Concrete mix is a building material, obtained by mixing together definite proportion of fine aggregate, coarse aggregate, water, cement and additives

Additives, admixture may be added to the concrete in very small quantities to alter properties of the concrete mix.

Types of concrete mix

1. Plain/ mass concrete – not reinforced
2. Reinforced concrete – reinforced.
3. Pre-stressed concrete- pre-cast with reinforcement.

Advantages of concrete as a construction material.

1. It is used for a variety of purpose in construction e.g foundation, wall, roads, airfield, bridges, and water retaining structures. E.t.c ( its versatile )
2. It possess a high compressive strength and therefore allows construction of high rise building.
3. Is not affected to corrosive and weather affects.
4. It can be easily handled and moulded into shapes when it is still fresh /plastic.
5. It can be sprayed and filled into cracks for repair purposes.
6. It is economical in the long run as compared to other engineering materials
7. Form work can be re-used for a number of times for similar jobs which results to being economical.
8. In reinforced concrete, the concrete and steel have a very good combination because the coefficient of expansion of concrete and steel are nearly equal.
9. Frequent repairs are not needed for concrete structures
10. Concrete is fire resistance/proof material and continuous to become stronger with time and age.

Disadvantages of concrete 

1. It has a low tensile strength and therefore cracks easily hence requires to be reinforced.
2. It expands and contract with change in temperature therefore by creating internal stresses which may lead to cracking.
3. It is usually heavy in weight and hence may require special lifting equipment.
4. Concrete as a material develops creep under sustained load
5. Concrete is subjected to thermal movement during setting and hardening caused by heat of hydration of cement.

Properties of good concrete

1. It should be workable and especially in its plastic state. (wet state)
2. It should be strong enough to carry the load for which it is designed for.
3. It should be impermeable as well as durable.
4. It should be produced at a low cost