Sounds like chemical anchor, which is a 2-component epoxy. I used that when installing anchors on my roof to use for abseiling. Did that because my life depended on it. But otherwise I try to avoid chemical anchors because they cannot be removed later. I could get out an angle grinder at that point, but there may be a day when I decide to remove all the render to expose the natural brick, in which case the anchor would always be an eyesore.