**Viviane Adam \* , Jan Bielak , Christian Dommes, Norbert Will and Josef Hegger**

Institute of Structural Concrete, RWTH Aachen University, 52074 Aachen, Germany; jbielak@imb.rwth-aachen.de (J.B.); cdommes@imb.rwth-aachen.de (C.D.); nwill@imb.rwth-aachen.de (N.W.); jhegger@imb.rwth-aachen.de (J.H.)

**\*** Correspondence: vadam@imb.rwth-aachen.de

Received: 31 August 2020; Accepted: 16 September 2020; Published: 22 September 2020

**Abstract:** Many older bridges feature capacity deficiencies. This is mainly due to changes in code provisions which came along with stricter design rules and increasing traffic, leading to higher loads on the structure. To address capacity deficiencies of bridges, refined structural analyses with more detailed design approaches can be applied. If bridge assessment does not provide sufficient capacity, strengthening can be a pertinent solution to extend the bridge's service lifetime. For numerous cases, applying an extra layer of textile-reinforced concrete (TRC) can be a convenient method to achieve the required resistance. Here, carbon fibre-reinforced polymer reinforcement together with a high-performance mortar was used within the scope of developing a strengthening layer for bridge deck slabs, called SMART-DECK. Due to the high tensile strength of the carbon and its resistance to corrosion, a thin layer with high strength and low additional dead load can be realised. While the strengthening effect of TRC for slabs under flexural loading has already been investigated several times, the presented test programme also covered increase in shear capacity, which is the other crucial failure mode to be considered in design. A total of 14 large-scale tests on TRC-strengthened slab segments were tested under static and cyclic loading. The experimental study revealed high increases in capacity for both bending and shear failure.

**Keywords:** reinforced concrete; bridge deck slabs; strengthening; textile-reinforced concrete; carbon concrete; static loads; fatigue loads; experimental investigations
