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Cement debris has a typical density of about 2,400 pounds per cubic yard, about 60% of the cement’s in-place density. Since the weight of the actual cement mass has not physically changed, the reduced density is the result of air voids (which weigh nothing) taking up approximately 40% of the rubble 阅读全文
posted @ 2012-02-11 14:34
liajones
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Production rates for these crusher machines are impressive, with some of the larger mobile crushers able to handle over 600 tons per hour. At an in-place density of approximately 145 pounds per cubic foot, this is equivalent to almost 8,300 cubic feet—or 550 feet of a two-lane road having a 6-inch-t 阅读全文
posted @ 2012-02-11 14:26
liajones
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Excavation and HaulingExtra-heavy-duty and extra-large buckets are typically used for the excavation and removal of the broken cement debris. A specialized type of bucket, the riddle bucket (sometimes referred to as a shaker bucket) is used to separate large objects, such as bricks, rocks, or broken 阅读全文
posted @ 2012-02-11 14:18
liajones
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Breaking and EnteringBreaking up the in-place cement is the first step to excavating and removing it. This task is usually performed by hydraulic hammer attachments on standard earthmoving equipment, as well as by the smaller, manually operated jackhammers. Both machines direct their applied cyclica 阅读全文
posted @ 2012-02-11 14:08
liajones
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This steel is necessary since, though very strong when subject to compressive forces—cement is weak under tension loads (it is only one-tenth as strong in tension as it is in compression). Cement by itself tends to crack under loads or as the result of contraction and expansion caused by temperature 阅读全文
posted @ 2012-02-11 13:51
liajones
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When planning for the excavation and removal of old, in-place cement, two questions have to be asked. First, how much cement is there? Second, what kind of cement has to be removed?Mass excavation and trenching operations typically deal with natural soil and rock. These can present their own difficu 阅读全文
posted @ 2012-02-11 13:34
liajones
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Mining crushing machines are used widely in mining, smelting, building material, highway, railway, water conservancy and chemical industry and many other sectors. The commonly used mechanical crushing equipments are: jaw crusher, impact crusher, cone crusher, hammer crusher, vertical shaft impact cr 阅读全文
posted @ 2012-02-11 13:21
liajones
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After high-speed railway is an important direction for the development of railways, the railway is also the driving force for national economic development, from the annual Spring Festival we can 'glimpse', which is also stimulating domestic demand, promoting economic growth as a 'locomo 阅读全文
posted @ 2012-02-11 13:11
liajones
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Artifical sand-making technology has developed a long time in China. However, to make sand according to production requirements as well as being environmental friendly has for many years been a technological problem in sand-making field.There are two methods for traditional sand-making, dry technolo 阅读全文
posted @ 2012-02-11 11:39
liajones
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KATHMANDU: Crusher factories have shut down to protest the government's decision to hike export duty on boulders, stones and sand. They have vowed not to resume operations until the government revokes its decision.Citing the need for protecting the environment and domestic industry, Finance Mini 阅读全文
posted @ 2012-02-11 11:26
liajones
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