|SF sinkhole: gonna need a bigger patch (NBC Bay Area)|
any repairs that do happen are usually a lash-up [blogger's note: British - a makeshift, improvised structure or arrangement]. To save money, the material used for the patch is frequently “worked cold”. This means it is not heated with specialist equipment to make the bitumen in it soft enough to flow into the shape required and meld properly with the edges of the pothole. Instead the stuff is simply shovelled off the back of a lorry and pounded down.Microwaved patches, preventive-maintenance robots, and nanoparticle surfaces that "require no more than driving over them once a year with a special vehicle which generates an appropriate magnetic field" demonstrate that engineering minds remain keenly occupied in solving an important but un-sexy problem.
[Univ of Minnesota professor Larry] Zanko and his colleagues built an experimental repair vehicle equipped with a microwave generator on the end of a hydraulic arm. Using this on asphalt that contained between 1% and 2% magnetite, he found he could heat the material in a patch to 100°C in about ten minutes. At that temperature it could be tamped down to produce a more effective repair.
[Leeds professor Phil Purnell's] system would then activate a robotic repair vehicle when it came across a crack that needed fixing. This robot would come to the crack and fill it with a fast-setting bonding material (asphalt would not be needed, since no hole would yet have formed).
Thank goodness for engineers; while we talk, they do.