Acta Scientiarum Polonorum

Abstract: The paper presents the issue concerning the examination of the load index CBR ground for questionable land. In accordance with applicable regulations in the case of soft soil should always be done CBR study, regardless of the water – groundwater. In the current engineering practice, despite the Regulation on the technical conditions for highways, laboratory tests CBR native land are rarely performed. Markings index CBR made for different levels of the stress of the primary structural layers and land with different fractions of silt. The obtained results were correlated with the burden of the weight of structural layers of pavement in accordance with the new catalog of flexible pavements and semi-rigid. In addition, it shows the relationship between an indicator of the CBR and the content of silt fraction.