Analysis of the results of model investigation of water capillary rise in road embankments

Abstract

The durability of engineering objects, including roads, depends on proper recognition of natural reactions undergoing in soil. One of this kind of processes is soil swelling, which is very important for highway engineering. It was proven that it can be effectively limited by decrease in the height of ground water capillary rise. This paper aims not only at presenting the results of model research in ground capillarity and relations between the height of capillary rise and a kind of soil in a road embankment, but also examines a type and concentration of a solution migrating in a embankment. Natural aggregate, occurring in three deposits in the area of Zielona Góra of different origine, was tested. The research was focused in the height of capillary rise in naturally grained aggregate and in particular fractions of aggregates. At the same time water capillary rise and the solutions of different chemical compounds commonly used in winter roads maintaining i.e.: sodium chloride and calcium chloride, with concentration 5% and 10%, was analysed. The analysis of capillary rise in particular soils, depending on a type of a capillary compound and its concentration, was presented as analysis of triple factor variance with second order interaction. The conducted research proved that the ground water shows the maximum height of capillary rise. The saturation of ground water with chemical compounds used in winter roads maintenance (NaCl and CaCl₂) and increase in concentration of those compounds (from 5% to 10%) decreases the capillary rise considerably as well as swelling. The presented results show the possibilities of reduction of the negative effects of soil swelling by an appropriate selection and concentration of chemical compounds used in winter maintenance of roads.