DPWH adopts new standards for pavement thickness

In a bid to ensure the quality of its road networks, the Department of Public Works and Highways has adopted new standards for national roads pavement thickness. DPWH Secretary Rogelio Singson said such standards should prevent the early deterioration of road pavements due to overloading. "In his Department Order no. 22, series of 2011, Singson directed that the thickness for the new construction and rehabilitation or upgrading of Portland Cement Concrete Pavements shall be 280 mm. However, a thickness of less than 280 mm, but in no case less than 230 mm may be adopted depending on the Cumulative Equivalent Single Axle Load (CESAL)," the DPWH said in a news release on its website. CESAL is the primary criterion used for the selection of the appropriate design of roads depending on the daily average effect of each vehicle type passing over the pavement. For pavement rehabilitation works using the crack and seat method, a minimum thickness of 260 mm is prescribed for the new pavement that will be constructed on top of the deteriorated pavement. But for pavement re-blocking, the thickness of the new pavement will be the same as the replaced blocks. In asphalt pavement, a minimum thickness of 50 mm is prescribed for overlaying works "but on grounds of economy, pavement thickness of more that 50 mm will be considered only if the cost of the asphalt pavement of such thickness is less than the cost of a 230 mm thick concrete pavement." "On both pavement types, the thickness of pavement will be verified from pavement design analysis using the American Association of State Highway and Transportation Officials (AASHTO) method as contained on the DPWH Design Guidelines," the DPWH said. AASHTO is a standards setting body which publishes specifications, test protocols and guidelines which are used in highway design and construction throughout the United States. The DPWH noted the Philippines, through the DPWH, is the only country outside North America authorized to use the AASHTO Standards. For pavement width, minimum width of the carriageway shall be 6.70 meters, while for rehabilitation or upgrading works involving at least 500 meters, the minimum width of the carriageway to be adopted shall be 6.70 meters. — LBG, GMA News