Instant Road Repair 10mm Tub 25kg. £ 39.95 £ 37.95. 10mm grade Ultracrete Instant Road Repair (IRR) by Instarmac is a tarmac repair mpound as used on motorways! Fast, cheap and totally durable and ‘Best in class’. Use for a quality long-term temporary repair to mend potholes in paths, drives, driveways, roads, cycle tracks, car parks