ABSTRACT

Characterization of the crack pattern created during multiple cracking of the matrix is the information required to apply SH mechanisms on cementitious composites efficiently.

2.2 Advanced optical technique as a tool to visualize crack patterns on two different TRC series

The ability to “see” and become aware of the crack opening and propagation of the two skin reinforcing systems is critical in our effort to choose the optimized self-healed TRC. On this direction, the crack propagation is investigated by the use of Digital Image Correlation (DIC), an advanced and well established optical Non Destructive Technique (NDT). Literature review of the geometry, the test set-up, the loading case and the material shows that Inorganic Phosphate Cement (IPC) and fine grained concrete (FGC) elements reinforced by fiber textile and tested under tension give a first and representative view of the cracking phenomenon appeared on TRC composites. Both cementitious matrices, combined with glass fibre reinforcement, produce strong, durable and thin

1 INTRODUCTION

1.1 Investigating limited crack width

Studies have shown that self healing (SH) in concrete is managed only in regions of damage with tight crack width, likely less than 100-150 μm, which is very difficult to achieve in a consistent manner for concrete in the field. In our work, the feasibility of yet another solution to the problem is investigated namely the use of glass fibre reinforced cementitious composite skins as self healing systems which are able to limit the crack width to less than 50 μm (ideal for the healing efficiency). This paper is focusing at the estimation and visualization of the crack pattern at the most critical stage under tensile loading of fibre textile reinforced cementitious composites (TRC), results from two different TRC systems will be compared and the most appropriate would be chosen for further application of SH mechanisms.