996 resultados para ombrophilous dense forest
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Much effort is being expended by various state, federal, and private organizations relative to the protection and preservation of concrete bridge floors. The generally recognized culprit is the chloride ion, from the deicing salt, reaching the reinforcing steel, and along with water and oxygen, causing corrosion. The corrosion process exerts pressure which eventually causes cracks and spalls in the bridge floor. The reinforcing· has been treated and coated, various types of "waterproof" membranes have been placed on the deck surface, decks have been surfaced with dense and modified concretes, decks have been electrically protected, and attempts to internally seal the concrete have been made. As of yet, no one method has been proven and accepted by the various government agencies as being the "best" when considering the initial cost, application effort, length and effectiveness of protection, etc.
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The use of deicing salts in this part of the country is a necessity to remove ice from our bridges. The use of these salts has always been a problem since the chloride-ions penetrate the concrete and reach the steel and cause corrosion which eventually cause deterioration of both the steel and concrete. One method used to try to prevent this from happening was to apply a waterproof membrane to the concrete after it was placed. This method did help, but was not cost effective as the longevity of the membrane system was of relatively short duration. For this reason, this research project was initiated. After the original deck was placed a second layer of concrete about 1 1/2" thick was placed on top. Biennial evaluation of the decks included testing for delaminations and steel corrosion. Cores were also obtained for a chloride analysis. Testing and observations showed the two-layer bridge deck to be effective in preventing corrosion. Since the time this project was initiated, epoxy steel has been introduced and is a cost effective way to protect the steel from corrosion.
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The State Forest Nursery welcomes the opportunity to help you with your tree planting needs. Our goal is to provide low cost, native seedlings in order to help make your tree planting successful and affordable. We strive to produce the best stock in the industry, and our staff will do everything they can to help you achieve your planting goals. We want your tree planting to be successful, so please let us know how we can help! You can contact us www.iowatreeplanting.com By planting trees today you will leave a legacy for your children and grandchildren, as well as a legacy for your home state, its people and its habitat. Let us help you leave your mark on the state you love- your children and grandchildren will thank you!
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