Paper by BÄUML HARDEGGER from ISCR 10th 2006 Brussels Belgium
Repair of concrete airstrips is a matter of particular interest. Besides being costly, it obstructs airport operations. Consequently, materials and construction procedures must comply with technical and operational demands. This article describes the development and application of a cementitious rapid hardening binder and a corresponding polymer fiber concrete for the repair of airport runways. The resulting concrete can be produced, transported and cast by means of usual equipment and procedures. It features the following main properties: Pot life of about 60 minutes even at high temperatures. 20 MPa of compressive strength reached within 60 min. after initial setting even at low temperatures. Prevention of cracking due to low shrinkage and by means of polymer fiber reinforcement. As a case study, the application of this concrete at Zurich airport is described: Runways at Zurich airport are mainly non-reinforced concrete slabs, subdivided into square elements with an edge length of about 7 m. Within the framework of ongoing repair and maintenance, single deteriorated elements can be replaced within a time frame of only 6.0 hours each night. Reliability of both concrete workability and early age strength under various conditions is a matter of particular interest to the general contractor, while concrete durability is of particular interest to the airport authority. Both demands have to be fulfilled.