ArtPage on Concrete

concrete - In art criticism, concrete refers to things which are real, particular, tangible; as opposed to abstract. The more general use of the term refers to the concrete building material, which is extremely heavy and durable when set. First employed by the ancient Romans, it's made from a mixture of Portland cement, aggregate (typically sand and gravel), and water.

Concrete is typically poured into a form; very rarely modeled or carved. Slabs should be between four and eight inches thick, depending on their function. A basement floor: 4 inches; home garage floor or porch: 4-6; sidewalk: 5-6: driveway: 6-8. Concrete is sold by cubic volume. Calculate need as: slab thickness in feet x slab width in feet x slab length in feet = cubic feet of concrete. 27 cubic feet = 1 cubic yard. Large projects require steel reinforcing bars (called re-bar). The strength of concrete increases when the amount of cement in the mixture increases, the amount of water relative to cement decreases, the density of the concrete is higher, and the aggregate is coarser.

All dusts are WEAR SAFETY GLASSES! hazardous to WEAR A DUST MASK! breathe.

A user should wear an appropriate dust-mask and eye protection, or be very effective in preventing dust from damaging the workplace's atmosphere.

The most common problems encountered in making concrete are adding too much water or sand, and poor mixing.

The correct amount of water (by volume) should be about half of the total mixture. The more trustworthy gauge, however, is to add only as much water as makes the mixture workable.

For a pad or footings for outdoor sculpture, an excellent concrete mixture will be achieved at these ratios (by volume): 1 part cement, 1 part sand, 2 parts gravel; although 1:2:3 is suitable for most applications; and 1:2.5:4 is adequate for basic foundations.

Mixing the concrete is required in order to produce the strongest, most durable pour. When mixing concrete, mix the cement and sand first, then mix in the coarser aggregate.

Curing of concrete is necessary for the material to harden properly. After the pour, the concrete must be kept moist for a week, and the temperature must not drop below 50°F.

Jacqueline Scholten and Hannelore Holz are two contemporary Swiss sculptors who cast concrete figures and paint them.
Historical Timeline of Concrete.

Also see masonry and mortar.