Influence of cellulose pulp on the hydration followed by fast carbonation of MgO-based binders

Author(s)

Marmol, Gonzalo ^[1] ; Mattoso, Luiz ^[2] ; Correa, Ana Carolina ^[2] ; Fioroni, Carlos A. ^[1] ; Savastano, Jr., Holmer ^[1]

Affiliation

^[1] Univ Sao Paulo, Fac Anim Sci & Food Engn, Dept Biosyst Engn, Duque Caxias Norte St 225, BR-13630000 Pirassununga, SP - Brazil

^[2] Embrapa Instrumentat, Natl Nanotechnol Lab Agribusiness, 15 Novembro St 1452, BR-13560979 Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: JOURNAL OF CO2 UTILIZATION; v. 41, OCT 2020.
• Web of Science Citations: 1

Abstract

This study aims at assessing the potential use of cellulose pulp in MgO-water slurries with potential for precast composites. These systems for composites applications envisage encapsulating CO2 when exposed to fast car-bonation. The effect of cellulose fibers was evaluated on samples after the drainage of MgO-cellulose-water slurries. Different cellulose mass fractions were added into MgO-water suspensions - up to 30 wt% - to study the MgO hydration during the first 96 h. Afterward, the carbonation of the hydrated products for 6 and 12 h was evaluated. The addition of cellulose, after hydration, increases the sample porosity, where Mg(OH)(2) is the main crystalline phase and only minor traces of unreacted MgO are found. MgO-H2O systems after hydration do not present any binding capacity given the low density and high apparent porosity of the clusters. However, XRD and TG analyses show that exposing samples to a rich CO2 environment promotes the formation of nesquehonite (MgCO3 center dot 3H(2)O), which significantly reduces the porosity induced by the cellulose hygroscopy. This reduction in porosity is greater for samples with cellulose fibers because of the greater content of nesquehonite produced in samples with cellulose. Besides, cellulose fibers are covered with nesquehonite nanocrystals after carbonation. By adding cellulose to water-MgO suspensions yields lighter products with promising potential for fiber-cement applications. Moreover, the addition of cellulose contributes to the encapsulation of CO2 in building materials through the Mg(OH)(2) carbonation. (AU)

• FAPESP's process: 18/20913-4 - CO2 encapsulation in cementitious composites based on Mg hydrated compounds reinforced with cellulosic fibers
• Grantee: Gonzalo Mármol de Los Dolores
• Support Opportunities: Scholarships in Brazil - Post-Doctoral