What is the amount and method of determining the expansion agent?

  The determination of the amount of expansion agent is the same as the determination method of the general chemical admixture addition amount. It must be determined by the test method. The correct method for determining the amount of concrete expansion agent is according to the test method in GBJ50119 Technical Specification for Concrete Expansion Agent Application. Using the actual engineering raw materials, the limit expansion rate test shall be conducted so as to achieve the limit of the expansion agent and the expansion agent when the engineering design limits the expansion rate and the strength index.

In particular, it is necessary to point out that in some areas, based on the base content of a certain type of expansive agent, the amount of artificially defined expansive agent in concrete should not exceed 8%, which is unscientific. First of all, the current expansion agent standard stipulates that the alkali content of the expansion agent should not exceed 0.75%, and most of the products sold on the market are 0.3~0.6%, which is lower than the average cement. The expansion agent can be mixed with other methods, and only the concrete can be reduced. The total alkali content. Secondly, as a component material of concrete, expansion agent, like cement and other mineral admixtures (fly ash, silica fume, ground slag powder, etc.), the amount of expansion agent should be based on the design limit the expansion rate or self stress value, By trial and error, it is not possible to artificially limit the upper limit, otherwise some engineering sites such as self-stressing concrete and which require a large amount of expansion will cause project quality accidents due to insufficient expansion. In addition, the percentage content itself is also very limited. The concrete of strength grade C20 and the concrete of strength grade C60 are different due to the difference of the amount of gelling material, taking 8% blending as an example, the amount of expansion agent in C20 is less than 20kg/`m^ 3 `, and expansion agent in C60 will reach 40~50kg/`m^3`, there will be insufficient expansion of C20 concrete and C60 concrete expansion is too large.

Consult expansion agent dosage and determination method telephone or 18639913333.