Stating that faulty road compaction is one of the primary reasons for potholes, the Chennai Corporation has stated that it has set up quality control laboratories in each of its 15 zones to improve the quality of its road construction works.    The Corporation stated that a density of 2,230 kg/m for roads will help the stretch last longer. The equipment in the laboratory includes facility for core cutting, sieve analysis digital thermometer, one-milligram accuracy weighing machine, identification of pavement quality and camber of roads.    Camber means a slight slope curve from the centre of a road or other surface to the side, which makes water flow to the side drains.    To improve quality control of roads in the Chennai more equipment will be procured, said the Corporation. The civic body will keep an eye on quality of road re-laying in each of the 15 zones with such facilities in place.