Construction preparation
2.1 Materials and main machines:
2.1.1 Bricks: The variety and strength level of bricks must meet the design requirements and the specifications should be consistent. There are factory certificates and test sheets.
2.1.2 Cement: Generally, No. 325 slag Portland cement and ordinary Portland cement are used.
2.1.3 Sand: medium sand, which should pass through a 5mm aperture sieve. When preparing mortars below M 5, the mud content of the sand should not exceed 10%; for mortars of M5 and above, the mud content of the sand should not exceed 5% and must not contain grass roots and other debris.
2.1.4 Admixtures; lime paste, fly ash and finely ground quicklime powder, etc. The slaking time of quicklime powder shall not be less than 7 days.
2.1.5 Other materials: tie bars, embedded parts, waterproof powder, etc.
2.1.6 Main equipment: mortar mixer, shovel, planer adze, support board, line weight, steel tape measure, ash trough, small bucket, brick clamp, small wire, sieve, broom , Eight-shaped ruler board, steel bar clips, iron trowel, etc.
2.2 Operating conditions:
2.2.1 Foundation trench: The concrete or lime soil foundation has been completed, and the hidden inspection procedures have been completed.
2.2.2 The basic axis and edge lines have been placed; tare poles have been erected (generally 15 to 20m apart, and should be set up at corners), and pre-inspection procedures have been completed.
2.2.3 According to the bottom elevation of the bottom layer of bricks on the scale rod, use a cable to check the surface elevation of the foundation cushion. If the horizontal mortar joints of the first layer of bricks are greater than 20mm, fine stone concrete should be used first. For leveling, it is strictly forbidden to mix fine stones into the masonry mortar or use mortar to level it, and it is not allowed to cut bricks for leveling.
2.2.4 During normal temperature construction, the clay bricks must be watered and moistened the day before they are laid. Generally, it is advisable for the water to immerse about 1.5cm from the four sides of the bricks.
2.2.5 The mortar mix ratio has been determined in the laboratory, and the mortar trial molds (6 pieces per set) are prepared on site.
Operating process
3.1 Process flow:
Mix the mortar → determine the assembly method → ??arrange the bricks and lay down the bottom → lay the bricks → apply the moisture-proof layer
3.2 Mixing mortar:
3.2.1 The mortar mix proportion should be based on weight ratio and determined by the laboratory. The cement measurement accuracy is ±2%, and the sand and admixtures are ±5%. .
3.2.2 It is advisable to use mechanical mixing. The feeding sequence is sand → cement → admixture → water, and the mixing time shall not be less than 1.5 minutes.
3.2.3 Mortar should be mixed and used. Generally, cement mortar and cement mixed mortar must be used within 3 hours and 4 hours after mixing. Overnight mortar is not allowed to be used.
3.2.4 The foundation is based on one floor. For every 250m3 of masonry and various mortars, each mixer should make at least one set of test blocks (a set of six blocks). If the mortar strength grade or mix ratio is changed, Test blocks should also be made.
3.3 Determine the assembly method:
3.3.1 The assembly method should be correct, generally using full dings and full strips.
3.3.2 The "three-one" bricklaying method (that is, one shovel of ash, one brick, and one squeeze) is used for the joints between the upper and lower layers. It is strictly forbidden to use water to flush the mortar and grout the joints. .
3.4 Laying out the bricks and laying out the bottom:
3.4.1 The size and retracting method of the large foundation feet must comply with the design drawings. For example, one layer should be retracted at a time, both inside and outside. Tin bricks; if the second floor is set back, the first floor is made of strip bricks, and the second floor is made of nylon bricks.
3.4.2 At the corner where the legs are large, seven-quarter heads should be placed according to regulations. The number is three for a one-and-a-half-brick wall, four for a two-brick wall, and so on.
3.5 Masonry:
3.5.1 Before laying the brick foundation, the surface of the foundation cushion should be cleaned and moistened with water. The corner of the wall should be laid first, and the height of the corner should not exceed five layers of bricks each time. The corners should be leveled and hung straight as they are laid.
3.5.2 The foundation wall should be hung with wires, the 24mm wall should be hung with wires on the backhand, and the wall with 37mm and above should be hung with wires on both sides.
3.5.3 If the foundation elevation is inconsistent or there are locally deepened areas, the masonry should be built from the lowest point upwards. Frequent cable inspections should be made to keep the masonry smooth and straight and prevent "screw" walls from being built.
3.5.4 When the foundation is laid to the upper part of the foundation, wires must be pulled to check the axis and edge lines to ensure that the foundation wall is in the correct position. At the same time, the brick layer and elevation of the skin pole should also be compared. If there is any deviation, it should be gradually adjusted in the horizontal mortar joints to make the number of layers of the wall consistent with the skin pole.
3.5.5 The overhanging bricks of the heating ditch and the upper layer of laminated bricks should be built with D-bricks. The mortar joints must be tight and the elevation of the overhanging bricks must be correct.
3.5.6 All kinds of reserved holes, embedded parts, and tie bars should be left in accordance with the design requirements to avoid subsequent chipping and affecting the quality of the masonry.
3.5.7 The corners of the deformation joints should be built according to the right angle requirements. The walls built first should be scraped off the tongue ash; the walls built later can use shrinkage ash, and debris falling into the joints should be removed at any time. Clean up.
3.5.8 The model and elevation of the pipe trench and opening lintel must be correct, and the bottom ash must be full; if the ash is more than 20mm thick, use fine stone concrete to pave it, and the length of the wall at both ends should be the same.
3.6 Apply moisture-proof layer: Re-lay the movable bricks on the top of the wall, clean them, water them to moisten them, and then apply waterproof mortar. When there is no design specification, the general thickness is 15~20mm, and the amount of waterproof powder is 3% to 5% of cement weight.
3.7 Construction during the winter rain period:
3.7.1 The mortar should be mixed with ordinary Portland cement, and admixtures such as lime paste should have anti-freezing measures. If frozen, they must be melted Can be used later. The sand shall not contain frozen blocks larger than 10mm.
3.7.2 The bricks should be kept clear of frost and water should not be watered in winter. The consistency of the mortar should be appropriately increased.
3.7.3 Salt-mixed mortar is generally used for bricklaying, and the salt content and material heating temperature are all in accordance with the winter application plan. The temperature of mortar when used should not be lower than +5℃.
3.7.4 During construction during rainy periods, foundation trench filling and rainwater erosion of the mortar should be prevented; the consistency of the mortar should be appropriately reduced. The height of masonry construction should not exceed 1.2m per day, and the upper surface of the masonry should be covered when the work is completed.
Quality standards
4.1 Guarantee items:
4.1.1 The variety and strength level of bricks must meet the design requirements.
4.1.2 The mortar variety meets the design requirements, and the strength must meet the following regulations:
4.1.2.1 The average compressive strength value of each group of test blocks of the same variety and the same strength mortar is not less than Design strength value.
4.1.2.2 The minimum strength value of any group of test blocks shall not be less than 75% of the design strength.
4.1.3 The masonry mortar must be full and dense, and the mortar fullness of the horizontal mortar joints of solid brick masonry must be no less than 80%.
4.1.4 It is strictly forbidden to leave straight rafters at the corners of exterior walls. At other temporary interruptions, the practice of leaving straight rafters must comply