Summary:

Ground-cement composites are commonly used in public road foundations constructed also in forested areas. Layers of cement stabilized ground are utilized in road construction as improved basement soil or basic foundation. Compacted cementground composite layers are independently utilized as road surfaces, surfaces of fire emergency airports, manoeuvre areas,forest car parks, wood depots and peat-lands surfaces in forest road construction. A relatively low percentage of the binder brings about a fairly high permeability of the utilized cement-ground and makes it more susceptible to flaking and cracking, as well as inflitration by precipitation water. The cements contain, apart from Portland clinker, other non-clinker mineral components, mainly industrial refuse. The source of chemical pollution of the cement binders may originate from materials and substitute fuel (e.g. industrial and domestic refuse). The general objective of the project was to evaluate the influence of cementground composite road foundations on the roadside ecotone zones in the fresh mixed broadleaved forest. The carried out investigationsaimed at recognizing the process of washing out of chemical compounds from foundations depending upon the applied cement and condition of the foundation. Five types of different cements with a different share of non-clinker components (fly-ashes and blast furnace slags) were used for stabilization of the experimental sections. Chemical tests of the eluates from cements and cement-ground composites proved that chromium is the element which is as the first one leached from the cement- ground foundations. Defining the chemical forms of chromium occurrence deciding about mobility and availability, its possible impact on the forest ecosystem can be described. The aim of the presented research was defining the participation of respective chromium forms in humus horizons at the forest edge and in the distance of 10 m. from the crown edge: 5 experimental sections stabilized with different types of cement and the control section. The carried out investigations proved that the sections reinforced with the tested cements had no de-stabilizing influence on the natural balance of the roadside ecotone zones of the fresh mixed forest. Speciation analysis carried out applying the sequence extraction method proved that chromium occurred mainly in the