Fibre - Plastic Composites in Construction

The application of lignocellulosic fibres in reinforcing plastics has been known for a long time. As early as 1908 the first composite materials were applied for the production of large quantities of sheets, tubes and pipes for electronic purposes (paper or cotton to reinforce sheets, made of phenol or melamine formaldehyde resins). In 1896, aeroplane seats and fuel tanks were made of natural fibres with a small amount of polymeric binder [1], 

Because of low prices and the steadily rising performance of technical and standard plastics, the application of natural fibres for obtaining lignocellulosic fibre - plastic composites is widely used. More recently, the critical discussion about the preservation of natural resources and recycling has led to a renewed interest concerning natural materials with the focus on renewable raw materials [2], 

The field of natural fibre reinforced thermoplastic composite materials is now rapidly growing both in terms of industrial applications and fundamental research. 

Agro-based lignocellulosics suitable for composites come from two main sources. The first is agricultural residues and the second is those lignocellulosics grown specifically for their fibre. The first source includes rice husks or cereal straws, which are by-products of food or feed crops and can be used for everyday purposes such as animal bedding or fuel or alternatively are simply left on the field or burnt to reduce mass. Two examples of the second source are jute and kenaf. These plants also have residues, which are often used for bedding or fuel as well. 

Technically speaking, almost any agricultural fibre can be used to manufacture composite panels. However, it becomes more difficult to use certain kinds of fibres when restrictions in quality and economy are imposed. The literature shows that several kinds of fibres have existed in sufficient quantity, in the right place, at the right price and at the right time to merit at least occasional commercial use. 

---

The susceptibihty of resins, reinforcing fibres and composites to aqueous and non-aqueous environments has been reviewed. It is clear that with careful material selection and composite construction, reinforced plastics are very durable in aggressive conditions. One of the most severe environments, aqueous acids, can be designed to use the ideas presented here. This practice is implemented in industry, as demonstrated by the durability of GRP in environments encountered in chemical plant and conduit for corrosive effluents. 

Abbasi, A. and P. J. Hogg (2004). Fire testing of concrete beams with fibre reinforced plastic rebar. In Advanced Polymer Composites for Structural Applications in Construction, ed. L. C. Hollaway, Cambridge, UK, Woodhead Publishing, pp. 445-456. 

The wood fibres used in plastics are not often post-consumer material but they may be waste from sawmills. Over 330,000 tonnes of wood flour was used in resin-based composites in North America in 2003. The Emopean figure is only about 10% of the North American one but consumption can be expected to increase, with new applications in outdoor and indoor furniture, vehicles, decking, construction and infrastructure. European manufacturers of wood filled plastics include Fasalex, Tech-Wood, Haller Formholz, Knotwood, Timbaplus and Ecodek. 

Chapter 8 concentrates on sustainable construction. Wood-plastic composites are being used in construction at an increasing rate. Lignocellulosic fibres and plastic composites are extensively discussed in Chapter 10. 

And since most of the plastic composites used in construction are of fibre reinforced thermosets, these will be emphasised in discussions. 

Hill, P. S., Smith, S. and Barnes, F. J. (1999), Use of high modulus carbon fibres for reinforcement of cast iron compression struts within London Underground project details , Conference on Composites and Plastics in Construction, November 1999, BRE, Watford, UK. RAPRA Technology, Shawbury, Shrewsbury, UK, paper 16 1-6. 

---