A new pavement design procedure for frost protection in seasonal frost areas

Resumo

Differential frost heave and uneven degradation of flexible pavements surface
profile in cold climate significantly affects the serviceability of these important civil
engineering structures. Among the factors influencing this phenomenon, subgrade soils
variability is documented as a significant parameter to consider, especially regarding
differential frost heave. Subgrade soils variability may increase in urban area because of the
buried utilities and the numerous cuts, both usually filled with granular materials. Therefore,
past researches were revisited to implement a design methodology for frost heave protection
of flexible pavements in northern environment based on the risk of differential frost heave
caused by subgrade soils variability. Previous data were used to 1. Propose a relationship
between the maximum pavement IRI, usually encountered at the end of the winter period, the
design period and the subgrade soils longitudinal variability index, and 2. Quantify the effect
of the replacement of in situ subgrade soils with granular fill on the coefficient of variation of
frost heave. The relationship was used as a reference to identify allowable average frost heave
based on subgrade soils variability conditions. This is specifically applicable in the urban
context for which granular fills, and consequently supplementary induced soil variability, is
the main factor contributing to the determination of the allowable frost heave. Working
examples of various classes of urban pavements allowed obtaining allowable frost heave
criteria that take into account subgrade soils variability, design period and maximum
allowable roughness, which are also in good agreement with available data in the literature.