Flashcards in C2b Deck (16):
What rocks are used in construction of buildings and roads?
Granite, limestone, marble and aggregates.
Relates some construction materials to the substances found in the Earth's crust from which they are manufactured.
Aluminium and iron from ores.
Brick from clay.
Glass from sand.
Why are there environmental problems when rocks are quarried or mined from the ground?
Landscape is destroyed and has to be reconstructed when the mining or quarrying has finished, which costs money.
Transporting rocks can cause noise and pollution. The quarrying process produces dust and makes a lot of noise.
Put marble, granite and limestone in order of hardness.
Limestone, marble and granite.
Why do granite, marble and limestone have different hardness?
Limestone is a sedimentary rock, which is generally soft, marble is a metamorphic rock made by the action of high pressures and temperatures on limestone, and granite is an igneous rock, which is very hard.
What are limestone and marble both forms of?
What does limestone thermally decompose to make?
Calcium oxide and carbon dioxide.
What is the word equation for the decomposition of limestone?
Calcium carbonate - calcium oxide + carbon dioxide
What is the balanced symbol equation for the decomposition of limestone?
CaCO3 - CaO + CO2
What is thermal decomposition?
Reaction in which, when heated, one substance is chemically changed into at least two new substances.
How is concrete made?
Cement, sand, aggregate and water are mixed together. The mixture is then allowed to set.
When is cement made?
When limestone and clay are heated together.
How can concrete be reinforced using a steel support?
The steel support is made by joining steel bars or cables together. Then they are surrounded by a mould which concrete is poured into, to fill the gaps in the steel support, and sets hard.
What type of material is reinforced concrete and why?
A composite material because it's a combination of concrete and a solid steel support.
Why is reinforced concrete a better construction material than non-reinforced concrete?
It combines the hardness of concrete with the flexibility and the strength of the steel.
In an exam:
Buildings made of reinforced concrete will be able to flex more without collapsing because of the flexibility of the steel.
Both materials are very hard.
Steel is stronger than concrete so reinforced can hold a bigger load without breaking.