Gaseous silica, also known as white carbon black, is commonly referred to as fumed silica.Fumed silica is an amorphous powder substance obtained by the hydrolysis of chlorosilane in high-temperature water generated by a hydrogen oxygen flame. Fumed silica is an amorphous white powder, which is a non-toxic, odorless, and pollution-free inorganic nanomaterial. Fumed silica exhibits a three-dimensional network structure, with unsaturated bonds and hydroxyl groups in different bond states (isolated hydroxyl, ortho hydroxyl, double hydroxyl, etc.) on its surface.

Glass fiber reinforced concrete (GRC) is a high-performance cement-based composite material formed by embedding high elastic modulus glass fibers into the cement matrix. The cement matrix in GRC enables the glass fibers to maintain the required reinforcement position and direction, and transfers external loads between the glass fibers, greatly reducing the brittleness of the cement matrix. The excellent performance of GRC makes it have broad application prospects in fields such as architecture, civil engineering, agriculture, forestry, animal husbandry, and fishery.

The main components of GRC are ordinary Portland cement, white cement, low alkalinity sulphoaluminate cement, alkali resistant glass fiber chopped felt, acrylic acid copolymer lotion such as Forton VF-774, polycarboxylic acid water reducer, silica fume, fly ash and fumed silica.

The main modification direction of fiberglass reinforced concrete is to add mineral fine admixtures with high volcanic ash activity to cement, such as fly ash, silica fume, metakaolin, and nano silica (fumed silica); Add polymer lotion into cement, such as acrylic tool lotion "Forton" VF-774; The technological route in China is to use low alkalinity sulfoaluminate cement and alkali resistant glass fibers containing zirconium and titanium (containing 14.5% ZrO2 and 6% TiO2) or high zirconium alkali resistant glass fibers (containing more than ZrO216%) to configure GRC, which is known as the "double insurance" GRC technology route with Chinese characteristics.

GRC curtain wall

Fumed silica is mainly used in GRC for relatively high-end furniture products, and is less commonly used in ordinary GRC curtain walls. Its main functions include: reducing the alkalinity of cement by reacting with calcium hydroxide in cement to improve the durability of GRC products; The strength of GRC products is improved mainly due to the surface effect and small size effect of nanoparticles. When the particle size is reduced to the nanometer level, not only the number of surface atoms will increase rapidly, but also the surface area and surface energy of nanoparticles will increase rapidly. As a result, their chemical activity and catalytic activity have changed greatly compared with ordinary particles, resulting in a large amount of bonding between gas-phase silica and hydration products, and taking gas-phase silica as the crystal core, a hydrated calcium silicate gel phase will be formed on the particle surface, turning the loose hydrated calcium silicate gel into a network structure with fumed silica as the core, reducing the creep degree of cement stone, thus improving the Strength and other properties of cement hardened paste.