Chemical anchors are composite anchor cartridges which consist of a synthetic resin, fillers, thixotropic agents and a hardener component. The synthetic resins are unsaturated polyester resins, epoxy acrylate (known also as vinyl ester resin), and pure epoxy. The hydrophilic grade AEROSIL® 200 is used as thixotrope in unsaturated polyester resin applications, whereas the hydrophobic grades AEROSIL® R 202 and AEROSIL® R 208 are used in epoxyacrylate, polyurethane and pure epoxy applications. During the exothermal curing, the high degree of thixotropy and high yield value of the reaction resins prevent sagging on sloping or vertical surfaces during application. The AEROSIL® grades function additionally as anti-settling agents and prevent the settling of fillers in the cartridges during storage.