Túlio Hallak Panzera

Statistical design of polymeric composites reinforced with banana fibres and silica microparticles

The study describes a design of experiment analysis performed on hybrid polymeric composites reinforced with unidirectional banana fibres and silica microparticles. Maleic anhydride was also evaluated as a chemical additive to improve the adhesion between phases. A full factorial design (2231) and the analyses of variance were performed to identify the significance of the microstructure constituents against different mechanical and physical properties in a total population of 120 biocomposites samples. The microstructure parameters considered were fibre volume fraction (30% and 50%), silica addition (0%, 20u2009wt% and 33u2009wt%) and maleic anhydride addition (0% and 2u2009wt%). The mechanical and physical properties of the composite considered as factorial and analyses of variance responses were the apparent density, apparent porosity, water absorption, modulus of elasticity and mechanical strength under tensile and flexural loading. The design of experiment analysis has shown that the volume fraction of the fibres significantly affects all responses, with the composite made from 30% of banana fibres exhibiting superior mechanical strength and modulus of elasticity. While the addition of silica has featured a statistically noticeable contribution to the porosity and the water absorption, the presence of the particles did not provide any significant enhancement to the composites mechanical strength. Maleic anhydride showed a significant contribution to the apparent density, water absorption and flexural modulus, not improving the adhesion between phases, with a consequent decrease of the Young’s modulus and increase of the water absorption within the composites.

15 – High performance fibre-reinforced concrete (FRC) for civil engineering applications

Abstract: Portland cement concrete is a brittle material. The main reason for incorporating fibres into a cement matrix is to improve the cracking deformation characteristics, increasing not only the toughness, impact and tensile strength, but also eliminating temperature and shrinkage cracks. Several different types of fibres have been used to reinforce cement-based materials. This chapter briefly discusses the characteristics of fibre-reinforced concrete (FRC), reporting the effect of the fibres on the physico-chemical and mechanical properties. It also presents some of the recent research and future perspectives of FRC.

Replacement of Quartz in Cementitious Composites Using PET Particles: A Statistical Analysis of the Physical and Mechanical Properties

AbstractThis work investigates the mechanical behavior of cementitious composites (mortar) when quartz inclusions are totally or partially replaced with polyethylene terephthalate (PET) particles. A full factorial design is performed to identify the effect of the water/cement ratio and the range of quartz particles size used in the replacement on the different mechanical and physical parameters (bulk density, apparent porosity, water absorption, oxygen permeability, compressive strength, and modulus of elasticity). The results show a general reduction of the mechanical properties when the replacement with quartz particles is put in place. The composites made by replacing the coarse quartz particles showed acceptable mechanical properties for nonstructural civil engineering applications, with a significant amount of PET recycling to be used as aggregates for some specific end-user cases.