Capsules containing cementitious compositions

Claim 1

An anchoring capsule for use in anchoring, comprising a container, a dry self-setting water activatable solid composition in said container, said container having a plurality of holes whereby when the capsule is immersed in water the water passes through the holes into the container there to interact with said dry solid component in the container to form the anchoring self-setting composition, said container including means to reduce loss of the self-setting composition via the holes when the capsule is immersed in the water, and wherein the dry self-setting composition in said container is a cementitious mixture comprising a high alumina cement, said dry self-setting composition including both an organic acid component selected from the group consisting of hydroxy carboxylic acids and alkali metal salts and esters thereof, and at least one water soluble lithium derivative, said organic acid component and said lithium derivative being present in substantially equal proportions by weight, and in which there is a concentration of 0.05 parts of the lithium derivative to 100 parts of dry self-setting composition which is sufficient to cause the self-setting composition to achieve a high early strength in the form of a controlled initial setting time followed by a final setting time to give a final strength similar to the high initial strength whereby an element may be anchored in the set anchoring composition.