Concrete block

The use of blockwork allows structures to be built in the traditional masonry style with layers (or courses) of staggered blocks.

In the western United States, where they are easily obtainable, porous lava rock gravels are used for weight reduction.

They also have an added decorative effect to certain types of block, such as split-face, due to their distinct red and black colors.

A core also allows for the insertion of steel reinforcement to span courses in order to increase tensile strength.

[12] Cores may also be filled with expanded-polystyrene (EPS) block foam insulation, substantially increasing the R-value of the resulting wall to be in compliance with the US national energy code.

[14] Concrete blocks may be formulated with special aggregates to produce specific colors or textures for finish use.

Additionally, steel reinforcement bars (rebar) can be used both vertically and horizontally inside a concrete block wall to maximize its structural performance.

For this reason, high-seismic zones typically allow only fully grouted walls in their building codes.

[17] The compressive strength of concrete blocks and masonry walls varies from approximately 3.4 to 34.5 MPa (500–5,000 psi) based on the type of concrete used to manufacture the unit, stacking orientation, the type of mortar used to build the wall, and whether it is a load-bearing partition or not, among other factors.