1. Concrete: It is an artificial composite solid material made of cementitious material, coarse aggregate (also known as aggregate) mixed with water and hardened after a certain time. It is the world's largest amount of artificial building material.
2. Common categories:
-- Classified by cementing materials:
Cement concrete, gypsum concrete, asphalt concrete, sodium silicate concrete, alkali slag concrete, polymer concrete.
-- Classification of concrete by function and use:
Such as structural concrete, waterproof concrete, heat resistant concrete, acid resistant concrete, fiber concrete and polymer concrete
Cement concrete is one of the most commonly used concrete, referred to as concrete, it is made of cement, coarse aggregate, fine aggregate, water according to the appropriate proportion of mixing and pouring hardening molding. Before hardening it is called concrete mix.

First, as one of the main building materials, concrete is rich in raw materials, durable, energy saving, and cheaper than metal, wood and plastic.

Ii. Other Advantages:
1, as needed preparation; 2, due to the need to shape;

▲ What are the properties of concrete mixtures required in engineering construction?
(1) fluidity, easy to pour and fill the mold;
(2) uniformity, aggregate distributed evenly in cement slurry, cement particles distributed evenly in water;
(3) Water retention, water does not bleed, segregation;

▲ Signs of good performance:
(1) It is not easy to separate into layers during transportation
(2) It is easy to tamp or self-compacting when watering
(3) The surface is easy to correct after forming

▲ Meaning of workability
Workability refers to the concrete mixture under certain construction conditions, easy to operate and can obtain the quality of uniform and dense concrete performance. Concrete with good workability should have good fluidity and be difficult to produce segregation or bleeding phenomenon in the construction operation process.
Workability is a comprehensive index, including fluidity, cohesiveness and water retention
(1) Fluidity: reflects the flow performance of concrete mix under the action of dead weight or vibration of construction machinery, and depends on the consistency of the mix
(2) cohesion: reflects the concrete mix of segregation resistance, stratification performance
(3) Water retention: refers to the ability of concrete mix to keep water and not easy to precipitate

(2) Workability test (liquidity test)
1) Slump test
2) Veb consistency test
3) Other methods