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The use of cement and concrete has frequent problems and drawbacks. One such problem is frost damage. If there are fine cracks in cement, water is able to get inside and freeze. When it freezes, it expands, causing the cracks to widen. Next time, more water is let in and the crack widens. Eventually the block of cement is ruined. Another common problem with cement and concrete is corrosion. Corrosion can creep up out of nowhere, this is caused by inclement weather and harsh conditions such as high stress. What happens with corrosion is that the piece of cement gradually begins to deteriorate from the surface, and eventually you have no cement or concrete. This is probably the most common problem with concrete and cement. Craze cracks are another serious problem. They are random cracks or fissures caused by shrinking and warping (Maslow 104). It appears on the surface of cement or concrete. Crumbling occurs due to the age of the concrete. When the concrete is very old, the hydration reaction begins to stop, and the concrete stops getting harder. It begins to crumble. Scaling is flaking of a finished surface of hardened concrete resulting from constant exposure to freezing and melting (Michaels). There are also environmental concerns involved with obtaining and creating cement. Blasting to quarry the raw materials can harm the land being blasted. The explosion causes loud sound emissions, which can disrupt local wildlife. The vibrations from the explosions can also disrupt local wildlife. Dust is also released during blasting. It can pollute the atmosphere. Kiln emissions are also a major environmental concern. When heating limestone, it gives off CO2, a greenhouse gas (Barr et al. 80). A greenhouse gas is a gas that traps heat in the atmosphere, causing global warming. It has become such a problem that a new substance called flyash is actually being used in the place of cement and concrete (80). It is a waste created by smokestacks where coal is burned (80). It is usually dumped in landfills. Using it cuts down on garbage waste, and does not require giving of CO2. It also is a better substance than cement. It tends to fill up the holes that cement leaves, which contribute to problems involving craze cracks (80). |
