Impact of hydration reactions on microstructural development and evolution of rheological properties of Portland cement suspensions

• Grant number: 19/03254-0
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: June 01, 2019
• End date: May 31, 2023
• Field of knowledge: Engineering - Civil Engineering - Construction Industry
• Principal Investigator: Rafael Giuliano Pileggi
• Grantee: Marcel Hark Maciel
• Host Institution: Escola Politécnica (EP). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The monitoring of the rheological properties of cementitious components over time is essential in several industrial sectors, since the microstructure in formation in the reactive materials is altered as a function of the production of the hydrated compounds, with changes in volume, area and surface charges, agglomeration potential/coagulation, etc. Considering that there is a tendency to produce cementitious materials with increasing mineral content of different types, reduction in the amount of kneading water, use of organic admixtures, among other factors, the evaluation of the rheological behavior becomes more complex and essential for the processing and performance. Therefore, the objective of this research project is to evaluate the impact caused by the microstructural transformations resulting from Portland cement hydration reactions on cement paste properties in the first hours of hydration. Suspensions with Portland cement and limestone filler with dilution and filler functions will be evaluated at different temperatures. The changes in particle morphology and microstructure will be monitored by various characterization techniques, such as granulometric/morphological distribution tests, N2 adsorption isotherms, backscattered electron diffraction in scanning electron microscopy, nuclear proton magnetic resonance (1NMR) and 3D X-ray microtomography. The results obtained will be used in conjunction with the force diagrams constructed from the suspension properties, aiming at the refinement of the yield stress (YODEL), viscosity (natural interference) and consolidation (build-up) models. (AU)