Concrete cracks have been around since concrete was invented. Look back through the years at some different methods of addressing the problem.
1950s: Control of Cracks in Reinforced Concrete
Detailed information on the cracking of loaded concrete beams and slabs is now available as a result of recent investigations at the National Bureau of Standards. The tests results promise to prove useful in controlling the spacing and width of cracks in the future design of reinforced concrete structures. In general, the results show that width of cracks can best be controlled by using a large number of small reinforcing bars and by increasing the reinforcement. While cracks barely wide enough to be visible may be objectionably only because of appearance, cracks of greater width can be dangerous because of the possibility of corrosive agents attacking the steel reinforcing bars. Excessively wide cracks can also result in leakage in dams, tanks, and pools. The Bureau findings- that is, by increasing the bond strength between concrete and steel with improved reinforcing bars, widths of cracks may be reduced- will therefore make a significant improvement in reinforced concrete structures.
1960s: Concrete Repair Problems: Causes and Cures
All materials, of course, deteriorate in some measure from the ravages of time, exposure to the elements, and the effects of wear and tear. All factors considered, the performance of concrete compares favorably with other structural materials. The correct technique and material for a job depend on the extent of damage, the function of the structure, the availability of equipment and skilled manpower, the expected traffic or adverse environment, the time allotment, the importance of appearance and the available funds.
1970s: Epoxies for Concrete Repair and Restoration
Replacement of concrete buildings, bridges, roadways and other structures is becoming more and more expensive as costs of materials and labor continue their upward spiral.
1980s: Four Steps to Successful Concrete Repair
To participate in repair and rehabilitation successfully, the contractor must pay close attention to four basic steps in the repair process--evaluation of causes, extent, and consequences of deterioration; selection of repair material; preparation for repair; and placing of repair material.
1990s: Crack-Sealing Basics
Routing and sealing is a common crack-repair method in which the crack is made wider at the surface with a saw or grinder, and the resulting groove is filled with a flexible sealant. This prevents water and debris from entering the crack yet allows the crack to open and close in response to loads or changing temperatures.
2000s: Extreme Crack Repair
Concrete cracks because it can resist tension only about 1/10 as well as it can resist compression. But the concrete often finds itself in tension as well as compression. This typically happens when the concrete bends, such as in a beam or floor slab, and when it shrinks as it dries. Anyone in the field knows this and uses many different methods to help concrete elements resist tension.
2010s: Preparing Concrete for Durable Repairs
Performing each concrete repair efficiently and effectively calls for a particular set of skills, materials, and equipment. The repair must be structurally reliable, visually acceptable, and durable.