Nonmetallic Construction Materials

materials of mineral origin used in construction in their natural state, without the separation of any individual minerals from them. Among the nonmetallic construction materials are fillers for concrete and asphalt concrete, wall stones and blocks, facing pieces, road-building materials, and mineral powders.

Nonmetallic construction materials are produced by mechanical treatment of igneous, sedimentary, and metamorphic rocks, which are mined almost exclusively in quarries. The main treatment processes are sorting (for sand and gravel); crushing and sorting (for production of crushed stone, quarrystone, and crushed sand); classification (for production of graded sand); washing of crushed stone, gravel, and sand and sometimes their

dry cleaning; sawing, framing, buffing, and polishing (in the production of facing slabs from semifinished blocks); and drying and pulverizing (for the production of mineral powders).

The specifications that apply to nonmetallic construction materials relate mainly to grading, content of powdery and clayey particles and weak or weathered rock, strength, frost-resistance, sometimes grain shape, type of rock, and content of harmful impurities; wall stones and facing slabs must also satisfy requirements for linear dimensions and tolerances, as well as requirements regarding the face texture.