Concrete repair is the process of fixing a hardened concrete surface that over time has lost the ability to hold concrete materials together due to damage or exposure to the environment. Concrete repair is suitable for cracks, physical impacts, chipped surfaces or surface flaking. Cracks are sealed and epoxy is injected to restore strength. Lotus Contractors When a crack affects the performance of the structure, we then repair it to restore its structural properties.
Epoxy injection is often the basis of this type of repair, with or without added reinforcement. Injected epoxy is actually stronger than concrete and can restore the strength of the concrete, but if there is an underlying problem, such as an overloaded structure or some condition of movement, the concrete will simply crack again elsewhere. Combined, these documents provide guidance that elevates repair to the same level as the design and construction of new concrete structures. The industry recognised that too many concrete repairs were failing too soon.
The advice in these new resources provides a way to consistently produce durable concrete repairs. Understanding what is involved in repairing and restoring concrete and masonry structures is critical, as is being able to identify the warning signs of a minor repair that is on its way to becoming a major investment. The number one way to save money on concrete and masonry repairs is to budget for routine building inspections and ongoing maintenance from the outset, according to Bud Lampley, infrastructure specialist at Simpson Strong-Tie, a leading manufacturer of structural connectors. Many, if not most, types of concrete incorporate some material susceptible to ASR.
Corrosion of steel in concrete can be a major problem for many reinforced concrete structures if moisture is present. Select a repair material that provides the necessary material properties and can be placed by the most appropriate application method. DR JOHN BROOMFIELD is an independent consultant specialising in the corrosion of steel in concrete. Following these guidelines does not necessarily ensure a successful and lasting repair, but provides a system for making decisions based on the authors' many years of experience.
In the 1850s steel-reinforced ships and tubs were manufactured, and in 1854 William Wilkinson obtained a patent for a method of constructing fireproof buildings using iron strips embedded in mass concrete. ICRI-Glossary of Concrete Repair Terminology, International Concrete Repair Institute, Des Plaines, IL. Potential hazards include those arising from the working environment (heat, falls), the repair materials (concrete burns) and the equipment used. External reinforcement is usually done by bonding some type of flexible reinforcement, such as carbon or glass fibres, to the outside of the concrete element and then covering it with placed concrete, trowelled concrete or shotcrete.
The adequacy of thermal expansion coefficients is fundamental to the versatility of reinforced concrete. How long the repair is expected to last must also be considered when choosing the type of repair material to use. Any large patch or coating made of an impermeable material can trap moisture between the existing concrete surface and the seal made by the repair. Of particular concern today is the reaction of alkali silica in concrete and corrosion of reinforcing steel, both of which are affected by the alkalinity of Portland cement concrete.
If the concrete needs to be reinforced, various techniques are used, such as simply increasing the size of the concrete element and external reinforcement. The promise shown by the ECC therefore offers a potential solution to the global problem of rapidly deteriorating concrete infrastructure. Bill Palmer is editor-in-chief of Hanley Wood's Commercial Construction Group, which includes the digital and print versions of Concrete Construction, Concrete Surfaces, The Concrete Producer, Public Works and Masonry Construction.