In recent years, a new concrete technology is rapidly developing and applied to many practical projects, that is, high-performance concrete. High performance concrete takes durability as the main index of design, and has different requirements for durability, constructability, applicability, strength, volume stability and economy for different purposes.
Its configuration feature is low water binder ratio, and the selected materials must be mixed with enough fine mineral admixtures and additives in addition to cement, water and aggregate.
The addition of high-quality mineral fine admixture in concrete increases its compactness, reduces the capillary gap of concrete, improves the weak interface and microstructure between aggregate and cement colloid, increases the workability of concrete, prevents a large number of harmful substances from invading into the concrete, and reduces the conditions for concrete erosion.
According to the scientific experiment, the cost of adding appropriate proportion of fine mineral powder admixture is limited. In particular, the cost of C30 concrete with fly ash and mineral powder mixed with 20% fly ash and 20% ground fine mineral powder is basically the same as that of the original ordinary concrete. Concrete enterprises can create more wealth with lower cost.
The fine mineral admixture of high-performance concrete is mainly composed of fly ash and mineral powder in proportion. Fly ash shall be of stable quality. For reinforced concrete with strength grade not greater than C50, it is better to use national standard Grade I or Grade II fly ash, but the loss on ignition of fly ash shall be controlled to be less than or equal to 5.0%, and the fineness shall be controlled to be less than or equal to 20%.
For prestressed concrete with strength grade not less than C50, it is better to use national standard I fly ash, but the loss on ignition of fly ash should be controlled to be less than or equal to 53.0%. The mineral powder shall be the grinding product of water quenched slag, and the specific surface area of the mineral powder shall be 350-500m ²/ Kg, 28d activity index is greater than or equal to 95%, loss on ignition is less than or equal to 3.0%, and water content is less than or equal to 1.0%.
SMMVIK Machinery is a well-known supplier of grinding system integration, which can become a strong backing for the concrete industry. In order to improve the performance of concrete and achieve energy conservation to a large extent, a large vertical mill is introduced. This large vertical mill has large grinding capacity, low power consumption, excellent quality of mineral powder produced, and its activity index reaches about 100% in 7 days.
More importantly, the large vertical mill can grind the fly ash while processing the slag, which truly realizes the dual use of one machine and greatly saves the customer's equipment investment and later maintenance costs. The large vertical mill of SMMVIK Machinery has been applied in many projects, creating great value for customers.
