In A Corrosive Environment, High Performance Concrete Must Contain A Corrosion Inhibitor.
- With Proper Care Concrete Cracking Can Be Reduced to the Point Where It Does Not Impact Durability.
- The Method of Cost Analysis in Version 2.0 of Life 365 Has Been Greatly Improved.
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Life 365 Demonstrates That Using a Corrosion
Inhibitor Produces the Lowest Life-cycle Cost.
| Comparison of Costs of Different Methods of Construction with the New Life 365 Version 2.0 is More Reliable, Since It Is Based on Probabilities. |
Corrosion Inhibitors Are Selected for Roads, Bridges, Parking Garages, Wastewater Treatment Plants, Port Facilities and Other Structures Because of Lower Cost and Better Durability. |
| Concrete Cracking Control |
Cracking in concrete results from three general causes. The first is shrinkage, related to water evaporation and thermal effects. Good mix design and curing procedures will minimize this. The use of water reducing agents, fibers and shrinkage control admixtures also help to reduce shrinkage from these causes.
The second is structural cracking. Concrete is a brittle material and some cracking is inevitable. However, this source of cracking can be minimized by proper structural design and taking care not to overload the structure. It has been shown that if cracking is controlled, the diffusion of salt into the concrete is same as uncracked concrete
The third type of cracking comes from expansive chemical/physical reactions like frost action and the alkali -aggregate reaction. Of course, corrosion of the reinforcing steel is also a consideration here.
No other process (painting the
rebars) can produce durable concrete like the use of a corrosion inhibitor and the proper control of the causes of cracking. The value of a corrosion inhibitor is clearly demonstrated in Life 365.
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| New Cost Prediction Model |
An industry consortium (NRMCA, CCIA, SCA and SFA) funded the development of a second generation of the mathematical model (Life 365) for the comparison of different methods to protect concrete from corrosion. This new version of Life 365 was developed by Mark Ehlen at Sandia and Evan Bentz at the University of Toronto. It will be based on probabilities and have an improved method for determining the life-cycle cost of concrete.
The user will be able to specify starting time, duration of cost evaluation, and costing as a function of the concrete service life. In this way several means of protecting concrete can be studied to find the lowest life-cycle cost and the greatest trouble free lifetime of concrete. The new version was presented at the Committee 365 meeting of ACI this fall. Previous versions of this model have been used by many organizations, including state departments of transportation.
Life 365 Version 2.0 will be available from the CCIA web site early next year.
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| CCIA Assistance Available |
The members of the Concrete Corrosion Inhibitors Association: Axim Concrete Technologies, Cement Chemistry Systems, LP, Euclid Chemical Co., Grace Construction Products, Degussa Admixtures, and Sika Construction Products are major admixture suppliers which produce corrosion inhibitors that have been tested and sold for use in severe conditions for many years. See our web page www.corrosioninhibitors.org
or call us at 301/340-7368
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