Dimensional stability study in carbon fiber cement composites using carbonated water and with the aid of sodium bicarbonate

• Grant number: 17/10123-3
• Support type: Scholarships in Brazil - Post-Doctorate
• Effective date (Start): July 01, 2017
• Effective date (End): January 31, 2018
• Field of knowledge: Engineering - Civil Engineering - Construction Industry
• Cooperation agreement: ANR
• Principal researcher: Holmer Savastano Junior
• Grantee: Valdemir dos Santos
• Home Institution: Faculdade de Zootecnia e Engenharia de Alimentos (FZEA). Universidade de São Paulo (USP). Pirassununga , SP, Brazil
• Associated research grant: 12/51467-3 - Agroindustrial wastes and their potential use as appropriate materials for housing and infraestructure (Agrowaste), AP.TEM

Abstract

An important problem on fiber cement industry is the edge cracking due to the effect of porosity and pore size distribution on shrinkage process. The accelerated carbonatation increase the content of calcium carbonate (CaCO3) and consume the calcium hydroxide (Ca(OH)2), and other hydrated calcium phases (depending on the carbonatation conditions), substantially changing the microstructure of the cement matrix. The effectiveness of accelerated carbonation in fiber cement leads to the volume stabilization of the composite by the control of drying shrinkage and porosity, furthermore pH is reduced and the prejudice of the fiber in fiber cement performance at long term is minimized. However, the challenge is the control of the CO2 gas and its application in large scale. Moreover, the use of gasified water instead of water in the cements hydration process can solve part of this challenge because it is easily applied in industry by the technical expertise used especially in soft drinks company as "benchmarking". A second pathway to carbonate the fiber cement is through the use of sodium bicarbonate, which is solid and does not release gas (challenge Pointed when the sparkling water use). Thus, the aim of this study is to evaluate the potential of accelerated carbonatation in cement using gasified water and in composites based on Portland cement and analyze the drying shrinkage that occurs on this composite, thus contributing for understanding of the Dimensional variation in fiber-cement For this, chemical and morphological characterizations will be performed in composites by the following analysis: X Ray Diffraction (XRD), Calorimetry, Scanning Electron Microscope (SEM), Thermogravimetry (TGA), Differential Scanning Calorimeter (DSC), X-ray Computed Tomography (XRCT), Mercury Intrusion Porosimetry (MIP) and Fourier Transform Infrared (FTIR). The composites will be analyzed too by physical characterization (water absorption, dimensional variation and bulk density) and mechanical (modulus of rupture, modulus of elasticity, yield and specific energy) after 28 days of wet curing and also after 200 cycles of accelerated aging soaking and drying. It is hoped that this research proposes an application for these carbonated materials, in order to generate a fiber cement with high dimensional stability for the use in industry. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

DOS SANTOS, VALDEMIR; DENZIN TONOLI, GUSTAVO HENRIQUE; MARMOL, GONZALO; FRIAS, MOISES; SAVASTANO JR, HOLMER. Monitoring the dynamics of Portland cement hydration through photoluminescence and other correlated spectroscopy techniques. CONSTRUCTION AND BUILDING MATERIALS, v. 252, AUG 20 2020. Web of Science Citations: 0.

DOS SANTOS, VALDEMIR; DENZIN TONOLI, GUSTAVO HENRIQUE; MARMOL, GONZALO; SAVASTANO, JR., HOLMER. Fiber-cement composites hydrated with carbonated water: Effect on physical-mechanical properties. CEMENT AND CONCRETE RESEARCH, v. 124, OCT 2019. Web of Science Citations: 0.