High performance composites in spun-cast elements

Spin-casting is an effective fabrication method to produce concrete poles, masts or pipes. Through the centrifugal process the concrete is compacted and the desired shape, mostly round or ellipsoidal, is obtained. The concrete generally has to be reinforced with steel bars which are susceptible to corrosion. Furthermore, the placement of the reinforcement is time consuming and hence expensive and leads to rather thick and heavy structural elements. The application of short-fiber reinforced cement pastes or mortar is a suitable alternative.Special requirements regarding workability and strength have to be considered. An optimization of the cement matrix was achieved with a blend of microfine cement and ordinary Portland cement, improving the rheological properties of the fresh mixture and resulting in a dense cement matrix with excellent mechanical properties. Reinforcement with different kinds of short-fibers of carbon and polyvinylalcohol (PVA) was studied.Flow properties of the fiber reinforced cement composite were optimized with regard to the centrifugal process by applying a newly developed cone-consistency test. The mechanical properties of conventionally cast specimens and of centrifuged prototypes were determined and their durability was verified. Workable, high strength, ductile and durable fiber reinforced composites were obtained in spin-cast elements.