Frost modelling and pavement temperatures : summer pavement temperaures and frost modelling

Abstract: Three papers form the present thesis. In paper I a numerical model for calculation of surface temperatures on a highway is presented. The model takes all relevant factors into consideration, i.e. conduction, wind, short- and long wave radiation. Temperatures obtained by the model are compared with those measured in a highway pavement. A good correlation is obtained. The model is using the position of the sun as input data and is not considering noon time conditions all the day, as in many other models for surface temperature calculation. In paper II and III a simple numerical model for calculation of frost depth and frost heave in highways is presented. Calculation results are compared with data obtained from two different test sites. Comparison is also made to laboratory tests conducted by using a new laboratory-testing device, developed by the author. The equipment is described in paper III. It is further argued, that frost heave to great extent is caused by ice lenses formed by water from the pores in unfrozen soil and only to a minor extent by water taken from the ground water, which is normally assumed. Good correlation is found between calculated and observed frost penetration and frost heave, in both field and laboratory condition. Special attention is paid to the influence of heave rate and water intake rate.