Investigation on road damage due to vehicle overloading of high volume Ipoh state road

Traffic load was a major factor in thickness design due to the main function of pavement which was to resist traffic load. Although efforts to repair the road damage had been done continuously, the recovering effects were almost meaningless if the road was continuously receiving overloading from vehicles. Issues of road damage due to vehicle overloading had been addressed by most agencies in developing countries. However, there were no available study to address this issue on Perak state road. Therefore, this research aimed to determine the current traffic composition, the percentage of overloading vehicle, the Equivalence Factor (E.F.), the adequacy of existing pavement thickness and the reduction of pavement service life due to overloading of the road by referred to AASHTO and Arahan Teknik (Jalan) 5/85. The selected study area was at Jalan Tuanku Abdul Rahman, Ipoh (also known as Jalan Kuala Kangsar). Data were employed which acquired from traffic count survey, axle load survey, coring test and dynamic cone penetrometer test. Review on current traffic count data showed that vehicles with 2-axle contributes more than 60% of the overall daily traffic while percentage of overloading vehicle revealed that more than 50% of vehicles contributed from 4-axle, 5-axle and 6-axle exceeded the maximum permissible gross vehicle weight (PGVW). The analysis on the E.F. showed that primary and secondary directions gained E.F. value of 4 and 3 times higher than the 3.0 E.F. design value which were 12.4 and 9.2 respectively. This also denoted that additional overlay pavement thickness was required about 70mm and 50mm for primary and secondary direction respectively to ensure the target design life was achieved. This study also discovered the road pavement experienced 7 and 6 years of reduction of service life for both directions respectively.