CONSTRUCTION
Natural materials: earth, wood, stone, hemp, rush... are employed in construction.
Earthen walls:
- rammed earth: earth packed into formwork and earth/lime reinforcements.
- cob : pile of balls of earth generally mixed with plant fibre.
- daub : wooden frame and filling with earth, straw (and lime depending on the quality of the earth).
- adobe : clay brick formed in a mold and dried .
Earth is made up of grains of different sizes (pebbles, gravel, sand and fine particles) and depending on its clay and sand content, it can be used without addition in the manufacture of walls. cohesion taking place by settling.
In case it is too sandy it is possible mix it with another more clayey soil or add lime and if it is too clayey it is advisable to add sand.
Tests simple can determine the composition by mixing it with water and shaking it, the grains settle slowly in decreasing sizes.
The earth must be neither too wet nor too dry , we drop a ball of earth from its weight on the ground and depending on how it breaks or sticks we determine its content at the top.
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Lime or Cement, which is the best solution for construction?
June 21, 2016
Lime has many uses, from hydraulic lime or air lime , in particular that of being able to replace cement in construction. So let's take a quick look at the differences between these two building materials!
Lime and cement, common origins
Difficult to determine the exact origin of the use of lime in the building. However, according to historical studies, it has gone through more than 6,000 years of history and hundreds of civilizations to endure until our time. She has started to find renewed interest in environmentally friendly constructions in recent decades.
Coming from limestone deposits then heated to over 800 ° C, it is then combined with water to produce mortars, concrete and other coatings.
Cement, on the other hand, has appeared gradually over the years. Initially, it is a mixture of lime and powdered stones (equivalent to current formulated lime), then it evolved and gained momentum with the discoveries of Louis Vicat in the 19th century. Today, lime is only a minority component of an artificially created cement containing many additives.
Composition of lime and cements
Limes are composed, depending on the products and manufacturers, of varying amounts (for formulated lime) at 100% of pure lime, without additives for natural lime . Formulated lime can be combined with natural additives (such as hemp, wood, etc.) or chemicals (minerals, hardening agents, etc.). The fuel generally used for cooking is charcoal.
Cements, for their part, are generally composed of less than 2% lime and many mineral additives containing in particular aluminum, iron, silicon and sulphates. When cooking, tires or industrial wastes are generally used as fuel, adding heavy metals in significant amounts to the cement and the atmosphere.
The uses of lime and cement.
Lime has many uses:
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It can be used as a binder for construction materials (compatible with almost all construction materials).
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For the realization of screeds
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It can be used to make coatings including finishing.
Cement is mainly used for:
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The reinforced concrete
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Binder between porous cement-based construction materials (concrete block, etc.)
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Realized screeds
We have listed the main uses but we have possibly forgotten some less common uses, do not hesitate to add comments in the comments, we will edit the article.
Natural material versus artificial material
Lime
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Healthy material that does not release toxic substances over time
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Very good humidity regulation
Cement
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Materials containing heavy metals, sulphates and chlorides which are released throughout the life of the product
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Low humidity regulation
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Artificial material made from a mixture of residues from other industries.
Thatched roofs (wheat straw, rye straw, buckwheat straw, reed, rush, heather or broom) are biodegradable and insulating. A thatched roof requires a slope of 35-40° so that rainwater is well evacuated.