1, the amount of the content: the general 5-10%. Silica fume method consists of mixing and mixing,
Doped (1): in the premise of constant amount of water added, a silica fume can replace 3-5 portions of cement (W) and keep the compressive strength of concrete invariant and improve other properties of concrete.
(2) the same: the cement dosage is constant, the addition of silica fume significantly improves the strength and other properties of concrete. The addition of silica fume concrete with slump loss. This need to be noted in the mix ratio test.
With the use of silica fume and superplasticizer to be recommended, fly ash and slag to improve the construction of.
When concrete is prepared with silica fume, the weight ratio of the cementitious material is generally:
(a) high performance concrete: 5-10%;
(two) hydraulic concrete: 5-10%
(three) jet concrete: 5-10%;
(four) the pump aid: 2-3%;
(five) wear resistant industrial flooring: 6-8%;
(six) polymer mortar, thermal insulation mortar: 10-15%,
(seven) amorphous refractory casting material: 6-8%. Before use, according to the actual needs of the actual need to choose a reasonable, economic volume.
2, adding method:
Silica fume concrete and the pouring material should be made by the test chamber to make the construction mix ratio. Strictly in accordance with the proportion of the construction. In the mixing of silica fume concrete, the silica fume should be added immediately after the aggregate is cast. There are two procedures in the way:
(1) the aggregate, then put into the silica fume, cement dry mix, then add water and other additives.
(2) into the coarse aggregate +75% water + silica fume +50% fine aggregate, stirring 15-30 seconds, and then put into cement + admixture +50% fine aggregate +25% water, stirring until uniform. Mixing time longer than ordinary concrete 20-25% or 50-60 seconds. Should not be added in concrete mixing powder.
3, construction method:
There is no significant difference between the construction method of silica fume concrete and ordinary concrete, but it is necessary to organize and compacting the construction of the concrete. Silica fume concrete early strength performance will make the final setting time in advance, in plaster should pay attention to add; simultaneously adding silica fume will improve the viscosity of concrete and drastically reduce the bleeding and the plaster slightly difficult.
4, construction safety:
Silica fume concrete construction safety should be strictly in accordance with the concrete engineering of national construction standards for operations, but because of the silica fume is lighter, is strictly prohibited high spilled material, silica fume is prevented from flying.