Title: Jointless Steel Fiber-Reinforced Concrete Slabs-on-Grade and on Piles
Author(s): E. Alexandre and B. Bouhon
Publication: Symposium Paper
Appears on pages(s): 89-102
Keywords: ductility; jointless slab; shrinkage; slab-on-grade; slab-on-piles; steel fiber-reinforced concrete; toughness; yield line.
Most maintenance problems associated with industrial concrete floors result from the joints. This paper emphasizes a method to eliminate saw-cut joints in slabs-on-grade by the use of steel fiber reinforced concrete (SFRC) only. The performance of the composite material is directly linked with the choice of a specific concrete mix design and an improved technique to uniformly mix a high dosage of steel fibers. Tests and experience have shown that high level post-cracking ductility of the SFRC can control micro-cracking caused by flexural and shear stresses combined with restrained shrinkage. The proposed design approach, based on the yield-line theory, gives an objective view of the safety factor in relation to the ultimate state. Case studies demonstrate that typical areas of 25,000 ft² (2322 m²), without saw-cut joints, are regularly achieved by experienced contractors with relevant site quality control. Practical site aspects such as armored contraction joints, slab details, aspect ratio, installation techniques etc., are an integral part of the case study as well. The second part of this paper details the use of this technique for structural applications such as suspended slabs on piles and mat foundations. To demonstrate the structural capacity of concrete solely reinforced with a high dosage of steel fibers, real scale tests and practical case studies are presented.