alpha,omega-Dihydroxyoligo(butylene-ethylene adipinate) (Poles 55/20) was reacted with diphenylmethane-4,4-diisocyanate at 80-90 degrees C and 200 Pa, stabilised with o-phosphoric acid, filled with ceramsite (1-15% by mass) at 60 degrees C, mixed with 1,4-butanediol soln. of 1,4-diazabicyclo[2,2,2]octane catalyst and poured into steel casts at 22 degrees C or 70 degrees C. As an alternative, the prepolymer was poured into a preliminarily heated ceramsite in the cast. After gelation, the composites were crosslinked at 110 degrees C for 6 or 18 h. The samples produced were studied for tensile strenght, Shore hardness, Schob elasticity and density. The tensile strenght (10.2-27.8 MPa) and density (1.077-1.366 g/cm(3)) decreased with increasing content of ceramsite in the composite material. The hardness (71.6-88.3 degrees ShA) and elongation at fracture (420-940%.) showed mins. at qbout 10% of ceramsite. The crosslinking time had not any effect on the composite properties.