PROPERTIES of CEMENT
· Not permeable. Creates a sealed surface that does not allow vapour passage. · Rigid. Requires expansion joints to allow 1) _____ natural earth movement without cracking. · Hard. A great property 2) _____ the right place but often cement is too strong for the materials it is used with. · Waterproof. Completely seals mortar joints or walls. · Susceptible 3)_____ frost. Will crack in very cold conditions and therefore if used in foundations, needs to be in deep trenches that make contact with the warmth 4) _____ the earth to avoid problems associated with frost heave. · Attracts moisture. Other materials around cement need to be protected 5) _____ it as it holds water and can cause rot to develop. · Does not deal 6) _____ moisture. Can cause condensation problems in bathrooms, kitchens, bedrooms etc. as it does not regulate moisture. · Does not have a long history. It was invented in the mid 19th century and began to be used extensively 7) _____ 1930 onwards. We are seeing some major damp and durability problems now, caused 8) _____ the inappropriate use of cement from 50 or so years ago e.g. collapse of cob walls re-plastered with cement, the need to re-inforce some motorway bridges, excessive cracking in town houses leading 9) _____ difficulty in re-selling. · Causes green house gas effect. The manufacture of cement is one of the major causes of the green house gas effect globally as it releases tonnes of carbon dioxide 10) _____ the atmosphere, none of which is re-absorbed by cement plaster.
12 Find and correct 10 mistakes: Hydraulic Lime can be made in two ways: 1. Fat lime or puty lime, maded from quicklime, with a pozzolan aded to it, to make the lime hidraulicby artificial means. The Romans used pumice or others volcanic rock but ground up brik dust can also bee used. 2. Naturally occurring hydraulic lime, that is producing from limestone that is high in silika (clay) and alluminum, is slaked and used straight away. 13 Translate into Russian without a dictionary: LIME Limes may be divided into three distinct classes: 1. Rich limes that contain no more than 6 percent of impurities, slake very rapidly, and entirely dependent on external agents for setting power (от внешнего фактора для застывания). These are widely used for interior plasterer’s works. 2. Poor limes that contain from 15 percent to 30 percent of useless impurities and possess the general properties of rich limes, only to a lesser degree. 3. Hydraulic limes that contain certain proportions of impurities, which when calcinated, combine with the lime and endow it with the valuable property of setting under water or without external agents. Lime is one of the basic building materials extensively used all over the world.
14 Listen to Rick Bohan who speaks about cement and concrete. Answer the questions below (1-6): 1. What does Rick Bohan do? 2. What are the elements of making cement? 3. Can you describe the process of making cement? 4. What is the difference between cement and concrete? 5. What is the primary ingredient in concrete? 6. Why is cement called Portland cement?
15 Watch the video and present the main idea of each episode in 4-5 sentences using the expressions from Appendix 2.
16 Render the text in English using the expressions from Appendix 2:
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