Pultrusion technique

As gradient textile technologies already demonstrate, fibers should only be incorporated where they are useful in carrying loads. In less stressed parts of a construction, polymer foam will be used for spacing out fibers. With the braid-pultrusion technique, this principle can be applied very easily into the structure. 

Give a brief description of the pultrusion technique for the preparation of composite materials. 

The pultrusion technique is a closed mould system, and is a fully automated continuous process. Continuous fibrous reinforcement rovings and... 

Ben, G. and Shoji, A. (2005), Pultrusion techniques and evaluations of sandwich beam using phenohc foam composite , Ariva/iceri Composite Materials, 14, 277—288. 

The pultrusion technique, in which the factory-made rigid pre-cast FRP plate is bonded onto the degraded member on site with ambient cure adhesive polymer. The pultrusion method is described in Hollaway (2008) and Starr (2000). 

The FRP rebars are generally manufactured by the pultrusion technique from thermosetting resins such as continuous carbon, glass or aramid fibres embedded in polyester, vinylester or epoxy matrix (Nanni, 1997 ACI, 1996 Pilakoutas, 2000 Bank, 2006). Their geometric cross-sections are typically round, square or rectangular and have smooth surfaces these must be modified to improve the bond characteristics between the concrete and the rebar. The improvements in bond characteristics are effected by forming ... 

The reinforcements amenable to RTM are similar to those used for pultrusion, except that they need not be continuous in nature. Thus, E-glass, S-glass, aramid, and carbon fibers are commonly used, as are discontinuous filaments such as wood fiber and polyesters. Even metal and ceramic fibers can be used in this technique. In one method, the preform is fabricated by spraying 12- to 75-mm-long chopped fiber rovings onto a preshaped screen. A binder sprayed with the fibers keeps them in place and holds the preform shape, which is then placed in the mold. 

Joshi S. The pultrusion process in polymer matrix composites. In Advani S, Hsiao K-T, editors. Manufacturing techniques for polymer matrix composites (PMCs). Cambridge (UK) Woodhead Publishing Limited 2012. 

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