Adjustments in the mixture formulations for the production of fiber cement by the extrusion process

• Grant number: 05/04035-7
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: November 01, 2006
• End date: October 31, 2009
• Field of knowledge: Engineering - Civil Engineering - Construction Industry
• Principal Investigator: Holmer Savastano Junior
• Grantee: Yatsen Jepthe Maldonado Soto
• Host Institution: Escola Politécnica (EP). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Extrusion represents an excellent substitution to the Hatschek process in the development of fiber-cement composites. The extrusion is considered a more efficient method in the following aspects: energy consumption in production, variety in the geometry of products and the lower cost of implementation per production line. Also, extruded composites of fiber-cement have a greater mechanical performance, and a better durability. For extrusion to be possible, a study of the formulation rheology becomes a factor of extreme importance. Within this context, the main reason for the non implementation of that process by the national industry can be attributed to the lack of an adequate study of the rheological aspects of the mixtures. The objective of this work consists on the adjustment of the extrusion of formulations based on the raw materials used by the industry of asbestos free fiber-cement. The work must be implemented in two stages. In the first one, statistical techniques will be used for the experimental planning and the optimization of the mixtures. In the second stage, packaging models will be adjusted to predict the behavior of the formulation in the fresh and hardened states. The statistical techniques will be used to find the extrudable formulations with a rheometer extruder. With the extrusion formulation, and the same statistical techniques, a formulation will be determined to produce a cement sheet, with the best physical, mechanical and durability characteristics. In the second stage of the work, for every group of the extrusion formulation, the following subsystems will be studied: the packaging of particles, the dispersion of the particles and the rheology of the liquid phase. The specific objective of this stage is to understand the influence that each subsystem has on the rheological behavior of the mixture, its physical and mechanical characteristics, and the durability of the hardened composite. (AU)

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

SOTO, Yatsen Jepthe Maldonado. Adjustments in the mixture formulations for the production of fiber cement by the extrusion process.. 2010. Doctoral Thesis - Universidade de São Paulo (USP). Escola Politécnica (EP/BC) São Paulo.