PTs for asbestos-cement products

Application of a portlandtsement of PTsA in production of asbestos-cement products is characterized by a number of features. At production of asbestos-cement products initial hydration of cement proceeds at very high water cement relation; in the course of production from strongly flooded asbestotsementiy weight a significant amount of water is filtered, sucked away and wrung out. Parts of cement have to be rather thin to keep on asbestos fibers; at the same time their excessive dispersion can cause the increased water requirement knitting, negatively reflected in dehydration and consolidation a product. In this regard the portlandtsement, in accordance with GOST 9835 — 77, has to have the grinding subtlety characterized by a specific surface not less than 2200 and no more than 3200 cm2/g.

Clinker for this cement has to contain (%): C3S of not less than 52, and SZA not less than 3 N no more than 8. The maintenance of Saoslob is allowed no more than 1, a MgO — to 5%.

For an intensification of a grinding of clinker introduction of the additives which are not worsening quality of cement in number of no more than 0,5% on the mass of cement is allowed. The beginning of a skhvatyvaniye of this cement has to come not earlier than 1,5 h, and the end — no later than 10 h from the beginning of a zatvoreniye.

The Portlandtsement for production of asbestos-cement products is divided into brands 400 and 500 defined on samples from solution 1: 3 in accordance with GOST 310.1 — 76 (with amendment) — GOST 310.4 — 81.

The Portlandtsement for production of asbestos-cement products is characterized practically by the same construction properties, as a usual portlandtsement, and differs from it in more intensive curing and growth of durability in initial terms.

Other goods: cement, slate, slag stones, plates, brick, electrodes, crushed stone.