Durability assessment of MgO-based fiber cement reinforced with lignocellulosic fibers and cured in a CO2-rich atmosphere

Author(s)

Azevedo, A. G. S. ; Baltazar, L. ; Faria, P. ; Savastano, H.

• Document type: Journal article
• Source: JOURNAL OF BUILDING ENGINEERING; v. 104, p. 20-pg., 2025-06-15.

Abstract

This study investigates the durability and performance of fiber cement composites produced from magnesium oxysulfate (MOS) matrices reinforced with lignocellulosic fibers, subjected to accelerated carbonation. The composites underwent mechanical, physical, and chemical characterization through flexural strength tests, X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) after various aging cycles. Durability was assessed via freeze-thaw, soak-and-dry, and UV exposure tests. Carbonation led to a reduction in mechanical strength, which is attributed to the reaction of CO2 with phase 5-1-7, a key component responsible for strength development. The formation of new carbonation products, confirmed by TGA and SEM, modified the physical properties of the composites. The changes in physical properties clearly demonstrate that accelerated carbonation promoted the formation of Hydrated Magnesium Carbonates (HMCs), which precipitated in voids, thereby increasing the density of the fiber cements. XRD analysis showed a reduction in the phase 5-1-7 peak intensity following CO2 exposure, corroborating the carbonation process. These results contribute to optimizing curing processes and durability treatments, enhancing the applicability of MOS-based composites in construction, particularly for prefabricated panels and non-structural walling systems exposed to different weather conditions. (AU)

• FAPESP's process: 21/04780-7 - Study of durability on cementitious composites reinforced with lignocellulosic fibers with MgO and MgSO4 matrices
• Grantee: Adriano Galvão de Souza Azevedo
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 14/50948-3 - INCT 2014: advanced eco-efficient technologies in cementitious products
• Grantee: Vanderley Moacyr John
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 24/02445-4 - Use of nucleation seeds to enhance CO2 capture and mineralization from the sugar and ethanol industry in low-carb fiber-cement
• Grantee: Adriano Galvão de Souza Azevedo
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 22/07179-5 - Durability evaluation of MOS matrix fiber cement reinforced with lignocellulosic fibers and submitted to accelerated carbonation process
• Grantee: Adriano Galvão de Souza Azevedo
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor