Application of fiber reinforced high performance composites in spun-cast elements

Spin casting is an effective method to produce concrete pylons, masts or pipes. Through the centrifugation process the concrete is compacted and the desired shape, mostly round or ellipsoidal, is obtained. The pre-cast elements made using conventional concrete generally have to be reinforced with steel bars which are susceptible to corrosion. Furthermore, the placement of the steel reinforcement is time consuming and hence expensive and leads to rather thick and heavy structural elements. The application of short fiber reinforced cement (FRC) or mortar, as presented in this paper, is a suitable alternative for such weak-loaded bending elements. Special requirements regarding workability and strength have to be considered. Optimization of cement matrix was achieved with a blend of microfine cement and ordinary Portland cement, improving the theological properties of the fresh mixture and resulting in a very dense cement matrix with excellent mechanical properties. Reinforcement with different kinds of short fibers of carbon and polyvinylalcohol was studied. Flow properties of the FRC were optimized with regard to the centrifugation process applying a new cone-consistency test. The mechanical properties of conventionally cast specimens and of centrifuged prototypes were investigated. 1359-5997 (c) 2005 RILEM. All rights reserved.