Isostatica

IC-NOCMAT 2007 - Maceió
International Conference on Non-Conventional Materials and Technologies:
Ecological Materials and technologies for Sustainable Constructions
Maceio, Alagoas , 13h-17th October 2007

PROSPECTIVE STUDY ON VEGETABLE WASTES AS REINFORCEMENT IN EXTRUDED FIBRE-CEMENT

Y.J. M. SOTO1; G.H.D. TONOLI2; R.S. TEIXEIRA3, S.F. SANTOS3; H. SAVASTANO JR. 3

1Escola Politécnica,Universidade de São Paul, Brazil.
2Escola de Engenharia de São Carlos, Universidade de São Paulo, Brazil.
3Faculdade de Zootecnia e Engenharia de Alimentos, Universidade de São Paulo - Avenida Duque de Caxias Norte, 225, 13635-900 – Pirassununga, SP, Brazil. E-mail: holmersj@usp.br

ABSTRACT

The extrusion process involves the formation of cohesive fibre-cement composites by forcing itthrough a die that can be adjusted to the various shape configurations. These sections are then cut to the desired length. This method can produce composites with high-density matrix and fibre packing, low porosity, and strengthening of the fibre matrix bond. This process also permits the use of residual fibres from the agro industry as raw materials for the production of cost-effective constructionelements.
In the present work four different types of waste fibres under 4 mm length were used as reinforcement with concentration of 1% by weight. The fibres were originated from the following different vegetable plants: coir, sisal, banana, and sugar cane. Tailoring of the composites were performed in an auger extruder using ordinary Portland cement, high range water reducer (HRWR), rheologicalmodifier and water soluble lubricant. The mechanical performance of the composites was evaluated by four-point bending test at 28 days of cure. Physical characterization by Archimedes procedure involved the determination of bulk density, apparent porosity and water absorption at the same age. Air permeability evaluation was conducted and the extruded composites presented unimportant incidence ofinter-connected pores. This result indicates good performance under weathering because it permits to associate the resistance to the penetration of degradation agents with the structure properties (e.g. particle packing and permeable pores). The extruded composites reinforced with coir and banana fibres maintained their mechanical properties after 200 cycles of soak/dry accelerated aging test.KEYWORDS: Agro industry; residues; banana fibre; sisal fibre; coir fibre; sugar cane lignocellulose fibre; cellulose; fibre cement; extrusion process.

INTRODUCTION

Natural fibres as reinforcement of fragile matrices based on cementitious materials have induced great interest in developing countries based on their low cost, availability, economy of energy, and also as asbestos substitutesregarding environmental concerns [1]. According to Swamy [2], the use of composites in flat sheets, roofing tiles and pre-manufactured components, can represent significant contribution for the infrastructure of these countries.
The available technologies for asbestos-free fibre-cement are well accepted in the developed world. However, they require large investments that are many times impractical,considering the reality of the low income countries. The developing societies have to look for alternative raw materials. Appropriate fibres and binders, different of the traditional raw material, frequently involve higher costs and great consumption of energy in their processing [3]. Another concern is the durability of the alternative products, as well as their compatibility to the usefulness ofthe life of the components that are destined to build the homes of the low income population [4].
Tropical countries like Brazil are indeed the domain of natural fibres mainly directed to cordage, textile and papermaking production. The heterogeneity and perishing of such fibres and also the market of restricted uses lead to the intense generation of residues with a high potential of pollution....