Steel fibre reinforced light weight aggregate concrete for strengthening and repair

Abstract

Light weight aggregate concrete (LWAC) is an upcoming building material which is characterized by many favourable hardened concrete properties. However, like all concretes. LWAC shows the disadvantages of a quite low tensile strength and a large brittleness. To immprove the tensile strength, the ductility and the toughness it is useful to reinforce the LWAC with steel, glass or synthetic fibres. Currently, steel fibres, which are often favoured in practice, areavailable in a high variety concerning their strength, geometry, shape and surface properties. The first part of the paper describes a test programme that was focused on the determination of the most suitable steel fibre type regarding the demanded fresh and hardened LWACproperties. Within the experimental investigations a large number of single steel fibre pull-out tests and 4-point bending tests were performed. The main result is the possibility to give a statement to tl efficiency of the various tested fibre types. Steel fibre reinforced light weight aggregate concrete is especially suitable for the strengthening and the repair of existing structures, because this material combines a relatively high strength with a low density. Particularly, the load-bearing capacity of timber beam floors and of concrete slabs can be increased by the addition of a steel fibre reinforced light weight aggregate concrete layer. The second part of the paper reports practical applications of this innovative building material for strengthening and repair. Finally, differences in Germany and Lithuania are indicated with regard to the varying economical boundary conditions for the revaluation of existing structures in both countries.