Construction measures for lightweight gypsum mortar in winter

1. In the winter period, the brick masonry project adopts the method of adding chlorine-free salt antifreeze mortar.

2. Requirements for materials:

(1) Dust and snow on the surface of bricks should be cleaned before laying;

(2) Cement Ordinary Portland cement is used and cannot be frozen during use;

(3) Lime paste should be melted and remixed before use; lime paste that is dehydrated and weathered due to freezing cannot be used.

3. The consistency of masonry mortar in winter should be appropriately increased compared to normal temperature construction, which can be solved by adding lime paste. The consistency is controlled at 8~13cm.

4. The temperature of the mortar during use should not be lower than 5℃.

5. In order to mix the hot mortar, a special heating water tank is equipped. The temperature of the water is controlled at about 90°C. The water and sand are mixed first, and then the cement is added.

6. The temperature of the water should be checked frequently, no less than once an hour, and the thermometer should stay in the water for no less than 1 minute.

7. The time for mixing mortar in winter should be appropriately extended, generally 2 minutes longer than during normal temperature.

8. Measures to reduce the temperature loss of mortar during mixing, transportation and storage:

(1) The mixing of mortar should be carried out in an insulation shed, and the ambient temperature should not be lower than +5℃; winter construction mortar must be mixed and transported, and cannot be stored or transported twice.

(2) Shortening the mortar transportation distance is the main basis for setting up a mixing station. When transporting mortar by trolley, the vehicle body should be insulated. The car body is made of double-layer steel plates, and the middle is filled with wood saw foam.

(3) Mortar must be mixed and used immediately, and the storage time of mortar should not exceed 15 minutes.

(4) The transport vehicle should be cleaned in time and cleaned with hot water after get off work every day to avoid freezing.

9. Strictly use frozen mortar.

10. The “three-one bricklaying method” is used for laying bricks, that is, one shovel of ash, one brick, and one squeeze.

11. Before laying bricks, a number of rods must be erected. The average thickness of horizontal and vertical mortar joints must not be greater than 10mm. The thickness and uniformity of mortar joints must be checked frequently during construction.

12. Before the end of work every day, the surface of the masonry shall not be spread with mortar, and the surface of the masonry shall be covered with straw curtains. When you go to work the next day, you should first sweep away the frost and snow on the surface of the bricks before continuing with the masonry work.

13. For the amount of antifreeze in the mortar, refer to the experimental report and the manufacturer’s material instructions.

14. How to mix antifreeze: The antifreeze should be dissolved in water first, and then put into stirring.

15. When the lowest temperature of the day is ≤ -15°C, the mortar strength should be increased by one level according to the normal temperature construction.

16. When ordinary bricks are laid under positive temperature conditions, the bricks should be properly watered and moistened, and a watering can can be used to pour and lay them. When laying bricks at negative temperatures, the bricks are not watered, but the lime, sand, ice and snow on the surface of the bricks must be removed. </p