Compositions crosslinkable by condensation reaction, comprising at least one organosilicon compound having at least two condensable radicals, at least one finely divided silicon dioxide having a BET surface area of 30 to 120 m 2 /g determined in accordance with DIN ISO 9277/DIN 66132 and a relative thickening effect η rel of 1.4 to 10, where thickening effect identifies the dynamic viscosity in mPa·s of a dispersion at 25°C, as determined using a rotational viscosimeter (RS600 from Haake, DIN 53019 measuring system, cone/plate, C60/2 Ti) at a shear rate of 10 s -1, and the "relative thickening effect" η rel is the ratio of η to η 0, where η corresponds to the dynamic viscosity of the liquid with silicon dioxide, and η 0 to the dynamic viscosity of the pure liquid without silicon dioxide: η rel = η/η 0, and the dispersion is obtained by incorporating 4.5 g of silicon dioxide powder into 145.5 g of a styrene solution of an unsaturated, isophthalic acid-based polyester resin, said solution having a dynamic viscosity of 1000 ± 100 mPa·s at 23°C and a styrene mass fraction of 34%, measured in accordance with DIN 16945, 4.14 (available commercially under the name Palatal ® P6 from BASF SE, Ludwigshafen, DE), with stirring at a temperature of 23°C in a 0.5 1 beaker, and then carrying out dispersion using a dissolver (Pendraulik laboratory dissolver LD 50 with 40 mm toothed disk) at 2800 min -1 for 5 minutes, and the distance of the dissolver disk from the bottom of the beaker in this procedure is approximately 20 mm, and, in the course of the dispersing procedure, the beaker is covered with a drilled lid, and at least one hydrocarbon component which has an initial boiling point above 150°C, a final boiling point below 350°C, each at a pressure of 1013 hPa, a kinematic viscosity of 1.5 to 6.0 mm 2 /s as measured at 40°C in accordance with ASTM D 445-12, a viscosity-density constant of less than or equal to 0.820, a pour point of less than -5°C, and an aromatic carbon atom (C A) content of less than 0.1% C A, where the initial boiling point and the final boiling point are each determined according to ASTM D 86, the viscosity-density constant is determined in accordance with ASTM D 2140-08, where the relative density needed for the calculation of the VDC is measured at 15.6°C in accordance with ASTM D 1481-12, and the pour point is measured in accordance with ASTM D 97. at least one organosilicon compound having at least two condensable radicals, at least one finely divided silicon dioxide having a BET surface area of 30 to 120 m 2 /g determined in accordance with DIN ISO 9277/DIN 66132 and a relative thickening effect η rel of 1.4 to 10, where thickening effect identifies the dynamic viscosity in mPa·s of a dispersion at 25°C, as determined using a rotational viscosimeter (RS600 from Haake, DIN 53019 measuring system, cone/plate, C60/2 Ti) at a shear rate of 10 s -1, and the "relative thickening effect" η rel is the ratio of η to η 0, where η corresponds to the dynamic viscosity of the liquid with silicon dioxide, and η 0 to the dynamic viscosity of the pure liquid without silicon dioxide: η rel = η/η 0, and the dispersion is obtained by incorporating 4.5 g of silicon dioxide powder into 145.5 g of a styrene solution of an unsaturated, isophthalic acid-based polyester resin, said solution having a dynamic viscosity of 1000 ± 100 mPa·s at 23°C and a styrene mass fraction of 34%, measured in accordance with DIN 16945, 4.14 (available commercially under the name Palatal ® P6 from BASF SE, Ludwigshafen, DE), with stirring at a temperature of 23°C in a 0.5 1 beaker, and then carrying out dispersion using a dissolver (Pendraulik laboratory dissolver LD 50 with 40 mm toothed disk) at 2800 min -1 for 5 minutes, and the distance of the dissolver disk from the bottom of the beaker in this procedure is approximately 20 mm, and, in the course of the dispersing procedure, the beaker is covered with a drilled lid, and at least one hydrocarbon component which has an initial boiling point above 150°C, a final boiling point below 350°C, each at a pressure of 1013 hPa, a kinematic viscosity of 1.5 to 6.0 mm 2 /s as measured at 40°C in accordance with ASTM D 445-12, a viscosity-density constant of less than or equal to 0.820, a pour point of less than -5°C, and an aromatic carbon atom (C A) content of less than 0.1% C A, where the initial boiling point and the final boiling point are each determined according to ASTM D 86, the viscosity-density constant is determined in accordance with ASTM D 2140-08, where the relative density needed for the calculation of the VDC is measured at 15.6°C in accordance with ASTM D 1481-12, and the pour point is measured in accordance with ASTM D 97.