1 scope
This technology is applicable to industrial and civil
construction in the concrete foundation.
2 construction preparation
2.1 materials and equipment:
2.1.1 cement: appropriate uses, No. 325, ~425 Portland cement and slag Portland cement and ordinary 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 5~32mm, clay is less than 2%, and free of debris.
2.1.4 water: tap
water or clean water that contains no harmful substances.
2.1.5 admixture, admixture: its variety and quantity, should
be determined as necessary by the experiment.
2.1.6 major equipment: mixer, scale, cart dumpers, shovels (flat
head and pointy), the vibrator (plug-in plate of peace), scratch poles, wood float, hose, series barrel or chute.
2.2 operating conditions:
2.2.1 basic axis size, basement elevation and geological conditions are checked and should
be done hidden procedures.
2.2.2 Installing template has been checked and meets the design requirements, go through pre-clearance.
2.2.3 in the trough, wall or on the template flat on the concrete signs, large-area placement of base level nail about every 3M.
2.2.4 buried in the bedding in the heating and plumbing, electrical and
other pipelines have been installed, and interested
parties acceptance.
2.2.5 check concrete mix, check the background scales, technical clarification. Prepare concrete test mode.
3 operational processes
3.1 process:
Slot in the base or template cleanup → mixing concrete vibrated concrete → →
→ concrete curing
3.2 cleaning: on the ground or soil, clear the mud and debris, and waterproofing and drainage measures. Application for dry-soil water wet, should
be left on the surface of stagnant
water. In formwork panels clear garbage, mud and
other debris, and water wetting the wood template, plug the seams and holes.
3.3 concrete mixing: the background carefully according to
the concrete mix feed: each release order is gravel-cement sand → (admixture) → water (admixture). Strict control of water, stirring to evenly, the shortest time in the 90s.
3.4 concrete pouring
3.4.1 the feed opening of the concrete from the pouring of the concrete's surface height must
not exceed 2m. Liberal leaning down over 2m, the barrel should
be used,or chute.
3.4.2 the pouring of
the concrete layer continuous, lift height for vibrators part length of 1.25 times maximum does
not exceed 50cm.
3.4.3 the use of vibrating
needle quickly inserted slowly remove, insert points should
be uniformly arranged, point-by-point move, the order shall
not be omitted, so that vibration compacting. Mobile space with
a little Yu Zhen tamp in
the radius of 1.5times. Layer on the vibration should
be inserted in
the lower 5cm, to clear the seam between the two layers. Mobile space vibrating
Board, should guarantee a vibrator plate cover has
been vibrating edges.
3.4.4 not continuous pouring of concrete, 2H, should
be dealt with according to construction joints.
3.4.5 when pouring concrete, you should always observe the templates, bracket, pipe and reserved holes, embedded with or
without conditions. When deformation anddisplacement are found, should immediately stop pouring and handle in
a timely manner, and then continue to pour.
3.4.6 after vibration compacting of concrete, wooden trowel the surface rubbing.
3.4.7 the curing of concrete: after the concrete has
been poured, and should be covered in the 12h and watering, watering frequency should
be enough to keep concrete moist State. Curing period of not less
than 7 days and nights.
3.4.8 when rain, winter, open-air concrete seasonal construction plan shall
be established, to take effective measures to ensure the quality of concrete.
4 quality criteria
4.1 project:
4.1.1 cement used in concrete, water, aggregates, additives and
other provisions must conform to the relevant specifications and standards.
4.1.2 concrete mix
proportion and materials measuring, mixing, conservation and treatment of construction joints 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. Its strength must conform to
the provisions of the code.
4.1.4 design does
not allow for cracks in structures, no cracks; design allows structural cracks, the crack width must meet the design requirements.
4.2 the Foundation project:
4.2.1 vibration compacting, cellular area a is
not greater than 200cm2, today is not
more than 400cm2, no holes.
4.2.2 no cracks no slag layer.
4.3 allowable deviation, as shown in table 2-14.
Plain concrete foundations allow deviation table 2-14
Project tolerance (mm) test method
1 elevation ± 10 level or drawing a foot check
2 8 2m surface flatness on foot and wedged feeler
Gage check
3 base amount of axial displacement 15 using a theodolite or drawing-scale check
4 base size +
15-10 ' check
5 reserved hole center line 5-foot check
5 finished
product protection
5.1 in strength to ensure its surface and edges are not damaged due to removed template, removable side templates.
5.2 after the 1.2MPa poured concrete strength, on which pedestrians and upper
partof the construction.
5.3 in the construction, heating
and plumbing, electrical conduit should
be well protected and the hole, not collisions.
5.4 reserved according to design requirements, within the base holes or place bolts and embedded parts, in order to avoid sinking after concrete.
5.5 in winter construction of concrete surfaces should
be covered by insulation material to prevent the concrete frost.
6 quality problems to be noticed
6.1 concrete is not dense, honeycomb: mainly because of
the bad vibration, leak vibration mix no slot leakage caused the or template.
6.2 increase surface, elevation, size is not
allowed: horizontal lines or wood chunks are not
allowed
to sign, when not carefully leveled, or template support in prison and
other causes.
6.3 gaps slag: construction joint in concrete is
not
good, there is debris. Is not primarily caused by carefully cleaning the.
6.4 irregular cracks: basic and contract too long, upper
and lower concrete bad, conservation is not
enough, or removal caused premature.
7 quality records
This standard shall meet the following quality records
7.1 cement factory prove and retest proved.
7.2 template level, axes, dimensions, inspection records.
7.3 structure made of concrete test application form and mix orders issued by
the laboratory.
7.4 28D compressive
strength of standard curing concrete block test report. Commercial concrete factory certificate.
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