Timber-concrete composite system represents a diffused solution for floor elements both in new structures as well as for the refurbishment of ancient ones. These two members are linked by a connection elements that, in this case, are inclined lag screws. This study has the aim to investigate the behaviour of a typical timber-to-concrete composite slab by performing FE simulations. Some previous results coming from push-out tests will be accounted in order to calibrate the numerical model, after this, different screws geometrical features (i.e. inclination) will be defined in order to establish their influence on the specimens' global behaviour. Then, starting from the previously defined screws configurations, the concrete is replaced with Rubbercrete, which is a concrete in which part of the natural aggregates are replaced with recycled waste tyre rubber. The effect of this substitution will be investigated and highlighted.
