Autogenous Self‐healing of CTRC Repair Layers Exposed to Tensile Threshold Loading

The experimental investigations presented in this paper contribute to fill the knowledge gaps on the subject of autogenous self‐healing of DURTEX layers for the surface repair of cracked or cyclic crack opening of concrete and reinforced concrete structures. Composite specimens, so‐called crack distribution specimens, were subjected to at least 1000 and up to 6900 cycles. Investigations show that neither the crack characteristics (e. g. crack width, crack geometry) change nor the mechanical properties (e. g. adhesive tensile strength or tensile load‐bearing behavior) are reduced compared to the reference specimens as a result of cyclic loading with both pore and crack water pressure. Also, the self‐healing potential of a selected material combination is demonstrated despite cyclic loading. It was observed that cracked DURTEX layers with w_max = 0.116 mm, under cyclic loading (Δwop = 0.6 mm) at a constant test speed set to 0.05 mm/min (piston controlled) with a 5 m pore and crack water pressure can self‐heal themselves leading to water tightness after 14 days. Chemical‐mineralogical analysis using X‐ray diffraction (XRD) on material taken from the cracked surface of the specimen evidenced the formation of CaCO₃ as calcite.