Concrete

Definitions

(Noun) A mixture of cementious materials, aggregate and water which chemically reacts to form a solid

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(Noun) it's a mixture of sand, cement, gravel, and water. and sometimes steel and in this case called reinforced concrete.
there many types of concrete like: rapid hardening concrete, low temperature concrete, high strength concrete, high and low density concrete.

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(Adjective) The antonym of abstract