Silica fume is often used in beton og ildfaste materialer, and the main purpose is to use the very fine particles of silica fume to fill the pores between the particles of cement and other materials, thus making the concrete more dense. Most of the general particle size of cement is 3~30μm, how much finer is the silica fume than it?
The fineness of silica fume and its role
Silica røg, also known as silica fume, as a gray particle agglomerates, the fineness of its particles less than 1μm can account for more than 80%, the average particle size are 0.1μm to 0.3μm, its fineness is about 80 til 100 gange cementens. So when the concrete is mixed with silica fume, the silica fume particles can basically fill the pores between cement particles, cement hydrate and aggregate pores, og andre indbyrdes aggregerede porer, gør betonen mere tæt, dermed forbedre hårdheden af beton, uigennemtrængelighed og andre egenskaber.
I selve brugen af processen, finheden af silica-røg er ikke konstant, hovedsagelig fordi brugen af beton eller ildfaste produkter nogle gange ikke kræver en høj grad af kompakthed, selvom det kan kontrolleres ved at reducere mængden af silica-røg, men reduktionen i mængden af silica-røg kan få styrken af silica-dampen til at forbedre effekten er ikke indlysende. Så generelt i fremstillingen af beton eller ildfaste materialer, vil først vælge andet indhold, forskellig finhed af silica-røg, med forskellig indblanding i materialeprøverne til blandings- og hærdningsforsøg, to determine the material preparation of the choice of silica fume specifications.
The common fineness of silica fume specifications
| Specifications (mesh) | Sieve residue (finhed) |
| 500μm-180μm(30 mesh-80 mesh) | +500μm≤3%;-180μm≤10% |
| 425μm-150μm(40 mesh-100 mesh) | +425μm≤5%;-150μm≤15% |
| 250μm-140μm(60 mesh-110 mesh) | +250μm≤3%;-140μm≤10% |
| 125μm-74μm(120 mesh-200 mesh) | +125μm≤3%;-74μm≤10% |
| -74μm(-200 mesh) | +74μm≤5% |
| -45μm(325 mesh) | +45μm≤5% |
| 5μm-1μm(2500 mesh-12500 mesh) | +5μm≤5% |