This paper presents the results of studies on crushing phenomena during the Proctor compaction test on Recycled Concrete Aggregate (RCA). Increase in demand for materials in road construction industry creates the need for new materials which can replace natural aggregates (NA). Moreover, it should be noted that NA are a non-renewable resource in opposite to, for example RCA which could be recycled and become a part of road construction. There are many material properties, which need to be clarifi ed and crushing phenomenon is one of them. The following article analyses the issue of crushing. Selected blends which differs by gradation curves were tested. Tests have been made according to Proctor's method in various moisture conditions. The paper ends with fi nal remarks for practical application of the RCA.
The crushing of the logging residues was carried out on a forest area, on a mixed fresh coniferous site (BMśw). The weight of the logging residues which were left behind on the clear cut area, after taking away the round wood assortments was 47 t. The object of the analysis was a Meri Crusher MJS-2.0 DT crushing machine powered by a Valtra T-190 tractor. The crusher was 2000 mm wide and the power of the tractor was 190 HP. During the analysis the quantity of the biomass to be milled and the productivity of the milling operation itself were determined. Based on given technical parameters of the crusher (the rpm of the PTO, number of cutters, diameter of the drum and the driving speed of the tractor), the rpm of the working drum, the linear velocity of the cutters, the power and torque of the working drum and the productivity of milling were determined. Based on the analysis of working movements of the machine, the total force on all the cutters as well as the average force per one cutter were calculated. It was found that the average force on one cutter was 770 N.