Winter construction: masonry and installation of reinforced concrete at minus temperatures

Krympress reports:

The construction does not stop in winter, but the cold makes the work less predictable: the water in solutions and concrete freezes, the clutch falls, metal and concrete are “played” from temperature changes. Below are practical rules that help the masonry and installation of reinforced concrete at the minus.

Temperature thresholds and general approach

• Masonry: Use winter solutions or adhesives with anti -gun additives and conduct work in the temperature range indicated by the manufacturer (usually up to −10 … −15 ° C, for individual compositions — lower).
• Concrete/solution should not freeze before a set of critical early strength. This is achieved either by heating and shelter, or warmed up (electric cables of PNSV, induction/formwork heating), or a combination.
• Ice, hoarfrost, snow — enemies of adhesion. Supports, beds, grooves and reinforcement should be dry and clean.

Masonry of blocks and brick in winter

Materials and mixture

• Use certified winter solutions/adhesives or additives without calcium chloride (non -chloride — safer for reinforcement and embedded).
• Serve the components with warm ones: water 30-60 ° C, sand and blocks — heated/thawed. Do not overheat (the solution will grasp too fast).

Base and elements

• Small the snow, remove ice/hooks from armored rods, plates, walls. If necessary, heat the base with a heat gun and cover until the masonry starts.
• Aerated concrete/Ceramic blocks before laying hold in a warm warehouse/heating. Cold block «suck» heat from the seam.

Switch maintenance

• For aerated concrete — thin -haired winter adhesives; For brick — warm solutions with additives. Thickness and consumption — according to the technical card.
• Cover each tier: tents, insulation mats, PE film with ventilation gaps (so as not to accumulate condensate).

Control

• Control the air temperature in the work area and the temperature of the mixture at the output.
• Make control samples (cubes/»bagels») or use thermometers/sensors in critical documentation nodes.

3) installation of reinforced concrete (plates, beams, jumpers) at the minus

Preparation

• The supporting surfaces of the walls and crossbars are dry, without ice. Do not allow the «snow pillow» under the stove.
• The bed layer (solution/glue) — winter, warm, is laid immediately before installation.

Stropovka and rise

• Inspect the slings and traverses: without icing, normal rope flexibility/sling. Work strictly according to the passport of the crane (restrictions on the wind/temperature).
• The plate before laying is cleaned of snow/ice, voids — not clogged with snow.

After laying

• Fill the seams and joints with a warm winter solution, cover until a set of early strength.
• A survey/welding nodes — dry, welding work is not carried out on icing metal.
• For monolithic dobctions/stiffness diaphragms — see the concrete section below.

4) winter concreting of monolithic nodes and seams

Methods to provide heat

1. Warming without active heating — for small volumes and “warm” compositions: warm concrete, shelter with mats/PE+mineral wool, heat.
2. Active warming up:
   • PNSV/TPG — cable in the body of concrete, transformer;
   • Formwork heating — heating shields/sheets;
   • Infrared/air heating inside the heat.

Mixtures and additives

• Order winter concrete mixtures at the RBU (mobility, aggregate size, additives — according to TK).
• Use non -chloride anti -control additives (for assemblies with reinforcement/embedded).
• The goal is to maintain the temperature above zero before the set of critical strength (according to the project: usually 30–70 % of the calculated depending on the purpose of the node).

Control and documentation

• Thermomonitoring (thermocouple/loggers), a heating magazine (turning on/off, target temperatures).
• Removal of heating/shelters — after reaching a given strength; Do not allow harsh «thermalists».

5) organization, logistics and security

• Storing: materials — under a canopy, on pallets, with gaskets; Keep salt reagents away from the metal.
• Technique route: clearing, sprinkling, normal crane.
• Schedule: take out “wet” processes in the middle of the day, when warmer; At night — shelter.
• Labor protection: non -slip shoes, height insurance, heating of the trailer, recreation regulations brigades.

Result

Winter work is possible and safe if three conditions are observed:
Warm and suitable mixtures, freezing protection to a set of strength, clean and dry supports/joints. Add competent heating and documentation — and minus temperatures will cease to be a risk factor for quality and deadlines.

Source: https://megapolis-market.ru/

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