A concrete screw is a special type of screw designed to cut threads directly into concrete without shattering or breaking. Install a concrete screw by first drilling a hole at least one-half inch longer than the screw's length into the concrete, then slowly turning the screw into place using a drill or screwdriver.
Normal masonry screws are heat hardened, allowing them to screw into brick or stone without breaking or bending. Because concrete is much harder than either brick or most types of stone, concrete screws must be even harder than regular masonry screws. Unfortunately, hardening an entire screw sufficiently to screw into concrete makes the steel so brittle that it shatters easily.
Concrete screws only have hardened threads, while the screw's shaft is regular untreated steel. The hardened threads allow the screws to cut threads directly into concrete, while the untreated shaft can withstand the torque of a screwdriver or drill without shattering.
Before concrete screws were introduced, fastening screws into concrete was a much more difficult process. In the old process, the technician used a hammer drill to create a hole in the concrete. She then inserted a plastic anchor into the concrete before finally fastening the screw into the anchor. Not only was this process more difficult and time consuming than using concrete screws, but the plastic anchor was much less secure than an actual screw.