Development of spring load restrictions using Canadian long term pavement performance data

In northern parts of North America, the road network can be weakened and damaged by seasonal loading. The yearly cycle of above and below freezing temperatures causes cycles of freezing and thawing of the groundwater underneath the pavement. During spring, the frozen ground thaws from the surface down and causes the water to become trapped between the pavement surface and the frozen soil, thereby saturating the soil. The pavement is in a weakened state during this saturated period, which can last up to several weeks every year. Most authorities have opted to impose load restrictions on vehicles during this thawing period. Yet, it is difficult to determine the exact time period that the pavement is in this weakened state. This paper will investigate ways to improve the determination of the duration of load restrictions with LTPP data, and the possibility of adopting it for use in Ontario.