9Durability of Hybrid Polypropylene-Glass Fibre.pdf

ELSEVIER PII:SO958-9465(97)00075-9 Cement and Concrete Composites 20 (1998) 19-84 0 1998 Elsevier Science Ltd. All rights resewed Printed in Great Britain 0958-9465/98/$19.00 G. XQ* S. Magnani” D. J. Hannantb “Fibronit S.R.L. Broni (PV), Italy ‘Department of Civil Engineering, University of Surrey, Guildford, Surrey, UK (Received 21 August 1997; accepted 12 December 1997) Durability of Hybrid Polypropylene-Glass Fibre Cement Corrugated Sheets Abstract Two types of fibre cement corrugated roofing sheets, one being a hybrid containing fibrillated polypropylene networks and alkali resistant glass fibres, and the other reinforced solely by the fibril- lated polypropylene networks, have been exposed to natural weather for six and ten years, respec- tively. Flexural test results indicate that, for these Rxposure periods, the strength and toughness for both types of sheets has been little ajfected. A 20% increase in flexural peak load was found for the hybrid polypropylene-glass jibre cement sheets. 0 1998 Elsevier Science Ltd. All rights reserved. Keywords: Fibrillated polypropylene networks; glass fibres; hybrid sheets; PP sheets; natural weathering; load-deflection curves; durability INTRODUCTION The concept of utilising layers of fibrillated polypropylene film, opened up to form net- works, to fabricate fibre cement thin sheeting was developed by the University of Surrey in the late 1970~‘*~. The use of networks of fibril- lated polypropylene film can yield a composite with high energy absorbing capacity, compared with other fibre cement sheet materials avail- able in the market. *Correspondence to G. Xu at: Institute for Research in Construction, Canadian National Research Council, Ontario KlA OR Canada. In order to manufacture the material in large volumes, an industrial process, the Reticemf process, in which fibrillated polypropylene net- works are fabricated into a semi-dry cement matrix with subsequent vacuum dewateri