Expansion of concrete pavements with small-radii curves can create radial forces large enough to move houses, according to the author, a consulting professional engineer who has seen this phenomenon many times. The situation can occur when summer temperatures expand a curved concrete pavement more than enough to close the contraction joints. The resulting radial force tends to move the pavement and any objects abutting it at the outside of the curve. These objects can be curbs, driveways and even houses at the opposite ends of the driveways. Pictured is a dramatic example of a slab-on-grade house with a very wide diagonal crack through the kitchen floor. The crack was actually created by expansion of the street outside the home, which produced enough force to push the driveway against the garage floor and the garage floor against the slab.
Certification programs fit into two main categories: plant certification and personal certification. Prestressed, precast, and ready mixed concrete producer associations have established programs requiring thorough inspections of production facilities. The inspections are conducted by impartial, professional engineers who are qualified to certify that the plants have properly calibrated and maintained equipment that can produce and deliver concrete and concrete products that meet industry standards and project specifications.
Parking lots are a cost effective alternative to asphalt that saves owners money in lifetime costs. To encourage good construction of concrete parking lots, the American Concrete Institute (ACI) formed Committee 330, Parking Lots, in 1982. The committee's first document, "Guide for Design and Construction of Concrete Parking Lots," was published in December 1987.
Today it is possible to introduce additional efficiencies in concrete construction by combining precast concrete with cast-in-place. To take advantage of these efficiencies though, the building owner and his designer must modify some of the traditional procedures for designing and constructing buildings.