COMPLIANCE INFO_1968-2006 - Laserfiche WebLink

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114 February, 1968 SA 1 SA 1 terioration of structural materials. Some of theproducts of organic decompo- sition are highly corrosive, such as organic acids and hydrogen sulfide gas consi in the presence of water. Materials such as cinders react with water to form in the Ga weak acids which attack metal and can cause deterioration of concrete. Some industrial wastes are detrimental to the piles and structural materials. the f: 1r nothir. Steep is the most seriously affected. In one case, steel pipe was used be- 'fi neath a one-story building placed on the sanitaryland fill. mock actions reduced the pH of the material' to approximately 4T The electrical touch ' Str resistivity of the soil-fill mixture beneath the structure ranged between 800 ohms and 3000 ohms per cu cm. (By way of comparison, the research memb work of the U. polyetl S Bureau.of Standards indicates that soils are highly corro- v sive when their electrical resistivity is less than approximately 2000 ohms fill, per cu cm.) Within a year the galvanizedremov piping was so badly pitted that most of it was unserviceable. Because it was under the structure, replacement fill ha: involved a considerable cost which, incidental) was aid tively, fill architect and his mechanical engineer. Steel it i by the designing design g piling driven through sanitary fills has been subject to severe pitting and deterioration although there is beneat, no record of their failure from corrosion. In one instance, however, a'steel precau sheet piling wall was so badly attacked that it was weakened to the point of partial failure. The organic acids present in decomposing garbage,wood,and paper inhibit ,r the setting of portland cement. When concrete is poured in mass, this does not appear to be destructive. However, when cement is mixed with the soil to form a soil-cement road base, the organic materials can prevent the develop- Con, meet. of the necessary strength in the mixture. Concrete deteriorates rapidly conside in the presence of the sulfate ion. There are no published records of this irregul d occurring in sanitary land fills, although it maybe a serious problem in some materia ' industrial wastes. The acids• present in many sanitary land fills can cause as autc surface deterioration of the concrete. If acid concentration is sufficient, the the use reinforcing steel will be exposed, and thereupon rapid deterioration will Deep e follow because of the expansion of the corroding metal. earthen Piping and foundations which are in contact with the waste materials and shovels with the soils immediately in contact with the waste must be designed for sizes n resistance to deterioration. Steel piping must be properly wrapped with cavatior corrosion-resisting coatings. If possible, steel piling should be avoided unless A ma it is encased in concrete within the fill. Concrete piling should be adequately As soon protected by a liberal cover of reinforcing steel with high-density concrete vated an ing prof and, where necessary, sulfate-resisting cement utilized. Gas Generation.--Gases are generated by organic decomposition and, in An exca rare cases, by chemical reactions within the fill. The principal gas formed had rep by biologic decomposition is methane, although, in some cases, hydrogen work in sulfide is produced in the early stages of decay. Because of the porous nature of the we of the' fill, gas will accumulate within it and slowly escape through the soil In on. cover. There are usually numerous pockets and openings in and around strut- fide in tures where the gases may accumulate. and present a serious explosion hydroger. hazard. Gas accumulation in the soil can have a poisoning effect on landscape strong tk vegetation. In fact, stunted vegetation can be an indication of gas release. In Found one case, the presence of gas killed expensive shrubbery which was placed obstructi around a structure. Finally, gas in a fill can present a health hazard. In one tion is c instance, the occupants of the first floor of a small apartment building on altogethe -sanitary land fill developed a sickness which could not be diagnosed. After blasting ing sligI : a