Blending amount

Generally 5-10% della quantità di materiali cementizi.

The mixing method of silica fume is divided into internal mixing E external mixing.

1. Miscelazione interna: under the premise of the same amount of water, 1 parte dei fumi di silice può essere sostituita 3-5 parti di cemento (peso) e mantenere invariata la resistenza alla compressione del calcestruzzo migliorando al tempo stesso altre proprietà del calcestruzzo.
2. External mixing: the amount of cement remains unchanged, and the addition of silica fume significantly improves the strength of concrete and other properties. Calcestruzzo miscelato con fumi di silice quando si ha una certa perdita di lavorabilità. Questo punto deve essere notato nel test del rapporto.

Silica fume must be used in conjunction with water reducing agents, it is recommended to compound fly ash and finely ground slag to improve its constructability.

When formulating concrete with silica fume, the general weight ratio with cementitious materials is:

• calcestruzzo ad alte prestazioni: 5-10%.
• calcestruzzo idraulico: 5-10%
• Shotcrete: 5-10%.
• Pumping aid: 2-3%.
• wear-resistant industrial flooring: 6-8%.
• mortaio polimerico, insulation mortar: 10-15%.
• Indefinite refractory castables: 6-8%. Before use, please select the reasonable and economic mixing amount through experiment according to the actual needs.

Mixing method.

Silica fume concrete and castables should be made by the test room. Strictly follow the construction ratio. Silica fume should be added to the mixer immediately after the aggregates are fed. There are two procedures for adding.

1. Into the aggregate, seguito da fumi di silice, miscela secca di cemento, and then add water and other admixtures.
2. Mettere in aggregato grosso + 75% acqua + FUME DI SILICA + 50% aggregato fine, mix for 15-30 secondi, poi mettere il cemento + mescolanza + 50% aggregato fine + 25% acqua, mix until uniform. Il tempo di miscelazione è 20-25% O 50-60 secondi in più rispetto al calcestruzzo normale. Never add silica powder into the already mixed concrete.

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 vibrate densely during construction well. The early strength of silica fume concrete will make the final setting time earlier, which should be paid attention to when plastering; allo stesso tempo, the addition of silica fume will improve the viscosity of concrete and significantly reduce water secretion, making plastering slightly difficult.

Construction safety

Silica fume concrete construction safety should be strictly in accordance with the relevant national construction specifications for concrete projects, but because silica fume is light, it is strictly prohibited to throw the material from a height to prevent silica fume from flying.