ICNF 2019 - 4th International Conference on Natural Fibers
The use of lignocellulosic fibers in cement based materials – challenges and achievements
Holmer Savastano – University of São Paulo, Brazil
Graduate at civil engineering at Universidade de São Paulo (USP, 1984), Brazil, doctor degree at Civil Engineering from USP (1992), and post-doctoral fellowship at Forestry and Forest Products, Commonwealth Scientific Research Industrial Organisation, Australia (FFP, CSIRO, 1998-1999). Full Professor of the Universidade de São Paulo (since 2005). Deputy-Dean (2001-2005) and Dean (2005-2009) of the School of Animal Sciences and Food Engineering (FZEA, Pirassununga campus), Universidade de São Paulo. Scholar Fellow at Princeton University (USA, 2002-2006). Academic Advisor of the Post-Graduation Provost of USP (2010-2014) and the first Head of the Biosystems Engineering Department at FZEA USP (2012-2014). Co-Editor in Chief of the Brazilian Journal Ambiente Construído (Antac, 2010-2016). He is the coordinator of the Research Nucleus for Biosystems Materials at USP since Sep/2012 . Member of the coordination committee at FAPESP in the Engineering area. More than 150 full papers published in peer reviewed journals. Member of the coordination team of the INCT Project - Advanced eco-efficient technologies for cement-based materials (aeCEM, since Dec/2016). Brazilian Responsible for the international thematic project in collaboration with the Université des Antilles (France). Responsible for research projects in collaboration with industries in the development of innovative construction components based on fiber-cement. Holmer has experience in Materials and Components for Construction, working on the following subjects: vegetable fiber, animal welfare, rural construction, civil construction and sustainability.
Vegetable fibers in the macro, micro and nanometric scales have been studied as reinforcement in cementitious materials. In nanoscale, the nanofibrillated cellulose has the advantage of having good mechanical performance and high specific surface, which contributes to improve the adhesion with the cementititous matrix. In hybrid reinforcement, with micro and nanofibers, nanofibrillated cellulose forms bonding with the matrix and acts as stress transfer bridges in the nano-cracking with corresponding strengthening of the cementitious composite even before the crack formation. Referring to the production processing, slurry dewatering followed by pressing has the advantage of favoring the dispersion of a higher amount of microfibers in homogeneous distribution (2D). The extrusion process strongly depends on the rheological characteristics of the fresh cement material but it can better organize the microstructure of the fiber cement due to the partial orientation of the fibers in the extruder direction. Curing process plays a key role in the performance of the final product and can contribute to mitigate the problem with durability of the materials and the corresponding effects on the mechanical performance of the composites. Degradation tests are crucial for the evaluation of the durability of the resulting materials and components in real applications exposed to different environmental conditions as roofing, partitioning or ceiling elements. The mechanical, physical, thermal and microstructure results both in the short and in the long term, demonstrate that lignocellulose fibers are suitable for more sustainable and high performance components for civil construction with adequate behavior for housing and infrastructure.