Concrete admixtures in part, although the content rarely, but play their own role. However, it was thrusting it and cement admixture "entangled" together, was "misunderstanding" must be a reason, though many of my friends all know that this is actually two different things, but today still look to science for admixture washed.

Ding Ding, d is the d

Concrete admixtures

Cementitious materials generally refers to the incorporation during the preparation of concrete, Portland cement and ordinary Portland cement or cementitious material is composed, silicon, aluminum, calcium and one or more oxides as main components , in concrete can replace part of the cement, having a predetermined fineness and condensation performance can be improved rigid powder material having pozzolanic activity or potential water fresh concrete workability and strength of concrete, its content is generally not less than cementitious materials 5% of the amount, and its main role is to improve the concrete workability, stability, durability and corrosion resistance.

Cement admixture

In the cement production process, in order to improve certain properties of cement, cement grade and increased production adjustment added to the cement and minerals in the material, known as cement mixing material, referred to as cement admixture. Depending on the nature of the material can be divided into two non-active and active mixed material mixed material. Adding the mixed material can be adjusted in cement and cement grade varieties, increase cement production, reduce production costs; to some extent, improve certain properties of cement, construction projects meet the special technical requirements of cement; comprehensive utilization of large quantities of industrial waste significance of environmentally friendly and energy saving.

Are common ground "to blame."

Although the cement admixture and concrete admixtures intersection, concrete admixtures can theoretically do admixture of cement, but cement admixture even active mixed material but not a substitute for concrete admixture, which is exactly what causes it?

    (1) From an engineering practice, concrete admixtures generally have some potential activity that plays ash effect, shape effect, micro-aggregate effect and interface effect, it can replace 10% to 50% of conventional Portland cement .
    (2) concrete admixture may also act as filling effect in the concrete, the regulating concrete or mortar strength grade.
    (3) concrete admixtures fineness ratio fineness cement admixture should be fine. Concrete Admixtures generally 400 ~ 450O / kg and above, even higher specific surface area, such as (silica fume); cement admixture is usually due to the grinding together with cement clinker, gypsum, its specific surface area is generally 330 to 380 m / kg or so, the fineness relatively thicker.
    (4) At present, there are mature concrete admixture GB or row label, but only raw cement admixture cement grinding time. From the concrete material system, the cement admixture can not replace concrete admixtures.
    The basic theory (5) shows that concrete, concrete admixtures is the sixth essential components of contemporary high-performance concrete.

So important, how to make good use of admixtures? In fact, it points to what admixtures.

Admixtures also diverse species

Concrete admixture of different varieties, usage and effects naturally differ. How to change the properties of concrete admixture good understanding admixture is critical.

Fly

When fly ash as concrete admixture in the same water-cement ratio, fly ash content not exceeding 20%, little effect on the properties of concrete, but a slight decrease in temperature of concrete. Only content exceeds 25%, the performance of fly ash concrete would have significantly improved.

Ground slag

Slag grinding the more detailed, the higher the activity, after the incorporation of concrete, hydration heat generated early, the more is not conducive to reduce the temperature rise of concrete. When the specific surface area exceeds 400 square meters of slag / kg, the low water-cement ratio for concrete (less than 0.30) when early strength concrete autogenous shrinkage increases with dosage increases.

Silica fume

After the incorporation of silica fume concrete, with the silica fume content and increased water demand increases, since the shrinkage also increases. Thus, the general content of the silica fume control between 5% to 10% is appropriate, and with the superplasticizer to adjust the water demand.

Mineral Fine Admixture

After the incorporation of mineral fines concrete is a very good cohesion, improve the workability of fresh concrete; after incorporation of mineral fine powder, as a corresponding reduction of cement clinker, the total amount of cement hydration heat will be reduced, which can reduce the temperature rise of concrete; you can adjust the strength development of concrete, and can improve the resistance of concrete to chemical attack, and enhance the durability of concrete.

Sisiyuan Conclusion
About admixtures, as long as the concrete mixed well, I Ye Hao good it!