Concrete construction technology of cushion

1 scope

This technology is applicable for industrial and civil construction ground concrete liner construction operations.

2 construction preparation

2.1 materials and equipment:

2.1.1 cement: Yi No. 325, Portland cement and ordinary Portland cement and slag Portland cement.

2.1.2 sand: sand or coarse sand, clay is less than 5%.

2.1.3 the gravel: gravel or crushed rock, size 0.5~3.2mm, clay is less than 2%.

2.1.4 concrete mixers, scales, trolleys or dump truck, a sharp spade, shovel, plate vibrator, barrels or chute, scratch poles, wood trowel, rubber pipes, iron chisel and wire brush.

2.2 operating conditions:

2.2.1 quality of structure engineering has completed the acceptance procedure, door frame is installed, has been playing around the wall good +50cm level elevations.

2.2.2 the warm, guard pipelines across the floor was installed, it tube hole has fine stone concrete pouring and packing density.

2.2.3 laying horizontal tube has been done in the cushion and finished the hidden procedures.

2.2.4 in the pouring of the first floors before concrete pad, heating Groove and Groove through the Interior heater has done, finished and through the acceptance procedure of drainage pipe, indoor backfill for quality inspection and assessment.

3 operational processes

3.1 process:

Base treatment → find levels of elevation, elastic control vibrating line laying concrete concrete mixer → → → →

Leveling → conservation

3.1.1 base treatment: bonded on concrete laitance, loose concrete, mortar, scrape with a cold chisel, use wire brush away the cement slurry, and then use a broom to sweep.

3.1.2 bomb find elevation level control line: according to the level of +50cm on the wall elevations, measure down cushion height, there are conditions to play around on the wall.

3.1.3 concrete mixer

3.1.3.1 mix (its strength not less than C10), check the background materials, check the accuracy of the scales, made mixing all the preparations before. Back-office operators carefully according to the concrete mix feed, each release order are stones → → → cement sand water. Should strictly control the water, stirring to evenly, mixing time in the 90s.

3.1.3.2 of the surface engineering of building construction and acceptance specification for requirements of the production block. Block group number, in terms of surface engineering of architecture on each floor should not be less than one group. When each layer of surface engineering of building area of more than 1000m2, for each additional 1000m2 each of a set of blocks, less than 1000m2 on a 1000m2 basis.

3.1.4 the laying of concrete: concrete pad thickness should not be less than 60mm. In order to control the smoothness of the cushion, the first floors in the filling into small stakes (30mmx30mmx200mm), the horizontal elevation line flat on the mat at the stake marks (about 2m). In the floor on the concrete base 100mmx100mm, leveling Pier (with fine stone concrete), DUN glazing for elevation on the cushion.

Large cushion sections should be poured on the ground. Partition in relation to slot location of ground connection, different materials and device based location, divided.

Prior to the laying of concrete spraying water on the grass-roots moist, brushing a layer of pigment slurry (water than for 0.4~0.5), and then start laying from end, from the Interior to the outside back operation.

3.1.5 vibration: paving concrete with a spade, the thickness of slightly higher than the level, then plate vibrator vibrating. Thickness of more than 20cm, the vibrating needle should be used, and its radius of action of moving distance of not more than 1.5 times, do not leak, and ensuring concrete density.

3.1.6 leveling: after vibration compacting of concrete, horizontal level line on the wall and leveled to check for smoothness, high off a, hollow fill. Horizontal wood bars scraper scrape, rub wooden trowel flat on the surface. There are slope requirements of the ground should slope according to design requirements.

3.1.7 conservation: has finished pouring concrete pad, should be covered by 12h and water conservation should not be less than 7d.

3.1.8 winter operation, the ambient temperature should not be below + 5 c. Under negative temperature, such as construction, with antifreeze must be qualified through laboratory tests before use. Chloride content shall not be greater than the weight of cement 3%. Is less than, equal to, C10 concrete, in front of the cold concrete of compressive strength shall not be less than 5.0N/mm2.

4 quality criteria

4.1 project

4.1.1 cement used in concrete, water, aggregate and additives must comply with the provisions relating to the construction and.

4.1.2 concrete mix proportion, measurement of raw materials, mixing, conservation and construction joint treatment must comply with the provisions of the code.

4.1.3 evaluation of concrete strength of blocks must be in accordance with the standards of inspection and evaluation of concrete strength (GBJ107-87), sampling, production, maintenance and testing, which must comply with the provisions of the code.

4.2 allowable deviation, as shown in table 7-2.

Bedding concrete ground tolerance table 7-2

Serial number item tolerance (mm) test method

10 2m m on foot and 1 surface flatness wedge feeler Gage check

2 elevation ± 10 use level to check

3 incline less than 2/1000 of the relative size of the room, and not more than 30 adjustable triangle check

4 thickness in some places no more than 1/10 feet in thickness check

5 finished product protection

5.1 in the pad of poured layer of concrete intensity after 12MPa can only be allowed in their walk and carry on other operations.

5.2 in the construction process, the attention to transport concrete car don't touch moving door frame (should be protected in advance), and in the laying of concrete to protect electrical devices such as pipe.

5.3 concrete pad poured out to meet the conservation time, continued construction of surface layer, such as continued construction, the cushion should be covered to protect and avoid mixing mortar on the cushion. Store the bucket so as to avoid contamination, such as bedding, affect the bond strength of surface layer and layer and causes surface layer hollowing.

6 quality problems to be noticed

6.1 not compacting: mainly due to leakage vibration and vibration is not compact, or mix allowed and caused by the improper operation. Basement sprinkler at the end is too dry and the cushion is too thin, can also cause imperfect.

6.2 surface irregularities, levels are not allowed to: operation is not serious when leveling. Paving concrete must be based on the horizontal line while mastering the laying of concrete thickness, vibration level again after checking smoothness, high after filling, with a wooden scraper bar horizontal (or small stakes) for the standard shave.

6.3 irregular cracks: cushion size is too large, not fragmented warehouse construction, first warming layer of ditch cover plate is not concrete, backfill the first floors uneven sinking too much cushion thickness less than 60mm or pipelines and other factors, can lead to cracks.

7 quality records

This standard shall meet the following quality records:

7.1 cement factory certificate.

7.2 quality assessment for concrete blocks and concrete strength test record form.

7.3 ground waterproofing requirements, waterproof material factory certification and testing records, hidden inspection records.

7.4 cushion section for quality inspection and assessment of concrete form.