Monitoring the effect of quartz-sand replacement by amorphous-silica raw material on the microstructure of calcium silicate composites

Monitoring the effect of quartz-sand replacement by amorphous-silica raw material on the microstructure of calcium silicate composites

WoS Article

Quartz sand is the main raw material for the production, of autoclaved calcium silicate composites. However, its resources are rapidly dwindling, and alternative siliceous raw materials need to be sought and tested for replacement. Most often they are raw materials containing amorphous silica. Amorphous silica is more readily soluble than crystalline silica, and thus may contribute to the formation of a superior microstructure of the calcium silicate composite through calcium hydrate phases. This paper is focused on determining the optimal replacement rate of amorphous silica raw material for crystalline silica sand, while describing changes in microstructure of calcium silicate composites. The replacement rate was graded to 0%, 25%, 50%, 75% and 100%. Hydrothermal treatment conditions are based on the real production of autoclaved aerated concrete, so a temperature of 190°C and an isothermal holding time of 7 hours was chosen. To study the effect of the ratio of raw materials on microstructure, X-ray diffraction analysis supported by scanning electron microscopy images was used.

Quartz sand is the main raw material for the production, of autoclaved calcium silicate composites. However, its resources are rapidly dwindling, and alternative siliceous raw materials need to be sought and tested for replacement. Most often they are raw materials containing amorphous silica. Amorphous silica is more readily soluble than crystalline silica, and thus may contribute to the formation of a superior microstructure of the calcium silicate composite through calcium hydrate phases. This paper is focused on determining the optimal replacement rate of amorphous silica raw material for crystalline silica sand, while describing changes in microstructure of calcium silicate composites. The replacement rate was graded to 0%, 25%, 50%, 75% and 100%. Hydrothermal treatment conditions are based on the real production of autoclaved aerated concrete, so a temperature of 190°C and an isothermal holding time of 7 hours was chosen. To study the effect of the ratio of raw materials on microstructure, X-ray diffraction analysis supported by scanning electron microscopy images was used.

Calcium silicate compozite, glass, tobermorite

Calcium silicate compozite, glass, tobermorite

HÚŠŤAVOVÁ, J.; ČERNÝ, V.; DROCHYTKA, R.

2021

17.02.2020

Inštitut za kovinske materiale in technologije

Ljubljana

1580-2949

Materiali in Tehnologije

54

1

Republic of Slovenia

129

134

6

http://mit.imt.si/izvodi/mit201/hustatova.pdf