1. Precipitated silica is an amorphous form of silica (silicon dioxide, SiO2); it is a white, powdery material.

2. Particularly, the polymer emulsion contains an amine-based strength accelerator and a polymer surfactant, and the high-strength quick-setting additive contains precipitated silica.

3. Silicon dioxide is an amorphous substance, which is produced synthetically by either a vapour-phase hydrolysis process, yielding fumed silica, or by a wet process, yielding precipitated silica, silica gel, or hydrous silica.