Use Corrosion Inhibiting Admixtures for Long Term Concrete Durability
- Construction Specifications Should Require a Corrosion Inhibitor.
- Use Life 365 to Understand the Value of Different Corrosion Protecting Methods
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Life 365 Demonstrates that Lowest Life-cycle Cost Is Obtained Using a Corrosion Inhibitor
| Before construction the cost of different mix designs should be compared using Life 365 . |
Durability of Concrete Used in Roads, Bridges, Parking Garages, Wastewater Treatment Plants, Port Facilities and Other Structures Increases when a Corrosion Inhibitor is Used. |
| Why use a Concrete Corrosion Inhibitor? |
The corrosion inhibitors available today from the major admixture supply companies (see list at the end) have all been tested using ASTM, AASHTO and/or special proprietary tests to show their effectiveness. These inhibitors have also been tested by independent and government laboratories. These tests confirm that corrosion inhibitors extend the usable life of concrete structures subjected to harsh environments.
The results of these tests are available in publications listed on our web site or through the companies listed at the end of this Newsletter. Several years ago, good results were reported when epoxy coated rebars were tested for a two year period. When the testing time was extended the results were disappointing. The report on these results is also listed on our website. See article by K. Clear.
The most cost effective way to obtain concrete that will last more than 75 years is to specify the use of a corrosion inhibitor with a supplementary cementitious material such as fly ash or slag. In this way, reinforced concrete subjected to road salt or built along the seacoast will be durable.
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| Admixture Compatibility |
Other admixtures are used in concrete to control the set time, reduce the amount of water, improve the freeze-thaw resistance, control cracking, and improve fluidity. When these are used in conjunction with a corrosion inhibitor the proper dosage of each should be tested with the corrosion inhibitor and then adjusted. Other properties, such as color and finishability, should be similarly addressed. The overall performance of concrete with several admixtures is seldom a linear function of individual products, and experience is the most reliable way to predict field performance.
It is important that the company certify that the corrosion inhibitor will be compatible with other admixtures used in the concrete. In addition, it is also advisable to add the admixtures separately, and carefully follow the suppliers' instructions.
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| Life-365 |
The mathematical model Life 365 is available on our web site and can be used to estimate the service life and determine the life-cycle cost. Although a competitive advantage is built into the model for epoxy coated rebars, the model demonstrates that concrete constructed with a corrosion inhibitor lasts longer, at a lower life-cycle cost, than other methods of protection.
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| CCIA Assistance Available |
The members of the Concrete Corrosion Inhibitors Association: Axim Concrete Technologies, Euclid Chemical Company, Grace Construction Products, BASF Admixtures (Master Builders), and Sika Corporation are major admixture suppliers. They produce and sell corrosion inhibitors that have been proven to protect concrete in severe environments for many years.
See our web pages at www.corrosioninhibitors.org or call us at 301-340-7368.
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