Pretec AS was established in 1985 and manufactures, stocks and markets products for the construction industry. We supply a wide range of products for a variety of industries, but specialize in 2 areas. One segment is concrete industry, and the other contractors who work with rock support, as well as water- and frost protection in tunnels. This is our priority, and we have built up a wide range of products that are stocked in Norway. Within these segments, we always seek new and better solutions. This strengthens our position by contributing to increased value for our customers.
NC-Bolt M20 is a combination bolt. Material in this bolt is rebar Ø20/M20 with yield strength 500N/mm² and ductility min. 9%. NC-Bolt is approved by the Norwegian Road Authority for use in their tunnels. Other markets for this bolt is sub-sea tunnels, sewer tunnels, rail tunnels, and in mining. Benefits of the NC-Bolt M20: NC-Bolt M20 is mounted with expansion shell for temporary anchoring in the drilled hole. The bolt should be pre-tensioned to 50kN. Later the bolt is grouted through it’s head, and the plastic tube, for permanent installation. The bolt is thereby enveloped both inside and outside the grouting tube. The bolt itself is additionally coated with duplex system Pc-Coat™ which consists of hot dip galvanizing, followed by zinc manganese phosphate, and finally epoxy powder coating. This provides particularly long life expectancy of the NC-Bolt. Spherical bearing plate can adapt to 35° angular offset against rock wall. NC-Bolt M20 is installed in drill hole 45/48 mm. Pretec AS delivers its bolts professionally packaged on pallet with a view to further work on the project. Expansion shell is also mounted on bolts, from our factory.
The Pc-Bolt is a combination bolt. It is used where uncertainty regarding rock quality makes it necessary to use bolts with special mechanical properties. The material in the Pc-Bolt is Ø26x5mm pipe with yield strength 500N/mm² and ductility min. 8%. This satisfies all mechanical properties that are relevant to the bolt. Pc-Bolt has got the same tension area all over its length. Especially the ductility and the grouting performance is highlighted. Our tests done on site in tunnels, and also references from customers in ongoing projects give us great praise for our efforts. Pc-Bolt is approved by the Norwegian Road Authority and also by Norwegian Rail Road Authority for use in their tunnels.
The Pc-Bolt will be inserted into the drilled rock hole, and mounted with an expansion shell for temporary anchorage. Later, the bolt is grouted to achieve permanent installation. The Pc-Bolt is partially ridged; this is to achieve better anchoring and adhesion, delaying and minimizing slippages if minor movements in the surrounding rock should occur. This, combined with the great ductility of the material, gives the Pc-Bolt extreme benefits compared to other solutions.
Another great advantage is how the bolt is grouted after it has been mounted in the drilled hole. Pc-Bolt is to be grouted trough the inside of the bolt. The bolt is filled from the inside and then start to fill up the drilled hole from the bottom and out to the spherical washer. This means 100% grout filling of the bolt and the drilled hole, every time. The bolt will be completely and permanently embedded in grout. Pc-Bolt has of course also Pc-Coat™ duplex system corrosion protection.