• Dannau, Michel
• Vanherck, Jan
• Wastiels, Jan

Abstract

The use of a cementitious matrix may be an interesting choice for composites with an improved fire resistance: their low temperature processing like polymers, in combination with good thermal stability of ceramics, could lead to the best of both worlds. The very low strain at which cementitious materials develop cracks while under tension implies that when substantial post-cracking stiffness and strength of the composite is expected, stiff and strong fibres should be used in a continuous reinforcement structure, using composite production techniques. Economical arguments lead to glass fibres, which are however lacking durability in an alkaline cement environment. The non alkaline chemically bonded ceramic material vubonite, developed at Vrije Universiteit Brussel, avoids these drawbacks, and is fully compatible with glass fibre reinforcement. <br/>The very low cracking strain in tension calls for an accurate modelling of the post-cracking behaviour of textile reinforced cement composites, where frictional interaction between fibres and matrix determines the properties. Simple models as the ACK-theory are shortly presented, as well as predictions of the more sophisticated stochastic cracking model. This highlights that the high volume contents of fibres, which can be obtained only with textile reinforcement structures, are necessary to obtain the desired high strength and post-cracking stiffness under tension, as well as strict crack opening control. These characteristics are necessary for load-bearing sandwich panels with cement or vubonite composite faces.

Topics

• impedance spectroscopy
• polymer
• theory
• glass
• glass
• crack
• strength
• composite
• cement
• ceramic
• durability