An innovative self-healing, low-carbon structural repair mortar has been developed and used to repair a wall along the N13 highway in the Canton of Grisons (Switzerland) affected by alkali-silica-reaction (ASR). Meeting SN EN 1504-3 class R3 (structural repairs) standards, the mortar exhibits self-compacting behaviour in the fresh state, enhanced ductility, and acts as an impermeable barrier against the ingress of water into the wall affected by ASR. The mortar can be mixed by conventional site batching plants (with compulsory or non-compulsory mixers alike) and exhibits approximately 60% less embodied CO₂ emissions than the “off-the-shelf” alternatives. This is due to: the incorporation of locally sourced aggregates, low clinker cement, and a proprietary cementitious filler that promotes self-healing, enhances durability and, thus, reduces maintenance. The mortar’s tensile strain capacity, is twice that of conventional concrete, improving the compatibility with the substrate and minimizing cracking potential. The laboratory and in situ results have confirmed the mortar’s robustness, both in the fresh and hardened state. The mortar has been cast both by bucket and pump. The self-healing mortar is thus a versatile concept applicable to: various geographical contexts, different types of low clinker cements easily available in the European markets, different placing methods (pump, bucket, spraying), offering a sustainable and durable solution to the repair of concrete. Its low clinker content, combined with enhanced performances and durability, meets the goal of halving, as a minimum, the carbon footprint of concrete materials.