Applicazione di SRG per il rinforzo strutturale di travi in C.A.

The paper deals with the application of composite materials named Steel Reinforced Grout (SRG) for strengthening reinforced concrete (RC) elements. They differ from the well-known Fiber Reinforced Polymer (FRP) for the use of small unidirectional steel cords, combined to create a metallic fabric drowned in a matrix of cement mortar. In particular, this work develops an experimental program composed by two consequential phases. The first phase is aimed to find cement mortar matrixes with the best bond properties through pull-off tests in the case of cementitious substrate. The second part deals with flexural tests on RC beams strengthened with two SRG composites. On the basis of pull-off results two inorganic matrixes were selected according to their bonding and impregnation properties. The two SRGs were applied at the bottom of RC beams which were preliminary repaired with polymer-modified mortars in order to simulate a real on-site application of a strengthening layer on degraded RC elements. Flexural test results underline the high potentiality of the SRG strengthening technique also in the case of a double interface, concrete/ repair layer and repair layer/SRG. This technique needs a low level of specialization of workers and it is less expensive than FRP.