A corrosion protection device, in particular a corrosion protection adapter, at least for a protection against corrosion at least of an end region of a geotechnical anchor element, which is in particular realized of a corrosion-sensitive metal or of a corrosion-sensitive metal alloy, for example of a construction steel or a concrete steel, includes at least one sleeve element which is configured at least for a mounting on the geotechnical anchor element, encompassing the end region of the geotechnical anchor element at least in a circumferential direction of the geotechnical anchor element, wherein the sleeve element is made at least largely of a corrosion-resistant metal and includes at least an outer thread.

Rock anchors, such as those described herein, allow for substantially complete draining of fluids from interior volumes of the rock anchors. In various situations, corrosive fluids may be introduced to the rock anchor, including inflating the rock anchors and during normal use, such as by groundwater intrusion. The rock anchors described herein include multiple passages for more effectively draining fluid from the rock anchors during inflation processes and during general use.

Rock bolts comprising an expandable tube having a longitudinally extending depression disposed between two curved outer portions of the tube, wherein the depression defines a channel having an opening defined between the two curved outer portions of the tube and the width of the opening is at least 10% of the width of the tube and/or a coating layer covers at least a portion of the expandable tube. Also, a method of manufacturing a rock bolt comprising forming an expandable tube comprising a longitudinally extending depression disposed between two curved outer portions of the tube, crimping a proximal end of the tube to form a crimped portion, and placing a sleeve around the crimped portion. Prior to crimping, a temporary spacer is placed in the channel in a portion of the tube adjacent to the portion of the tube that will be crimped.

A strand (20) for a cable bolt (14) comprises a plurality of metallic elongated members (22, 24) twisted together. At least one of the elongated members has a corrosion resistant coating (54) and surface deformation, so as to improve the bodig efficiency and the anchorage of the strand.