Hi Kendal. Thank you for your question.

Concrete refers to cement concrete which is obtained by mixing cement and aggregate, water and admixtures. It is an engineering composite material and is widely used in civil engineering.

Because the compressive strength of concrete is gradually hardened by cement cementation, and the increase of strength trend will be slow after 28 days, so 28d is regarded as the standard strength, which not only makes full use of concrete performance, but also prevents the construction progress from being affected by too long time to reach the standard.

Besides strength requirements, on the one hand, concrete should be able to resist various factors in the use process, such as freezing resistance, water penetration resistance, chloride ion permeation resistance, shrinkage, carbonization, steel corrosion, sulfate resistance, fatigue deformation resistance, alkali aggregate reaction, etc., which is collectively known as durability. The durability of concrete determines the life of concrete. On the other hand, the workability of concrete determines whether the composition of concrete mixture can be kept uniform, and whether it is convenient to pour and vibrate in production and operation. Therefore, the workability, which covers three properties of fluidity, cohesion and water retention, is an important performance of concrete mixtures.

The formation and development of concrete is not easy because of many factors and conditions. There are rich experiences absorbed in the practice. Perhaps it is because of this reason that concrete can bear the development of an era.

Liming Heavy Industry (Shanghai)