This technology is a concrete composition featuring a shape memory alloy (SMA) anchoring system. Rod-shaped SMA reinforcement is placed inside the concrete, and both ends are secured outside the concrete surface using an anchoring device consisting of a base plate, a support cylinder, and stoppers. It operates on a wedge principle where the friction against the stoppers increases as the ends of the reinforcement are pulled into the concrete.
Concrete reinforced with SMA has the advantage of a gradual load drop after yielding and the ability to close cracks due to the superelastic effect. However, because SMA cannot be processed with ribs like deformed steel bars, its bond strength with concrete is low. This often leads to slippage as the load increases, and even after the load is removed, the concrete on both sides of the crack remains separated, compromising structural safety.
This technology features multiple stoppers placed inside a support cylinder that narrows toward the bottom, wrapping around the outer surface of the reinforcement. Side protrusions on the stoppers fit into guide grooves on the inner wall of the cylinder, allowing only vertical movement without rotation, while a stopper at the top of the guide groove prevents the stoppers from detaching. The end of the reinforcement has friction grooves, the base plate includes a grouting groove for adhesive and a coupling groove for the support cylinder, and the tightening strength can be adjusted via the gap between two semi-circular cylindrical members. Applicable to bridge columns and beams requiring seismic reinforcement, public facilities needing post-earthquake self-healing, and SMA tension members for prestressing, this system prevents reinforcement slippage, allowing the SMA to return to its original shape after an earthquake and effectively close cracks.
This invention was developed with support from the Ministry of Land, Infrastructure and Transport for the development of carbon-polymer corrosion-zero reinforcement alternatives.
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