ABSTRACT
Precast tunnel linings have been in use for many years in tunnel construction. The use of conventional rebar for tunnel segments, has however one major handicap in its limited durability. In aggressive environments mainly corrosion problems with conventional rebar have and are being reported. The main function of the top and bottom mats is to resist the bending forces related to demoulding, stacking, transportation and ground conditions. The edges of the cages, consisting of stirrups and longitudinal bars parallel to the segment border, resist the jacking forces of the tunnel boring machine. The spalling problems encountered using conventional reinforcement can be avoided by the use of steel wire fibres. Compared to conventional reinforcement, steel wire fibres provide a better resistance against spalling due to the homogeneous distribution of the fibres and their excellent durability. The use of steel wire fibres minimizes damage to segments during handling, transportation, ring building or pushing and thus reduces repair costs.
