Durability of slag mortar reinforced with coconut fibre

Published Date

doi:10.1016/j.cemconcomp.2004.09.007

Natural fibre reinforced cement composites

Author

V.M. John ^a,b,,

M.A. Cincotto ^a

C. Sjöström ^b

V. Agopyan ^a

C.T.A. Oliveira ^c

• aDepartment of Construction Engineering, Polytechnic School, University of São Paulo, 05508 900 São Paulo-SP, Brazil
• bCentre for Built Environment, University of Gävle, 801 76 Gävle, Sweden
• cFaculty of Architecture, University of São Paulo, 05508 900 São Paulo, Brazil

Available online 24 November 2004.

Abstract

A comparative study of the microstructure of both new and in-use aged blast-furnace slag cement coir reinforced composite was performed. Aged samples came from internal and external walls of a 12-year-old house, built in São Paulo. The panels of the house were produced using 1:1.5:0.504 (binder: sand: water, by mass) mortar reinforced with 2% of coir fibre by volume. The binder was blast-furnace slag activated by 2% of lime and 10% of gypsum.

Fibres were removed from the composite and subsequently cleaned with acid solution (chloridric acid, 10%) in an ultrasonic bath. Both aged and new fibres were studied under low pressure BSE SEM with EDS analysis. The lignin content of the fibre was measured by the acetyl bromide method and qualitatively evaluated by Weisner reaction using an optical microscope.

Cement transformations were studied by X-ray diffraction and TG. Its pore water composition was also determined. Carbonation was measured by phenolphthalein. Composites were studied under low vacuum SEM. Interfaces and deposition of inorganic species in the fibre lumen were also investigated. Methods are described.

After 12 years, the cement was fully carbonated. Fibres removed from the old samples seem to be undamaged when examined under SEM. Qualitative lignin content determination by Wiesner reaction suggests that old samples have lower content of guaiacyl lignin units. Nevertheless, the total lignin content of old fibres when measured by using the acetyl bromide method, is comparable to that reported in literature. No significant difference was found in the lignin content of fibres removed from external and those removed from internal walls.

Keywords

• Cement composites
• Vegetable fibres
• Blast-furnace slag
• Durability
• Lignin
• Coir fibres

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• ⁎ 
  Corresponding author. Address: Department of Construction Engineering, Polytechnic School, University of São Paulo, 05508 900 São Paulo-SP, Brazil. Fax: +55 11 38185544

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Process for production of high density/high performance binderless boards from whole coconut husk Part 2: Coconut husk morphology, composition and properties

Published Date
September 2006, Vol.24(2):96–104, doi:10.1016/j.indcrop.2005.03.003

Author 

Jan E.G. van Dam ^a,,

Martien J.A. van den Oever ^a

Edwin R.P. Keijsers ^a

Jacintha C. van der Putten ^a

Cristina Anayron ^b

Fidel Josol ^c

Aurora Peralta ^c

• aAgrotechnology and Food Innovations, Wageningen UR, PO Box 17, 6700 AA Wageningen, The Netherlands
• bPhilippine Coconut Authority (PCA) R&D Building, 5th Floor, Elliptical Road, Diliman, Quezon City, 1100 Metro Manila, Philippines
• cFiber Processing and Utilisation Laboratory, Fiber Industrial Development Authority (FIDA), Bai Compound, Visayas Avenue, Diliman, Quezon City, Manila, Philippines

Received 12 July 2004. Accepted 11 March 2005. Available online 10 May 2005.

Abstract

For production of compression moulded boards from whole coconut husk the auto-adhesive properties are derived from the intrinsic high lignin content. Since the properties of manufactured boards for a large part will depend on the input husk material these properties are studied here. Husks of different varieties and maturity have been investigated for their contents of fibre and pith. Relevant physical properties and chemical composition were determined. For accurate determination of tensile strength and stiffness of coir fibre, its density (ρ_coir = 1.2–1.3 g/cm³) and cross-sectional area were determined. Both thickness and longitudinal swelling of the fibre were measured to assess the effects of water absorption.

The constituent fibre and pith fractions of coconut husk have been chemically analysed for polysaccharide (cellulose, pectin and hemicellulose) and lignin contents. Detailed carbohydrate analysis of the fibre indicated a glucose (cellulose) content of approximately 33% in the cell wall, together with 12% xylose as the major component of the hemicellulose fraction. Coir pith only contains 16% glucose. The effects of maturing on the chemical composition of the husk is analysed and a significant increase in glucose (cellulose) is observed, while for other sugars no dramatic change in relative amounts can be measured.

It was concluded that only slight differences can be observed between mature coconut husks of different origin, and all are suitable as input feedstock for boards production. More effects can be expected from the age of the nuts.

Keywords

Coconut husk

Coir fibre

Pith

Morphology

Chemical composition

Mechanical properties

Physical properties

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• ⁎ 
  Corresponding author. Fax: +31 317 475347.
  
  

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Mechanical performance of coir fiber/polyester composites

Published Date

doi:10.1016/j.polymertesting.2008.03.003

Author

S.N. Monteiro ^a

L.A.H. Terrones ^a

J.R.M. D’Almeida ^b,,

• aScience and Technology Center, Universidade Estadual do Norte Fluminense, Av. Alberto Lamego, 2000-Horto-28015-820, Campos, RJ, Brazil
• bMaterials Science and Metallurgy Department, Pontifícia Universidade Católica do Rio de Janeiro, Rua Marquês de São Vicente,225-Gávea-22453-900, Rio de Janeiro, RJ, Brazil

Received 24 January 2008. Accepted 10 March 2008. Available online 19 March 2008.

Abstract

The structural characteristics and mechanical properties of coir fiber/polyester composites were evaluated. The coir fibers were obtained from disregarded coconut shells that if not properly processed constitute an environmental hazard. The as-received coir fiber was characterized by scanning electron microscopy coupled with X-ray dispersion analysis. Composites prepared with two molding pressures and with amounts of coir fiber up to 80 wt% were fabricated. Up to 50 wt% of fiber, rigid composites were obtained. For amounts of fiber higher than this figure, the composites performed like more flexible agglomerates. The results obtained for flexural strength allowed comparison of the technical performance of the composites with other conventional materials.

Keywords

Coir fiber

Composites

Flexural strength

Micromechanics

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• ⁎ 
  Corresponding author. Tel.: +55 21 3527 1789; fax: +55 21 3527 1236.

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