Concrete compressive strength estimation in-situ at precast beams using direct and indirect testing methods according to EN 13791

Concrete precast bridges are increasing worldwide because of their clearly advantages compared to other structural systems. It is widely known that estimation of concrete compressive strength has a crucial meaning for safety, durability, serviceability and long-life of a structure. Also, the compression test of cubic specimens is a classic and reliable test application but does not take account all the parameters that influence the concrete strength that is developed in structure in-situ. Therefore, for a precast bridge which is constructed from different structure elements, it is important to estimate compressive strength in-situ taking into account the effects of both the material and execution (compaction, curing, etc.) using direct and indirect testing methods. In the present paper, the compressive in-situ strength of concrete precast beams was carried out accordingly to EN 13791:2007 where direct (cored specimens taken in-situ in uniaxial compression) and indirect (Schmidt Rebound Hammer, Pull-out force) testing methods were executed at the mid-span of bridge beams. Finally, advantages and disadvantages that result by the application of indirect testing methods and EN 13791:2007 are presented.