ABSTRACT
Concrete has been widely used in the construction of roads, highways, industrial floors and pavements since early twentieth century. Construction methods generally include placement of joints at specific distances to control the cracking phenomenon. The latter is due to the development of tensile strains caused by the shrinkage of concrete and by environmental factors, such as temperature gradient. However, joints result in reduced load carrying capacity, local failure, and pavement damage. To reduce the number of joints, the fracture toughness of concrete can be enhanced by adding fibers. As the models available for conventional fiber-reinforced concrete (FRC) cannot be extended to high-performance fiber-reinforced concrete (HPFRC), the aim of this work is to describe a new model to design HPFRC joint free slabs. Specifically, a composite cross section made of soil and concrete, which is subjected to imposed strains, is modelled through the Colonnetti's theory of elastic coactions. In this way, not only the effect produced by concrete shrinkage but also the nonlinear response of HPFRC in the strain hardening stage are taken into account. For given maturity curves, crack does not appear if the maximum tensile strain provided by the model is lower than the strain that produces localization in HPFRC.
