I. Material performance requirements
1, aerated concrete
(1) The model, specification, bulk density grade, strength, thermal conductivity and fire-resistant time grade of lightweight aerated concrete block must meet the design requirements, and the allowable deviation of block size and appearance quality should comply with the provisions of product qualification standards, with product factory certificate.
(2) The product age of lightweight aerated concrete block should exceed 28d, and the strength grade of the block should not be lower than A3.5.
(3) Block masonry must use a special binder that matches the block material, and have the product factory certificate. After masonry comes into play, witness sampling and reinspection. It can only be used after inspection.
2. Mortars
(1) The special mortar suitable for the characteristics of wall materials is a mortar with strong adhesion and excellent construction operation performance, which is suitable for dry construction. The performance indicators and requirements of mortar are shown in the table below.
Note: The main technical performance indicators of special mortar are that the bond strength is 50% higher than the national industry standard, and the delamination degree is better than the national industry standard.
(2) In order to ensure the sufficient bond strength of the special mortar for masonry, the cement dosage of the special mortar for masonry should not be less than 175kg/m3, which is verified by experiments and engineering practice.
(3) Masonry mortar or plastering mortar for non-load-bearing block walls can be divided into three grades: M5(Mb5), M7.5(Mb7.5) and M 10(Mb 10), and their varieties and strength grades should meet the design requirements.
3. Other materials
(1) The steel of Rachel steel bar, steel mesh and connecting steel plate shall meet the design requirements and the relevant regulations of construction steel.
(2) The Rachel steel bars buried in the mortar joint shall be cold-rolled ribbed steel mesh, and hot-dip galvanized, with the thickness of galvanized not less than 15μm or the weight of galvanized layer not less than 100g/m2. The diameter of cold-rolled ribbed bar should be 3.5 ~ 5.0 mm
(3) The special mortar used for plastering layer or crack-resistant part of external wall should be mixed with polyethylene single-bundle high-strength short fiber with good dispersibility, and the dosage of polyethylene fiber per cubic meter of mortar is 1.0kg, and its specification is12 ~19 mm.
(4) The mesh number of steel wire mesh used in plastering layer or crack-resistant part shall be 20mm×20mm, and the diameter of steel wire shall be1mm.. And it is recommended to use hot dip galvanizing.
(5) Anchors (such as nylon anchors, etc.). ) Test data shall be available for fixing door and window frames and hanging objects, indicating the pull-out force and shear force in the masonry used. Otherwise, it should be tested before selection and provide data to the design unit.
(6) PU foaming caulking agent used for joints between wall holes and doors and windows shall meet the requirements of relevant technical standards.
(7) The elastic sealing material used for caulking the external wall control joint should be a polymer sealing material with good weather resistance and durability and no pollution defects, and high-performance one-component polyurethane sealant should be used for caulking.
Second, the main machines and equipment
Portable masonry saw, portable electric mixer, tile knife, spatula, rubber hammer, spirit level, sanding board, brush, measuring rod, nylon thread, red pencil, crowbar, mixing bucket, mortar bucket, hammer, chisel, etc.
Third, the operating conditions
1. The main body of concrete structure has been completed and accepted.
2, determine the floor elevation, pop-up wall axis, edge, door and window hole line, after review, the preview formalities.
3. Blocks and special masonry binders have passed the quality acceptance and meet the requirements of design and product grade standards.
4, the operation team must go through the block construction technical training, technical disclosure before construction.
Fourth, the masonry technology
Pouring concrete guide wall → masonry preparation → mixing materials → block masonry → top joint sealing → inspection and repair.
Key points of verb (abbreviation of verb) construction
1, masonry preparation
Before laying, after the structural experience is accepted, the laitance residue on the ground of the grass-roots building will be cleaned up, and the grass-roots level will be leveled with C20 fine stone concrete or 1: 3 cement mortar, and the center line, sideline, door and window opening of the wall will pop up according to the design requirements.
2, elevation control points
The horizontal elevation control points should be laid out, and a number of leather poles should be set up to pull the leveling route. Set up the skin pole, handle the wall lacing, and prepare the masonry tools.
Step 3 mix materials
(1) Mixing binder: according to the ratio of adding 4 ~ 4.5 kg of clean water to 20kg of binder dry powder, put the mixture into a special bucket, stir it with a portable electric mixer, and mix the binder into cement. The mixing amount should be used up within 4 hours, and it must be stirred again after 30 minutes.
(2) The local cement mortar used when building lightweight sand aerated concrete blocks should be mixed with it.
4, block masonry
(1) First wet the base surface (guide wall) with water, and then spread the first skin block with 1:3 cement mortar. The vertical seam on the side of the block should be paved with adhesive, and the levelness and verticality of the block should be corrected with a spirit level and a rubber hammer. When laying, try to arrange blocks in advance, and the whole block is preferred. When the wood block needs to be disconnected, the length of the sawed wood block should not be less than 1/3 of the total length of the wood block. Blocks with a length less than 150mm shall not be used for block arrangement.
(2) The second skin block is initially laid with special adhesive, and it can be carried out only after the horizontal mortar joint of the first skin block is solidified. Corner and T-junction of block wall shall be laid vertically and horizontally.
During masonry construction, before each skin block is laid, clean up the floating sand (dust) on the surface of the block with a brush, and then brush adhesive and mixed mortar at the horizontal and vertical mortar joints after cleaning up.
When building with adhesive, use a special spoon to evenly spread the adhesive on the surface of the lower skin block. The vertical mortar joint can be laid on the end face of the block first, and then tapped with a rubber hammer after the block is on the wall. The rubber hammer should be struck inward from the top of the block first, and then compacted horizontally, so that the adhesive overflows from the mortar joint, and the mortar joint cannot have gaps, and the fullness is not less than 80%. Spilled glue should be removed in time, so that it can be easily built.
(3) Before each skin is laid, check the smoothness of the surface of the lower skin block (slurry laying surface) with a guide rule. After the unevenness is smoothed with a sanding board, it is cleaned with a brush, and then the horizontal and vertical joints are coated with adhesive.
(4) Use special adhesive for construction, and do not water wet the block when laying.
(5) The horizontal mortar joint of the block should be evenly daubed on the upper surface of the lower skin block with a spatula, and the vertical mortar joint of the block can be daubed on the side of the block with adhesive first, then spread on the wall, and then tap the block with a rubber hammer. It is required that the mortar joint is full and seamless, and the extruded binder should be removed in time. The thickness of mortar joint is controlled at 2 ~ 4 mm
(6) When laying each skin block, it is advisable to use a level gauge and a rubber hammer to correct the horizontal and vertical positions of the blocks, and make the upper and lower skin blocks overlap alternately. The overlapping length is generally not less than 1/3 of the overlapping block length, and not less than 100 mm ... Masonry should be laid layer by layer, and no seams should be left.
(7) Rachel between the block and the reinforced concrete column or wall: 2φ6 steel bars are set every 2 skins (50~80mm). First, an inverted isosceles triangular groove with a groove width (wall thickness of -40mm) and a groove depth of 50-80mm is dug on the block surface of the corresponding Rachel layer (the groove length is suitable for the length of Rachel steel bars), and the steel bars are tied with the built-in column and wall, and m/kloc cement mortar is used.
(8) Masonry corner and handover parts shall be laid at the same time. For temporary breaks that cannot be paved but must be left, they should be paved as oblique rubs. When rubbing, clean the rubbing mouth first, and then apply adhesive to build by laying bricks or stones.
(9) When the wall is > 4m in height and > 5m in length, a long horizontal reinforcement belt connected with the constructional column and the wall should be added in the middle of the wall. First, in the middle of the horizontal mortar joint of the block, the excavation section is an inverted triangular groove along the wall, with a width (wall thickness -40mm) and a depth of 80mm, in which 2φl0 long steel bars and φ6@300 distribution bars are placed, and they are poured with M 10 cement mortar to the top of the mouth.
(10) wall lintel: special lintel matched with aerated concrete block shall be adopted for the openings of doors and windows, and its width shall be the same as that of masonry. Both ends of the lintel should extend into the wall not less than 250㎜. When the width of the hole is more than 2m, reinforced concrete frames should be set on both sides of the hole. During installation, the mortar should be full and firmly combined.
(1 1) Top joint caulking: In order to ensure that the masonry at the top of the infilled wall is closely attached to the beam or slab, wedge masonry is adopted.
(12) inspection and repair: after the wall is laid, the surface flatness must be checked. If there is a small amount of deviation, it can be smoothed by steel tooth grinding plate and grinding plate, and the deviation value can be controlled within the allowable range.
(13) Connection between walls and doors and windows: concrete blocks containing anti-corrosion wooden bricks are laid in the upper, middle and lower positions on the walls on both sides of the door opening in C 15, and the wooden door frames are fixedly connected with the concrete blocks with nails. Plastic steel and aluminum alloy doors and windows are fixed with plastic expansion bolts or nails, and the iron parts of doors and windows are connected with concrete blocks. The gap between doors and windows and the wall should be filled with PU foaming agent.
The windowsill should be a reinforced concrete windowsill beam with both ends extending into the wall for 600 ㎜; 3φ6.0 longitudinal reinforcement should be placed at the bottom of a skin block under the window, with both ends extending into the wall for at least 700mm.
5, electrical pipeline, box laying
1) The laying of electrical pipelines and boxes can only be carried out after the wall masonry is completed and reaches a certain strength. Firstly, according to the design position, pop up the slot and opening position of pipeline and box on the wall, and slot with portable electric cutting machine and manual slotting device. Trough depth: the vertical seam should not be greater than 1/3 wall thickness, and the horizontal seam should not be greater than 1/4 wall thickness; The size of the box hole should be slightly larger than the external size of the box.
2) After the box hole is picked, clean it up, moisten it with water, and then bury the junction box and switch box with M 10 polymer cement mortar.
3) After pipeline laying, the groove shall be filled with polymer cement mortar, and glass fiber grid cloth with a width not less than 100mm shall be pasted outward along the length of the groove.
6, decoration construction
1) mortar strength grade
(1) Masonry mortar: the compressive strength and bond strength of masonry mortar should be slightly higher than the strength of block itself, and the wall should be built with high-performance special mortar, and the bond strength between masonry mortar and block should be ≥0.3MPa.
(2) Plastering mortar: The compressive strength and bond strength of plastering mortar should be slightly higher than the strength of the block itself, and the measured bond strength of plastering layer should be ≥0.4MPa.
2) Construction process of wall plastering project
Basic treatment → pretreatment (gray decoration, screed, finding the angle of yin and yang) → bottom and middle plastering → surface plastering.
3) Key points and requirements of construction operation
Before the wall plastering construction, the dust, laitance and other media that affect the bonding on the wall base should be removed; You can also sprinkle water the day before construction to reduce the dust at the grass-roots level, but you should strictly control the amount of sprinkling water on the masonry.
4) Plastering requirements
(1) Exterior wall plastering
A, the plastering layer (leveling layer) on the surface of the external wall should also be used as the waterproof layer of the wall: plastering with special plastering mortar mixed with a single bundle of high-strength fibers has high adhesion, crack resistance and impermeability.
B, exterior wall plastering layer and ceramic tile decoration layer should be set control joint. Exterior wall plastering layer, each layer should be set with a horizontal control joint. The horizontal control joint should be set at the bottom of the side beam; For the tile facing layer of the external wall, a horizontal control joint should be set every second floor. When the single width of the external wall is more than 5m, vertical control joints shall be set.
C control joint: the width of control joint should be 3.0 ~ 5.0 mm, and its depth should be the same as or 2/3 of the thickness of plastering layer. Control joints shall be filled with high-performance polyurethane sealant.
(2) interior wall plastering
A, should adapt to the characteristics of wall materials, and have good crack resistance and impermeability of special mortar.
B, the thickness of plastering layer: the ordinary plastering of interior wall shall not exceed 20mm, and the advanced plastering of interior wall shall not exceed 25mm.
C. Corner protection of the wall: All external corners of the interior wall are plastered with special mortar mixed with polyethylene single-bundle high-strength fiber, with a corner protection of 2000mm high and 50mm wide on both sides, and plastic corner protection is adopted.
D, holes and grooves of buried pipelines shall be plastered with special cement mortar in layers, and alkali-resistant glass fiber mesh cloth shall be pasted along the seam length to prevent cracks, and then plastered in layers.
E, wall plastering layer thickness should be ≥8.0mm or higher, each plaster thickness should be controlled within the scope of15 mm.. When the construction thickness of plastering layer is greater than 20mm, multi-channel sizing construction should be carried out, and the plastering interval time should be greater than 12 hours.
F, the surface of the plaster layer should be protoplasm screeding calender. If it is difficult to operate, it can be coated with clear water and then smoothed with a gray knife.
5) Processing requirements of concrete structure foundation
Concrete structures should be washed clean within 48 hours after formwork removal.
6) Finishing layer
A, block wall should be brushed on both sides, and the facing layer should be made of light materials such as thin paint and latex paint. The exterior walls of high-rise buildings should not be tiled. When sticking bricks, special adhesive should be used, and the bonding strength should not be lower than 0.4MPa.
B, block wall shall not be directly hung with heavy decorative layers such as stone; When necessary, all stone loads borne by steel members shall be borne by concrete ring beams between the main structure and the floor or concrete constructional columns between blocks, and shall not be borne by blocks. The steel parts used shall be made of stainless steel.
C, before the shop is stuck metope ceramic tile (or brick), should be clean at the grass-roots level, and full brush a layer of waterproof agent. When pasting, it is advisable to smear the adhesive on the back of the wall or ceramic tile (tile) with toothed mud tablets or other tools, and caulk it after 24 hours. Outdoor paving and caulking are strictly prohibited in rainy and snowy days.
D, surface coating engineering, pasting and soft package engineering should be carried out according to the Code for Quality Acceptance of Building Decoration Engineering (GB503 10).
Step 7 accept
1) The wall surface shall be smooth and clean, and there shall be no glue overflow at the mortar joint.
2) Masonry mortar joint should be full, with a thickness (width) of 2~3mm. The plumpness of horizontal and vertical mortar joints shall be ≥80%.
3) The overlapping length of upper and lower skin blocks should not be less than 1/3 of the block length, and the vertical joint should not be greater than two skins.
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