Temporary repair of concrete beams by embedded shape memory alloy actuators

The development of smart materials has paved the way to the creation of adaptive and self-healing structures. Shape memory alloys (SMA) embedded in a structure can provide crack closure and temporarily restore structural integrity. The active emergency repair should be followed by long term strengthening, which benefits from the reduced crack width. Here, small scale self-healing concrete beams are built and tested. Prestrained SMA wires are embedded in the beam, while fibre Bragg grating (FBG) sensors are used to detect a critical beam conditions and activate the emergency repair. The actuation of the shape memory alloy elements leads to a crack size reduction and to a decrease in the inelastic beam displacement. Further experimental investigation is necessary to determine the influence of beam ductility and other factors on the amount of repair provided by the SMA actuators.