag cement in situ using X-ray diffraction (XRD) at the XRD/LNLS beamline. The diffractogram collection time was approximately 180 seconds and X-ray wavelength of 1.033 Å (12 keV), which was determined by the standard reference material (silicon — NIST SRM 640d). The analysis of the consumption of anhydrous phases and hydrated cement products was conducted using HighScore Plus software (version 4.9), based on data from diffractometric sheets provided by COD (Crystallography Open Database). To achieve dispersion, a dispersing additive based on polycarboxylate-based was used. The analysis revealed the presence of alite, belite, calcite, quartz, periclase, and dolomite. Portlandite and hydrotalcite were also detected in the anhydrous cement. Gypsum, aluminate, and brownmillerite were consumed in the first 10 minutes and ettringite hydration evolved after 3 hours. The peak of alite the most significant reduction after 11 hours, while gypsum and brownmillerite exhibited reductions after 18 and 20 hours, respectively. Additionally, the paste’s elastic storage modulus of was evaluated during the consolidation process, indicating that the fluid–solid transition is not only influenced by the formation of phases but also by the physical interaction of the constituent materials, thereby affecting the paste’s hardening process.