In the United States, a standard dump truck has one front steering axle, and one or two rear axles which typically have dual wheels on each side. Tandem rear axles are virtually always powered in the U.S., far less often in Europe.
A silicate is a compound containing an anionic silicon compound. The great majority of silicates are oxides, but hexafluorosilicate ([SiF 6 ] 2â) and other anions are also included. Orthosilicate  is the anion SiO 4 4â or its compounds.Related to orthosilicate are families of anions (and their compounds) with the formula [SiO 2+n ] 2nâ .he great majority of silicates are oxides, but hexafluorosilicate ([SiF 6 ] 2â) and other anions are also included.  Orthosilicate  is the anion SiO 4 4â or its compounds. Related to orthosilicate are families of anions (and their compounds) with the formula [SiO 2+n ] 2nâ .
Noun. 1. silica-a white or colorless vitreous insoluble solid (SiO2); various forms occur widely in the earth's crust as quartz or cristobalite or tridymite or lechatelierite. silicon dioxide, silicon oxide.cristobalite-a white mineral consisting of silica; found in volcanic rocks.ilicon dioxide, SiO 2, a compound that occurs widely in rocks and mineral forms, such as quartz, sand, and flint, and is used to make glass, concrete, and other materials.