Composite materials for new construction systems: experimental and numerical investigations.

The present thesis intended to contribute for the development of a new generation of high durable and sustainable reinforced concrete (RC) beam structures submitted to flexural loading, by combining the benefits that Glass Fiber Reinforced Polymers (GFRP). The main benefit given by the GFRP bars is their corrosion immunity. Furthermore, the Fiber Reinforced Concrete (FRC) was developed to improve the ductility of structures and to provide greater shear strength. One of the advantages of not being attacked by chemicals, is to have the possibility of using a very reduced concrete cover for greater structural functionality. Although, conventional shear reinforcements were not used, they were totally replaced by FRC material and a new 3D positioning geometry of the GFRP bars allowed to help this resistance, even if it is not considered in the design calculations. Due to the quite high post-cracking tensile strength and energy absorption capacity that this composite material attained, the system showed adequate bending resisting, and enhancement in the structural performance at serviceability. The work started with the assessment to behaviour of GFRP and FRC through experimental tests and analytical investigation. The structural performance of this GFRP reinforced FRC was investigated by performing four-point bending tests on beams. Moreover, an extensive analytical formulation was developed in order to theoretically address to the main structural aspect of the tested beams. The obtained experimental results were captured well using the respective results from the analytical study. Finally, finite element simulations were carried out, using well-known modelling approach available in the literature for elements in form of 3D models.