Investigation on road damage due to vehicle overloading in Kuala Krai federal road

Abstract

Networks of paved roads is the dominant infrastructure in the domestic transportation system in Malaysia. Public roads are constantly put under pressure, quite literally, from all the traffic that utilizes them. The longevity of the pavement is highly dependent on two opposing factors; the design thickness of the pavement, and the traffic load, or in simpler words, thick pavements supporting less traffic load will have the maximum lifespan, to a certain extent. Road damage is not an uncommon problem for the authorities and although repairs are done regularly, the effort is practically meaningless if the road continuous receiving overloaded vehicles. This issue has been addressed by many agencies, even in developing countries. However, there is no available study that addresses this issue for Kuala Krai roads. Therefore, this research aims to investigate the effects of vehicle overloading on road damage on Kuala Krai federal roads. The selected study area is the FT008 Kota Bharu - Gua Musang Road, Kelantan. Traffic data was acquired from the Road Traffic Volume Malaysia (RTVM, 2019), traffic count survey, and axle load survey using the weigh-in-motion technology. Based on the available traffic data, the passable pavement layer thickness was calculated and compared to the existing pavement thickness, obtained by field density test, and the standard pavement thickness as set by the Public Works Department. The traffic volume and load survey revealed that commercial vehicles made up 42% of all traffic on the study location, and most of the vehicles that violated the permissible gross vehicle weight (PGVW) were of Classes 3 and 4, despite being infrequent. The calculation of required pavement thickness based on the Equivalence Factor (E.F.) of the surveyed traffic indicated that the existing pavement thickness was highly inadequate for the current traffic load. The pavement thickness was also unsatisfactory based on the standard design requirements by the Public Works Department. Based on the calculation of service life reduction, the pavement service life is expected to be 6 to 7 years shorter than the intended design. In conclusion, the overloading of heavy vehicles and the inadequate pavement thickness has caused major depreciation to the pavement safety and quality, reducing its service life and requiring more rehabilitation works.