8.2 Concrete and Masonry Construction

Concrete is a mixture of cement, sand, aggregate and water in set proportions, which hardens to a strong, stony consistency over time. Masonry is the stone or brick work of a building. The construction standard for concrete and masonry applies together with other provisions of the construction and general industry standards.

Hazards

• Formwork collapse, from poor design, bracing or removal.
• Impalement and cuts from reinforcing steel.
• Struck by loads, buckets, pumps and hoses.
• Silica dust from cutting and grinding concrete and masonry.
• Skin burns from wet concrete.
• Collapse of masonry walls that are not braced.
• Caught in or between from jacks, mixers, hoppers and conveyors.

Concrete placing and equipment

• Workers must not apply a cement, sand and water mixture through a pneumatic hose unless they wear protective head and face equipment.
• Bulk storage bins, containers and silos must have conical or tapered bottoms and mechanical or pneumatic means of starting the flow of material. No one may enter a storage facility unless the ejection system has been shut down, locked out and tagged.
• No one may service or repair equipment such as compressors, mixers, screens or pumps where it could start unexpectedly unless all hazardous energy sources are locked out and tagged.
• Protect the ends of reinforcing steel that stick out where workers could fall on them with caps or guards.
• Guard the moving parts of mixers and conveyors, and keep people out from under buckets being moved.

Formwork

Formwork must be designed, made, erected, supported, braced and maintained so that it can carry, without failure, all the vertical and lateral loads that may be put on it. Formwork that conforms to the appendix of the standard meets the requirement. Drawings or plans, with all revisions, for the jack layout, formwork including shoring equipment, working decks and scaffolds must be available at the job site. Forms are removed only when the concrete has gained the strength needed, as shown by the plan or tests.

Materials

The most common material for concrete forms is plywood, although hardboard, strip boards, steel and reinforced plastics are also used. Plywood grades run from A, which has a sound, tight veneer free of knots and defects, to D, which has solid knots up to two and a half inches. Plywood labelled "concrete form grade" has been edge sealed and mill oiled.

Masonry

• Set up a limited access zone along the wall that is being built, and keep it clear of all but essential workers.
• Brace walls over 8 feet high until they are permanently supported, so that they cannot fall in the wind or from other forces.
• Have a qualified person check concrete structures before loads are placed on them.
• Do not exceed the lifting capacity of a lifting device.

A study aid, not published or endorsed by IOSH or OSHA. Laws and limits differ between countries.