Raw materials - Some raw materials are found in the Earth's crust, whcih are used to make construction materials.
Rock hardness -
Sedimentary rock - Made from compressed and cemented together soft sediments. (limestone)
Metamophic rock - Formed when limestone is changed by heat and pressure. Typically composed of interlocking carbonate crystals. (marble)
Igneous rock - Formed when magma cools and solidifies. Interlocking crystals, very hard. (granite)
Thermal decomposition - Reaction when one substance breaks down when heated to give at least two new substances.
Calcium carbonate thermally decomposes when heated: calcium carbonate makes calcium oxide + carbon dioxideCement is made when limestone is heated with clay. Concrete is made by mixing cement, sand and small stones with water.
Reinforced concrete - Composite material which has steel rods or mesh running through it to make it a better construction material. The composite can still distinguish at least two materials.
Reinforced concrete is used in buildings because it is more flexible and unlike concrete, will not crack under tension.
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