Cast-in-situ concrete pouring construction framework structure
1 scope
The technology standard is applicable to general cast-in-site frame and frame shear wall concrete casting engineering.
2 construction preparation
2.1 material and main equipments:
2.1.1 cement: more than 325 slag Portland cement and ordinary Portland cement. Comes into play must have a certificate of quality and second-round exam test report.
2.1.2 sand: appropriate USES coarse sand and medium sand. Below C30 concrete, silt content is not more than 5%, higher than the C30, no greater than 3%.
2.1.3 stones: the particle size of 0.5 ~ 3.2 cm, below C30 concrete, silt content is not more than 2%, higher than the C30, no greater than 1%.
2.1.4 admixture, fly ash, its content should be determined by test, and shall comply with relevant standards.
2.1.5 concrete additive, water reducing agent and early strength agent shall comply with the provisions of the relevant standards, its content after test meet the requirements, shall be used.
2.1.6 main machines: apply to concrete mixer, the scale (or automatic measuring equipment), two-wheeled cart, small dumper, sharp spade, shovel, concrete skip, internal vibrator, long wood float, float, iron ruler, rubber hoses, iron plate, string of barrel, tower crane, etc.
2.2 operation conditions.
2.2.1 template, reinforced concrete layer, embedded parts and pipeline installation, all tests comply with the design requirements, and completed implicit, preview procedures.
2.2.2 pouring concrete frame and. Have pitched, and upon passing the inspection.
2.2.3 cement, sand, stone and admixture on inspection conform to the requirements of the relevant standards, such as concrete of the laboratory has issued notice.
2.2.4 the scale (or automatic feeding system) approved by check, accurate measurement vibrator (rod) upon passing the examination test run.
2.2.5 master according to the construction scheme of operating team has to conduct a comprehensive technical clarificaiton, concrete pouring application has been approved.
3 operation process
3.1 technological process;
Homework to prepare to apply to concrete mixer, concrete and transport
Column, beam, plate, shear walls, the stairs and concrete pouring and vibrating curing
3.2 job preparation: before pouring the waste within the template, dirt and other debris and reinforcement on smeary clean, and check whether the reinforced cement mortar pad pad. Such as using the template and wet wood template should be watered. Pillars of the template again after removing debris and water cleaning mouth should be closed. Scissors walls of loose concrete has the clean shave.
Concrete mixing 3.3:
3.3.1 according to the mixture ratio to determine the dosage of every plate of various materials and vehicle weight, respectively fixed cement, sand and stone the standard scale. In the car when weighing, often should determine aggregate moisture content, timely adjustment of proportion of water consumption, water added to ensure accurate.
3.3.2 rainfall distribution on 10-12 charging order: general pour the stone, cement, reload the sand. If you want to add admixture of fly ash, should join along with cement. For mineral admixtures (water reducing agent, leveling agent, etc.), the powder should be according to the rehearsals for the amount of each dish is put into a small bag inside it is advisable to (plastic bags), available with thickness of aggregate to join at the same time; Liquid should be per disk usage in blender mixing with water at the same time.
3.3.3 stirring time: in order to make the concrete mix, since all played a concrete mix into the mixing drum began to discharge, the shortest time, concrete mixing can be used as stipulated in the table 4-34.
Concrete mixing in the shortest time (s) table 4-34
Mixer out shoes (L)
< 250 > 250 ~ 500, 500
Since the fall, 90, 120, 150
Forced to 60, 90, 120
Since the fall, 90, 90, 120
Forced 60 60, 90
3.3.4 concrete began to stir, head of technical department by construction unit, foreman organize relevant personnel to acquired the slump and workability of concrete and so on carries on the appraisal, check whether conform to the requirements of the mixing proportion notice, adjusted the qualified before formal stirring.
Transportation: concrete since blender discharge, should be timely sent to the pouring location. In the process of transportation, to prevent segregation, the slurry erosion, slump change and produce the phenomenon such as initial setting. As to concrete pouring location have segregation phenomenon, should be carried out before casting secondary mixing.
Concrete after discharge from the mixer to the duration of the casting, should not be more than the provisions of table 4-35.
Concrete from the mixer discharge to pouring over time (min) table 4-35
Air temperature (℃)
Less than 25 above 25
< C30, 120, 90
< C30 90 60
Note: use a rapid hardening cement mixed with admixture or mixing concrete, shall be determined according to the test.
Must ensure that when the concrete pump pumping concrete continuous work, in the event of failure, idle time more than 45 min or concrete appear segregation phenomenon, should immediately flush the tube with pressure water or other method of residual concrete.
3.5 concrete pouring and vibrating of general requirements:
3.5.1 track of the concrete pour free from skip mouth falling height shall not be more than 2 m, measures must be taken when casting such as more than 3 m, with a string of chute barrel or etc.
3.5.2 concrete should be segmented, layered continuous casting layer height should be determined according to the structural characteristics, reinforcement density, are generally vibrator part length of l. 25 times, most less than 50 cm.
Internal vibrator used 3.5.3 should fast slow pull, point to homogeneous permutation, point by point, order, shall not be missed, do even vibrated. Mobile spacing is not greater than 1.5 times that of the vibrating action radius (generally is 30 ~ 40 cm). Should be inserted into the lower vibration on a layer of 5 cm, to eliminate the seam between the two layers. Surface vibrator (or plate vibrator) mobile spacing, should guarantee the vibrator plate cover has the edge of the vibrating part.
3.5.4 concrete should be continuous. If must be intermittent, the intermittent time should be shortened as far as possible, and before the concrete sets should be in the top layer, the first layer of concrete pouring is completed. Maximum intermittent time should be used according to the varieties of cement, determine the condensation temperature and concrete conditions, generally more than 2 h shall be in accordance with the construction joint treatment.
2.6.2 template should be often observed when pouring concrete, steel bar, reserved holes and embedded parts and steel dowel for mobile, deformation or congestion, found that the problem should be dealt with immediately, and shall be revised in before have been pouring concrete condensation in good condition.
3.6 column concrete pouring:
3.6.1 track at the bottom of the column before pouring should fill out with same concrete mix proportion with 5 ~ 10 cm thick cut stone mortar, column should be layered vibrating of concrete, thickness of each layer when using internal vibrator is not more than 50 cm, vibrating rod may not touch the steel bar and embedded parts. In addition to the above vibrating, the next thing to someone banging on the template at any time.
3.6.2 column within 3 m high, can be directly under the pillars gray casting, more than 3 m, the measures should be taken to (with a string of barrels) or in open doors hole on the side of the template installation inclined chute poured subsection. An altitude of no more than 2 m each and every template closed the doors after concrete pouring hole sealed, strapped tightly with straps.
3.6.3 concrete pillars shall be a casting finished, if you want to leave should be in below the main girder construction joints. Girderless floor should stay under the cap. With the beam slab casting is whole, should be in the column after the pouring down l ~ 1.5 h, give its preliminary heavy fact, continue casting.
3.6.4 radar echoes captured after pouring, shall, from time to time, will flow out lap steel finishing.
Beam, slab concrete pouring 3.7:
3.7.1 beam and plate should be at the same time casting, casting method should begin with "cast slurry method" by the end, the first casting beams, according to the high beam stratified pouring into step, when reached the bottom of the plate position again with concrete slab casting, with the constant extension step, beam and slab concrete pouring continuous forward.
3.7.2 and plate into the overall height is greater than lm beam, allow separate casting, the construction joints shall be out of the board at the end of the following 2 ~ 3 cm. Cast, the pouring and vibrating must work closely, the first layer of blanking slowly, after fully vibrated beam bottom layer material, use "cast slurry method" keep mud water along the bottom of the beam package stones to move forward, each layer shall be vibrated before blanking, the bottom of the beam and beam help site must pay attention to the vibrating and vibrating shall not touch the steel bar and embedded parts.
3.7.3 beam-column joints steel bar is dense, pouring the concrete time with small particle size of gravel with strength grade of concrete pouring, vibrating rod vibration with small diameter.
3.7.4 casting slab concrete virtual height should be slightly bigger than the thickness of vibrating back and forth with the vibrator vertical casting direction, thick plate available internal vibrator tora in the casting direction vibration, and the iron ruler check the thickness of the concrete, vibrating finished with long wood float screeding. Construction joints or there are embedded parts and steel dowel with wood float leveling. Are not allowed to use when casting slab concrete vibrating rod PuTan concrete.
3.7.5 construction joint position; Appropriate direction along the second beam casting slab, construction joints should be retained in the middle of the second beam span a third range. Surface should be without construction joints or board face perpendicular to the beam axis, shall not be left oblique if. Construction joints should be fastened with wood or steel wire net.
3.7.6 construction joints must stay has been pouring concrete compressive strength is not less than 1.2 MPa, is allowed to continue pouring. Before continue pouring concrete, construction joints of concrete surface should be cut hair, remove the floating stones, and water is rinsed clean, after first sprinkle a layer of cement slurry, and then continue pouring concrete, should be careful operation vibrated, the old and new concrete.
3.8 the concrete shear walls are:
3.8.1 such as column, wall of concrete strength grade, at the same time can also pouring, whereas appropriate column before pouring concrete, anchoring reinforcement embedded shear wall, after being open mould, then tie steel shear wall, the mould, pouring concrete.
Before 3.8.2 concrete shear walls are uniform in the bottom pouring 5 cm thick and wall body composition is the same cement mortar, concrete with shovel into the die, not be used hopper directly into the mould.
3.8.3 casting wall concrete should be continuous, interval time should not be more than 2 h, control the thickness of each layer of casting 60 cm, must therefore be arranged in advance under the concrete material point location and number of vibrator operator.
3.8.4 vibrating rod mobile spacing should be less than 50 cm, each point of the duration of vibration in surface laitance for degrees, to enable the lower level of concrete combined into a whole, 5 cm should be inserted into the lower concrete vibrator. Note when vibrating reinforced dense and the hole positions, to prevent leakage. Must be in the hole on both sides of the vibrating at the same time, not grey height will be broadly. Big mouth of the hole bottom template should speak, and casting vibration starts here.
3.8.5 concrete wall casting, to a flowing out of steel and arrange them, use wood trowel according to concrete leveling elevation lines to the wall surface.
The stairs concrete pouring 3.9:
3.9.1 stair section concrete pouring from bottom to top, vibrated slab concrete first, achieve step position and then concrete is poured together with concrete steps, constantly pushing up continuously, and ready to use wood trowel (or plastic float) will step on the surface smooth.
: the seam position 3.9.2 stair concrete appropriate continuous casting the stairways, construction joints shall be retained in the period of a third part of the stairs.
3.10 maintenance: after the concrete pouring, should cover within 12 h and watering, watering frequency should be able to maintain enough wetting state, concrete curing period is generally not less than seven days and nights.
3.11 winter construction:
3.11.1 winter casting of negative temperature concrete mixed with compound admixture, should according to different temperature conditions, the negative temperature using different admixtures. And before use must through the special test and technical appraisal about the unit. Column, wall maintenance appropriate USES curing spirit.
3.11.2 winter winter construction plan should be established before construction, heating for raw materials, mixing, transportation, pouring and curing of computation, and should be on the basis of the construction.
3.11.3 before pouring concrete, should clear the snow and ice on the template and reinforced, dirt. Transport and pouring concrete containers should have heat preservation measures.
3.11.4 transport casting process, the temperature should be consistent with the thermal calculation of certain data, such as discrepancy, measures should be taken to adjust. Before using heat curing, concrete curing temperature shall not be less than 2 ℃.
3.11.5 monolithic structure heat curing, casting process and construction joint position, should be able to prevent larger temperature stress, such as heating temperature 40 ℃, solicit opinions from the design units should be determined after. Ascending and descending temperature shall not exceed the standard concrete rules.
3.11.6 winter construction in the - 5 ℃, average temperature, average construction by adopting the composite heat storage method, the early strength type antifreezing admixture used should be the factory that are subject to laboratory test blocks, and contrast test before formal use. Comprehensive heat storage method appropriate chooses more than 425 R ordinary Portland cement or type of early strength cement. Admixtures should choose can significantly improve the early strength, and can reduce the strength of the antifreeze critical powder composite admixture, and aggregate to join at the same time, ensure uniform mixing.
3.11.7: curing winter template and insulation, cooling to 5 ℃ should be in the concrete rear can dismantle. Concrete temperature difference with the outside world is greater than 15 ℃, the concrete surface after ripping, should be temporarily override, make its slow cooling.
3.11.8 concrete block in addition to the normal number of sets of rules making, should also add two groups with structure of condition maintenance, a group in order to test the strength of the concrete seas before, another group to the strength of the inspection to room temperature curing 28 d.
3.11.9 winter construction process, should fill in "concrete engineering construction records" and "winter concrete construction journal".
4 quality standards
4.1 ensure projects:
4.4.1 concrete used in cement, water, aggregate, admixtures and must conform to the specifications and the relevant provisions of inspection factory certificate or test report is in line with the quality requirements.
4.1.2 the mixing proportion of concrete, metering, mixing of raw materials and maintenance and construction joint treatment, must comply with the rules and regulations of construction.
4.1.3 the strength of concrete block sampling, production, maintenance and testing in accordance with the concrete strength inspection evaluation standard (GBJ107-87).
4.1.4 design does not allow fracture structure, it is strictly prohibited cracks, design allows fracture structure, the crack width must comply with the design requirements.
4.2 the basic items: concrete should be vibrating compaction; Honeycomb, holes, can not have, such as cracks, slag inclusion defects.
4.3 allowable deviation projects, see table 4-36.
5 finished product protection
5.1 to ensure the accurate location of the reinforcing steel bar and block, can not hit the floor, staircase curved bar, don't touch the embedded parts and steel dowel.
5.2 don't clog pound template, not on the crane girder or stair step template help stamped on, should be built for the springboard, protection template solid and tight.
5.3 the stair step 3 has casting slab, stair step on the surface of concrete to protect, must be in the strength of concrete is 1.2 MP. After the party must operate in surface and installation of the structure with stents and templates.
Concrete cast-in-situ framework allowing deviation table 4-36
Allowable deviation (mm)
Monolayer multilayer high-level framework
1 the axis displacement 8 5 'quantity check
High layer + 10 + / - 5
All high plus or minus 30 plus or minus 30
3 column, wall and beam section size + 8-5 + 5 'quantity check
Each layer of 5 5
5 the perpendicularity of the column, wall overall height H / 1000
And no more than 20 H / 1000
And not more than 30
In 2 m by 5 surface roughness 8 8 feet and wedge feeler check
Embed steel centerline offset 10 10 6
7 embedded pipe, the reserved hole centerline offset May 5
8 embedded bolt centerline offset May 5
9 the reserved hole center location deviation 15 15
Wellbore length, width
The center line of + 25
- 0 + 25
0
H / 1000
And no more than 30 H / 1000
And not more than 30
Note: column H, high walls.
Winter construction in 5.4 has poured on the template of cover, on the scaffolding operation in the shop, try not to step footprints.
6 should pay attention to quality problems
Honeycomb 6.1: a blanking is too thick, the reason is that concrete vibrating false or leakage, there is crack template slurry erosion, steel bar is dense and concrete slump through small pebbles or big, column, there is crack template, so that poured out of the bottom of the mortar and concrete.
6.2 exposure: the reason is reinforced cushion block displacement, spacing is too large, leakage and reinforced against templates, exposure, or the bottom of the beam and plate vibration false, also possible exposure.
Pits: 6.3 to early to dismantle or template brush surface leakage isolation agent or template wet enough, component surface concrete cause pitting surface peeling easy adhesion in the template.
6.4 holes: dense part reason is reinforced concrete was stuck, without the upper vibrating keep pouring concrete.
6.5 gap and slag layer: the construction joint of cleaning not net or not watering the bottom slurry, easy to cause cracks, slag layer.
6.6 beam and column joint section size deviation is too large, the main reason is that template column joint stiffness poor or branch of the template was not seriously the control section size.
6.7 cast-in-place floor and stair step on surface roughness deviation is too big, the main reason is that after the concrete pouring, the surface don't float carefully erased. Winter construction in covering the insulation layer, here early or plate.
7 quality records
This technology standard should have the following quality records:
7.1 cement factory quality certificate and second-round exam report to approach.
7.2 stone test report.
7.3 test report.
7.4 admixture factory quality certificate and test report approach.
7.5 additive factory quality certification and try in jun reports, product specifications.
7.6 concrete test record.
7.7 notice of proportion of concrete construction.
7.8 concrete block strength test report.
7.9 concrete strength statistical evaluation form.
7.10 item of concrete engineering quality inspection.
7.11 concrete construction log (including winter construction records).
1 scope
The technology standard is applicable to general cast-in-site frame and frame shear wall concrete casting engineering.
2 construction preparation
2.1 material and main equipments:
2.1.1 cement: more than 325 slag Portland cement and ordinary Portland cement. Comes into play must have a certificate of quality and second-round exam test report.
2.1.2 sand: appropriate USES coarse sand and medium sand. Below C30 concrete, silt content is not more than 5%, higher than the C30, no greater than 3%.
2.1.3 stones: the particle size of 0.5 ~ 3.2 cm, below C30 concrete, silt content is not more than 2%, higher than the C30, no greater than 1%.
2.1.4 admixture, fly ash, its content should be determined by test, and shall comply with relevant standards.
2.1.5 concrete additive, water reducing agent and early strength agent shall comply with the provisions of the relevant standards, its content after test meet the requirements, shall be used.
2.1.6 main machines: apply to concrete mixer, the scale (or automatic measuring equipment), two-wheeled cart, small dumper, sharp spade, shovel, concrete skip, internal vibrator, long wood float, float, iron ruler, rubber hoses, iron plate, string of barrel, tower crane, etc.
2.2 operation conditions.
2.2.1 template, reinforced concrete layer, embedded parts and pipeline installation, all tests comply with the design requirements, and completed implicit, preview procedures.
2.2.2 pouring concrete frame and. Have pitched, and upon passing the inspection.
2.2.3 cement, sand, stone and admixture on inspection conform to the requirements of the relevant standards, such as concrete of the laboratory has issued notice.
2.2.4 the scale (or automatic feeding system) approved by check, accurate measurement vibrator (rod) upon passing the examination test run.
2.2.5 master according to the construction scheme of operating team has to conduct a comprehensive technical clarificaiton, concrete pouring application has been approved.
3 operation process
3.1 technological process;
Homework to prepare to apply to concrete mixer, concrete and transport
Column, beam, plate, shear walls, the stairs and concrete pouring and vibrating curing
3.2 job preparation: before pouring the waste within the template, dirt and other debris and reinforcement on smeary clean, and check whether the reinforced cement mortar pad pad. Such as using the template and wet wood template should be watered. Pillars of the template again after removing debris and water cleaning mouth should be closed. Scissors walls of loose concrete has the clean shave.
Concrete mixing 3.3:
3.3.1 according to the mixture ratio to determine the dosage of every plate of various materials and vehicle weight, respectively fixed cement, sand and stone the standard scale. In the car when weighing, often should determine aggregate moisture content, timely adjustment of proportion of water consumption, water added to ensure accurate.
3.3.2 rainfall distribution on 10-12 charging order: general pour the stone, cement, reload the sand. If you want to add admixture of fly ash, should join along with cement. For mineral admixtures (water reducing agent, leveling agent, etc.), the powder should be according to the rehearsals for the amount of each dish is put into a small bag inside it is advisable to (plastic bags), available with thickness of aggregate to join at the same time; Liquid should be per disk usage in blender mixing with water at the same time.
3.3.3 stirring time: in order to make the concrete mix, since all played a concrete mix into the mixing drum began to discharge, the shortest time, concrete mixing can be used as stipulated in the table 4-34.
Concrete mixing in the shortest time (s) table 4-34
Mixer out shoes (L)
< 250 > 250 ~ 500, 500
Since the fall, 90, 120, 150
Forced to 60, 90, 120
Since the fall, 90, 90, 120
Forced 60 60, 90
3.3.4 concrete began to stir, head of technical department by construction unit, foreman organize relevant personnel to acquired the slump and workability of concrete and so on carries on the appraisal, check whether conform to the requirements of the mixing proportion notice, adjusted the qualified before formal stirring.
Transportation: concrete since blender discharge, should be timely sent to the pouring location. In the process of transportation, to prevent segregation, the slurry erosion, slump change and produce the phenomenon such as initial setting. As to concrete pouring location have segregation phenomenon, should be carried out before casting secondary mixing.
Concrete after discharge from the mixer to the duration of the casting, should not be more than the provisions of table 4-35.
Concrete from the mixer discharge to pouring over time (min) table 4-35
Air temperature (℃)
Less than 25 above 25
< C30, 120, 90
< C30 90 60
Note: use a rapid hardening cement mixed with admixture or mixing concrete, shall be determined according to the test.
Must ensure that when the concrete pump pumping concrete continuous work, in the event of failure, idle time more than 45 min or concrete appear segregation phenomenon, should immediately flush the tube with pressure water or other method of residual concrete.
3.5 concrete pouring and vibrating of general requirements:
3.5.1 track of the concrete pour free from skip mouth falling height shall not be more than 2 m, measures must be taken when casting such as more than 3 m, with a string of chute barrel or etc.
3.5.2 concrete should be segmented, layered continuous casting layer height should be determined according to the structural characteristics, reinforcement density, are generally vibrator part length of l. 25 times, most less than 50 cm.
Internal vibrator used 3.5.3 should fast slow pull, point to homogeneous permutation, point by point, order, shall not be missed, do even vibrated. Mobile spacing is not greater than 1.5 times that of the vibrating action radius (generally is 30 ~ 40 cm). Should be inserted into the lower vibration on a layer of 5 cm, to eliminate the seam between the two layers. Surface vibrator (or plate vibrator) mobile spacing, should guarantee the vibrator plate cover has the edge of the vibrating part.
3.5.4 concrete should be continuous. If must be intermittent, the intermittent time should be shortened as far as possible, and before the concrete sets should be in the top layer, the first layer of concrete pouring is completed. Maximum intermittent time should be used according to the varieties of cement, determine the condensation temperature and concrete conditions, generally more than 2 h shall be in accordance with the construction joint treatment.
2.6.2 template should be often observed when pouring concrete, steel bar, reserved holes and embedded parts and steel dowel for mobile, deformation or congestion, found that the problem should be dealt with immediately, and shall be revised in before have been pouring concrete condensation in good condition.
3.6 column concrete pouring:
3.6.1 track at the bottom of the column before pouring should fill out with same concrete mix proportion with 5 ~ 10 cm thick cut stone mortar, column should be layered vibrating of concrete, thickness of each layer when using internal vibrator is not more than 50 cm, vibrating rod may not touch the steel bar and embedded parts. In addition to the above vibrating, the next thing to someone banging on the template at any time.
3.6.2 column within 3 m high, can be directly under the pillars gray casting, more than 3 m, the measures should be taken to (with a string of barrels) or in open doors hole on the side of the template installation inclined chute poured subsection. An altitude of no more than 2 m each and every template closed the doors after concrete pouring hole sealed, strapped tightly with straps.
3.6.3 concrete pillars shall be a casting finished, if you want to leave should be in below the main girder construction joints. Girderless floor should stay under the cap. With the beam slab casting is whole, should be in the column after the pouring down l ~ 1.5 h, give its preliminary heavy fact, continue casting.
3.6.4 radar echoes captured after pouring, shall, from time to time, will flow out lap steel finishing.
Beam, slab concrete pouring 3.7:
3.7.1 beam and plate should be at the same time casting, casting method should begin with "cast slurry method" by the end, the first casting beams, according to the high beam stratified pouring into step, when reached the bottom of the plate position again with concrete slab casting, with the constant extension step, beam and slab concrete pouring continuous forward.
3.7.2 and plate into the overall height is greater than lm beam, allow separate casting, the construction joints shall be out of the board at the end of the following 2 ~ 3 cm. Cast, the pouring and vibrating must work closely, the first layer of blanking slowly, after fully vibrated beam bottom layer material, use "cast slurry method" keep mud water along the bottom of the beam package stones to move forward, each layer shall be vibrated before blanking, the bottom of the beam and beam help site must pay attention to the vibrating and vibrating shall not touch the steel bar and embedded parts.
3.7.3 beam-column joints steel bar is dense, pouring the concrete time with small particle size of gravel with strength grade of concrete pouring, vibrating rod vibration with small diameter.
3.7.4 casting slab concrete virtual height should be slightly bigger than the thickness of vibrating back and forth with the vibrator vertical casting direction, thick plate available internal vibrator tora in the casting direction vibration, and the iron ruler check the thickness of the concrete, vibrating finished with long wood float screeding. Construction joints or there are embedded parts and steel dowel with wood float leveling. Are not allowed to use when casting slab concrete vibrating rod PuTan concrete.
3.7.5 construction joint position; Appropriate direction along the second beam casting slab, construction joints should be retained in the middle of the second beam span a third range. Surface should be without construction joints or board face perpendicular to the beam axis, shall not be left oblique if. Construction joints should be fastened with wood or steel wire net.
3.7.6 construction joints must stay has been pouring concrete compressive strength is not less than 1.2 MPa, is allowed to continue pouring. Before continue pouring concrete, construction joints of concrete surface should be cut hair, remove the floating stones, and water is rinsed clean, after first sprinkle a layer of cement slurry, and then continue pouring concrete, should be careful operation vibrated, the old and new concrete.
3.8 the concrete shear walls are:
3.8.1 such as column, wall of concrete strength grade, at the same time can also pouring, whereas appropriate column before pouring concrete, anchoring reinforcement embedded shear wall, after being open mould, then tie steel shear wall, the mould, pouring concrete.
Before 3.8.2 concrete shear walls are uniform in the bottom pouring 5 cm thick and wall body composition is the same cement mortar, concrete with shovel into the die, not be used hopper directly into the mould.
3.8.3 casting wall concrete should be continuous, interval time should not be more than 2 h, control the thickness of each layer of casting 60 cm, must therefore be arranged in advance under the concrete material point location and number of vibrator operator.
3.8.4 vibrating rod mobile spacing should be less than 50 cm, each point of the duration of vibration in surface laitance for degrees, to enable the lower level of concrete combined into a whole, 5 cm should be inserted into the lower concrete vibrator. Note when vibrating reinforced dense and the hole positions, to prevent leakage. Must be in the hole on both sides of the vibrating at the same time, not grey height will be broadly. Big mouth of the hole bottom template should speak, and casting vibration starts here.
3.8.5 concrete wall casting, to a flowing out of steel and arrange them, use wood trowel according to concrete leveling elevation lines to the wall surface.
The stairs concrete pouring 3.9:
3.9.1 stair section concrete pouring from bottom to top, vibrated slab concrete first, achieve step position and then concrete is poured together with concrete steps, constantly pushing up continuously, and ready to use wood trowel (or plastic float) will step on the surface smooth.
: the seam position 3.9.2 stair concrete appropriate continuous casting the stairways, construction joints shall be retained in the period of a third part of the stairs.
3.10 maintenance: after the concrete pouring, should cover within 12 h and watering, watering frequency should be able to maintain enough wetting state, concrete curing period is generally not less than seven days and nights.
3.11 winter construction:
3.11.1 winter casting of negative temperature concrete mixed with compound admixture, should according to different temperature conditions, the negative temperature using different admixtures. And before use must through the special test and technical appraisal about the unit. Column, wall maintenance appropriate USES curing spirit.
3.11.2 winter winter construction plan should be established before construction, heating for raw materials, mixing, transportation, pouring and curing of computation, and should be on the basis of the construction.
3.11.3 before pouring concrete, should clear the snow and ice on the template and reinforced, dirt. Transport and pouring concrete containers should have heat preservation measures.
3.11.4 transport casting process, the temperature should be consistent with the thermal calculation of certain data, such as discrepancy, measures should be taken to adjust. Before using heat curing, concrete curing temperature shall not be less than 2 ℃.
3.11.5 monolithic structure heat curing, casting process and construction joint position, should be able to prevent larger temperature stress, such as heating temperature 40 ℃, solicit opinions from the design units should be determined after. Ascending and descending temperature shall not exceed the standard concrete rules.
3.11.6 winter construction in the - 5 ℃, average temperature, average construction by adopting the composite heat storage method, the early strength type antifreezing admixture used should be the factory that are subject to laboratory test blocks, and contrast test before formal use. Comprehensive heat storage method appropriate chooses more than 425 R ordinary Portland cement or type of early strength cement. Admixtures should choose can significantly improve the early strength, and can reduce the strength of the antifreeze critical powder composite admixture, and aggregate to join at the same time, ensure uniform mixing.
3.11.7: curing winter template and insulation, cooling to 5 ℃ should be in the concrete rear can dismantle. Concrete temperature difference with the outside world is greater than 15 ℃, the concrete surface after ripping, should be temporarily override, make its slow cooling.
3.11.8 concrete block in addition to the normal number of sets of rules making, should also add two groups with structure of condition maintenance, a group in order to test the strength of the concrete seas before, another group to the strength of the inspection to room temperature curing 28 d.
3.11.9 winter construction process, should fill in "concrete engineering construction records" and "winter concrete construction journal".
4 quality standards
4.1 ensure projects:
4.4.1 concrete used in cement, water, aggregate, admixtures and must conform to the specifications and the relevant provisions of inspection factory certificate or test report is in line with the quality requirements.
4.1.2 the mixing proportion of concrete, metering, mixing of raw materials and maintenance and construction joint treatment, must comply with the rules and regulations of construction.
4.1.3 the strength of concrete block sampling, production, maintenance and testing in accordance with the concrete strength inspection evaluation standard (GBJ107-87).
4.1.4 design does not allow fracture structure, it is strictly prohibited cracks, design allows fracture structure, the crack width must comply with the design requirements.
4.2 the basic items: concrete should be vibrating compaction; Honeycomb, holes, can not have, such as cracks, slag inclusion defects.
4.3 allowable deviation projects, see table 4-36.
5 finished product protection
5.1 to ensure the accurate location of the reinforcing steel bar and block, can not hit the floor, staircase curved bar, don't touch the embedded parts and steel dowel.
5.2 don't clog pound template, not on the crane girder or stair step template help stamped on, should be built for the springboard, protection template solid and tight.
5.3 the stair step 3 has casting slab, stair step on the surface of concrete to protect, must be in the strength of concrete is 1.2 MP. After the party must operate in surface and installation of the structure with stents and templates.
Concrete cast-in-situ framework allowing deviation table 4-36
Allowable deviation (mm)
Monolayer multilayer high-level framework
1 the axis displacement 8 5 'quantity check
High layer + 10 + / - 5
All high plus or minus 30 plus or minus 30
3 column, wall and beam section size + 8-5 + 5 'quantity check
Each layer of 5 5
5 the perpendicularity of the column, wall overall height H / 1000
And no more than 20 H / 1000
And not more than 30
In 2 m by 5 surface roughness 8 8 feet and wedge feeler check
Embed steel centerline offset 10 10 6
7 embedded pipe, the reserved hole centerline offset May 5
8 embedded bolt centerline offset May 5
9 the reserved hole center location deviation 15 15
Wellbore length, width
The center line of + 25
- 0 + 25
0
H / 1000
And no more than 30 H / 1000
And not more than 30
Note: column H, high walls.
Winter construction in 5.4 has poured on the template of cover, on the scaffolding operation in the shop, try not to step footprints.
6 should pay attention to quality problems
Honeycomb 6.1: a blanking is too thick, the reason is that concrete vibrating false or leakage, there is crack template slurry erosion, steel bar is dense and concrete slump through small pebbles or big, column, there is crack template, so that poured out of the bottom of the mortar and concrete.
6.2 exposure: the reason is reinforced cushion block displacement, spacing is too large, leakage and reinforced against templates, exposure, or the bottom of the beam and plate vibration false, also possible exposure.
Pits: 6.3 to early to dismantle or template brush surface leakage isolation agent or template wet enough, component surface concrete cause pitting surface peeling easy adhesion in the template.
6.4 holes: dense part reason is reinforced concrete was stuck, without the upper vibrating keep pouring concrete.
6.5 gap and slag layer: the construction joint of cleaning not net or not watering the bottom slurry, easy to cause cracks, slag layer.
6.6 beam and column joint section size deviation is too large, the main reason is that template column joint stiffness poor or branch of the template was not seriously the control section size.
6.7 cast-in-place floor and stair step on surface roughness deviation is too big, the main reason is that after the concrete pouring, the surface don't float carefully erased. Winter construction in covering the insulation layer, here early or plate.
7 quality records
This technology standard should have the following quality records:
7.1 cement factory quality certificate and second-round exam report to approach.
7.2 stone test report.
7.3 test report.
7.4 admixture factory quality certificate and test report approach.
7.5 additive factory quality certification and try in jun reports, product specifications.
7.6 concrete test record.
7.7 notice of proportion of concrete construction.
7.8 concrete block strength test report.
7.9 concrete strength statistical evaluation form.
7.10 item of concrete engineering quality inspection.
7.11 concrete construction log (including winter construction records).
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