CN108118712A

CN108118712A - The construction method on large-sized concrete basis

Info

Publication number: CN108118712A
Application number: CN201810026491.5A
Authority: CN
Inventors: 朱奎
Original assignee: Individual
Current assignee: Individual
Priority date: 2016-03-30
Filing date: 2016-03-30
Publication date: 2018-06-05
Also published as: CN108193689A; CN108118711A; CN105926656A; CN105926656B; CN108193690A; CN108193691A

Abstract

The invention discloses a kind of construction methods on large-sized concrete basis, it is characterized in that huge foundation is equidistant successively from left to right to be divided into four casting area, each casting area indwelling, which is delayed, pours region, it is slow to pour the right that region is retained in casting area, in construction, four casting area concrete are each poured, the slow region concrete that pours is using expansive concrete, concrete hole is set inside huge foundation, flyash is mixed in concrete to reduce cement consumption, cement is using the low slag cements of the heat of hydration；Calcium lignosulfonate water-reducing agent is mixed, after concrete smears receipts pressure final set with wood, showering curing is no less than 7d after adding straw mattress covering using plastic film in time.Form removal selects concreting to carry out after 7 days, and when maintenance, which will fully water, soaks wooden model.

Description

The construction method on large-sized concrete basis

Technical field

The present invention relates to a kind of construction method on large-sized concrete basis, suitable for building field.

Background technology

As modern high-rise building continues to bring out, volume of concrete foundation occurs now and then in engineering construction.Large volume Concrete foundation can generate temperature stress since concrete square amount is larger during concrete coagulation, if without effective Phenomena such as technical measures, huge foundation is present with cracking.It can see from the forming process in crack, concrete particularly large volume is mixed Why solidifying earth foundation cracks, between the tensile strength of the tensile stress and concrete foundation that mainly concrete is born in itself The result of contradiction development.Thus in order to control volume of concrete foundation crack, coagulation soil matrix just must be as much as possible improved Plinth tensile strength properties itself and reduction temperature stress.

The content of the invention

The present invention is to provide a kind of construction method on large-sized concrete basis, solves asking for volume of concrete foundation cracking Topic.

The present invention starts with to alleviate in terms of four temperature stress problem, and one, hole is set inside huge foundation Concrete square amount is reduced, load-carrying properties do not have big weakening, while concrete material after setting hole inside huge foundation Material has larger saving；Two reduce temperature stress by setting the adjustment of concreting mode；Three are constructed by structure Measure reduces temperature stress；Temperature stress is reduced by material reasonable selection.

According to simulation analysis of computer, larger temperature stress band is present in 1/4~1/3 region of huge foundation, this Huge foundation is equidistant successively from left to right in invention is divided into four casting area, and each casting area indwelling, which is delayed, pours region, Slow to pour the right that region is retained in casting area, slow zone length of pouring is 600~800mm, and in construction, four casting area are mixed Solidifying soil is each poured, each delay pour region concrete after each region concreting finish 10~12 it is small when after carry out again It pours, hydration reaction can be generated after each region concreting, so as to be present with higher temperature, each region has poured mixed Solidifying soil can obtain the release of temperature stress in slow region of pouring, and each delay and pour region concrete and each region casting concrete Intermittent phase it is suitable, prevent this position New-old concrete from not connecting well, the intermittent phase of the invention is that a large number of experiments obtains .For the slow region concrete that pours using expansive concrete, the non-slow region concrete strength that pours of expansive concrete intensity ratio improves one A strength grade gives larger swelling stress in the larger section of shrinkage stress.It is slow to pour region concrete incorporation retarder, delay The Slow setting time for pouring region concrete extends 4h than casting concrete, so that the slow region concrete that pours is given to provide ortho position lateral spacing, Inside concrete is enable to generate stress and offsets part concrete pulling stress, so as to reduce or remit the appearance in crack.

Region is poured slow and non-slow pour buries tension distributing bar at Local handover, tension distributing bar a diameter of 6~ 8mm, tension distributing bar spacing are 50~100mm, and tension distributing bar symmetrically configures for upper and lower two layers along section.Slow Region and the non-slow concrete that pours at Local handover are poured because the tensile stress shunk or other reasons generate just is held by tension distributing bar Load, so as to effectively limit the expansion in crack.

Radiation muscle is placed in each region corner of huge foundation, a diameter of 14~18mm of muscle is radiated, due to temperature change And concrete shrinkage, stress concentration can be generated and cause crack, radiation muscle can avoid this phenomenon well.

Malthoid is laid between huge foundation and following concrete cushion, malthoid serves not only as waterproof layer, is also used as Sliding layer.Temperature shrinkage stress can be generated since border has constraint, huge foundation on the contact surface of outer constraint with setting Sliding surface can weaken outer constraint significantly, and malthoid plays the role of sliding layer.

Concrete hole is set inside huge foundation, and concrete hole realizes that leather bag material is used using leather bag airing form The rubber of 5mm thickness, can bear enough pressure.Suction nozzle in leather bag one end is installed, and pressure gauge and ball valve are housed, favorably It is inflated in gas pressure and control in control leather bag.Leather bag is first tentatively inflated in a pre-installation, and the preliminary the blowing pressure of leather bag is 0.02MPa after leather bag places, is inflated with air pump again, makes to stop inflation, Ran Houke when air pressure reaches final pressure in leather bag To continue to pour to completion.Leather bag inflation final pressure is determined according to concrete hole diameter, be less than when concrete hole is a diameter of or During equal to 75mm, leather bag inflation final pressure uses 0.04MPa；It is more than 75mm and less than or equal to 100mm when concrete hole is a diameter of When, leather bag inflation final pressure uses 0.05MPa；When concrete hole it is a diameter of be more than 100mm and less than or equal to 125mm when, leather bag It inflates final pressure and uses 0.06MPa；When concrete hole it is a diameter of be more than 125mm and less than or equal to 150mm when, leather bag inflation final pressure Using 0.07MPa；When concrete hole is a diameter of is more than 150mm, leather bag inflation final pressure uses 0.08MPa.Leather bag external coating New machine oil, in favor of the demoulding.

After concreting completion 12h, you can leather bag is deflated, is extracted out.Due between concrete and the rubber of leather bag Air in bonding and leather bag cannot release completely, so leather bag surface is most of or connects together with concrete, it is difficult to will It is extracted out.It is tentatively demoulded using Simple reinforced bar excystation device, a diameter of 2 25mm of reinforcing bar excystation device mobile jib are welded Reinforcing bar, steel bar end weld oval steel reinforcement cage, and bar diameter is 12mm used by oval steel reinforcement cage, is wrapped up outside reinforcing bar Adhesive plaster, to prevent reinforcing bar or reinforcement welding connector from scratching leather bag.Reinforcing bar excystation device is inserted into the bonding crack of leather bag and concrete, It gently rocks on one side, while insertion.Manually extraction leather bag may be employed after leather bag is tentatively separated with concrete.

Mass concrete cement consumption is no more than 350kg/m³, flyash is mixed in concrete to reduce cement Dosage, fly-ash-contained for the 5%~10% of cement quality, cement is using the low slag cements of the heat of hydration, to reduce coagulation The surface crack or crosscutting concern of native component.

The water consumption of hydration reaction only needs 20%~25% in concrete, and if water consumption is excessive, these are in concrete Water evaporation after, concrete can be made to generate a large amount of pores, and increase the shrinkage of concrete, can also influence its impermeability. In order to not only reduce with water but also can meet the pumpability of concrete and workability requirement, calcium lignosulfonate water-reducing agent, calcium lignosulfonate water-reducing agent are mixed For the 0.25% of cement consumption.

Concrete coarse aggregate uses rubble of the grain size for 5~40mm.Traditional coarse aggregate size be 5~25mm, smaller grain Footpath will reach concrete design strength requirement, and cement consumption can increase, and can equally concrete shrinkage be caused to increase.

The slump of traditional pump concrete is excessive, the pump concrete slump be 14~16cm, pour beam slab only with Vibrating head is made firm by ramming, then catches up with flat concrete with wooden rule, and floor is also easy to produce the plastic shrinkage of early concrete there is leakiness of vibrating And the common quality defect of sedimentation contraction fissure.The appropriate slump for reducing concrete of the invention, the pump concrete slump use 10 ~12cm receives pressure twice before initial set with wood floated, and plastic shrinkage and sedimentation draw seam is avoided to generate.

Do not answer form removal eraly, form removal carries out after selecting concreting 7 days, and when maintenance, which will fully water, soaks wooden model, Not only it can radiate but also can keep the temperature, the waterproof construction on the outside of abutment wall should be carried out after form removal as early as possible, and promptly be backfilling and compacted the earthwork at any time, this Sample can utilize moisture in soil to continue curing concrete, to achieve the purpose that prevent crack from generating.

After concrete smears receipts pressure final set with wood, showering curing is no less than 7d after adding straw mattress covering using plastic film in time. After concrete casting complete, the heat of hydration makes internal temperature reach certain temperature, if not being capped straw mattress heat preservation on a plastic film, then The internal difference in temperature of formation can make the stress that inside concrete generates overstep the extreme limit, and concrete surface is made to generate crack；In addition, When swashing acute decline, concrete can be shunk temperature, generated tensile stress, growth and concrete with the age of concrete The raising of intensity itself, it is also more and more big to the constraint of the shrinkage stress of cooling, if Concrete intensity insufficient at this time is to support Resist this shrinkage stress, can also generate crack.Plastic film adds water seasoning after straw mattress covering, it is ensured that in course of hardening It shrinks smaller, it is Chong Die with temperature drop peak value and generate crack to avoid dehydration shrinkage.

Reliable in quality of the present invention, it is easy to operate.

Specific embodiment

Huge foundation is equidistant successively from left to right in the present embodiment is divided into four casting area, and each casting area is stayed It puts to delay and pours region, slow to pour the right that region is retained in casting area, slow zone length of pouring is 600~800mm, in construction four Casting area concrete is each poured, each slow to pour region concrete to treat that each region concreting finishes 10~12 small Shi Houzai is poured, and for the slow region concrete that pours using expansive concrete, expansive concrete intensity ratio is non-slow to pour region concrete Intensity improves a strength grade, slow to pour region concrete incorporation retarder, and the slow Slow setting time for pouring region concrete is poured than It builds concrete and extends 4h.

Region is poured slow and non-slow pour buries tension distributing bar at Local handover, tension distributing bar a diameter of 6~ 8mm, tension distributing bar spacing are 50~100mm, and tension distributing bar symmetrically configures for upper and lower two layers along section.

Place radiation muscle, a diameter of 14~18mm of radiation muscle in each region corner of huge foundation.

Malthoid is laid between huge foundation and following concrete cushion.

Concrete hole is set inside huge foundation, and concrete hole realizes that leather bag material is used using leather bag airing form The rubber of 5mm thickness.Suction nozzle is installed in leather bag one end, and equipped with pressure gauge and ball valve.Leather bag is first tentatively filled in a pre-installation Gas, the preliminary the blowing pressure of leather bag are 0.02MPa, after leather bag places, are inflated again with air pump, reach air pressure in leather bag Stop inflation during final pressure, may then continue with and pour to completion.Leather bag inflation final pressure is determined according to concrete hole diameter, when Concrete hole it is a diameter of be less than or equal to 75mm when, leather bag inflation final pressure use 0.04MPa；It is more than when concrete hole is a diameter of 75mm and less than or equal to 100mm when, leather bag inflation final pressure use 0.05MPa；When concrete hole is a diameter of more than 100mm and small When 125mm, leather bag inflation final pressure uses 0.06MPa；It is more than and 125mm and is less than or equal to when concrete hole is a diameter of During 150mm, leather bag inflation final pressure uses 0.07MPa；When concrete hole is a diameter of is more than 150mm, leather bag inflation final pressure uses 0.08MPa.The new machine oil of leather bag external coating.

Mass concrete cement consumption is no more than 350kg/m³, flyash is mixed in concrete to reduce cement Dosage, fly-ash-contained for the 5%~10% of cement quality, cement is using the low slag cements of the heat of hydration.

Calcium lignosulfonate water-reducing agent is mixed, calcium lignosulfonate water-reducing agent is the 0.25% of cement consumption.Concrete coarse aggregate use grain size for 5~ The rubble of 40mm.The pump concrete slump uses 10~12cm, receives pressure twice with wood floated before initial set, plasticity is avoided to receive Contracting and sedimentation draw seam generate.

Form removal selects concreting to carry out after 7 days, and when maintenance, which will fully water, soaks wooden model, can not only radiate but also can protect Temperature should carry out the waterproof construction on the outside of abutment wall, and promptly be backfilling and compacted the earthwork at any time as early as possible after form removal.

After concrete smears receipts pressure final set with wood, showering curing is no less than 7d after adding straw mattress covering using plastic film in time.

Claims

1. a kind of construction method on large-sized concrete basis, it is characterized in that huge foundation is equidistant successively from left to right to be divided into four A casting area, each casting area indwelling, which is delayed, pours region, slow to pour the right that region is retained in casting area, slow to pour zone length For 600~800mm, in construction, four casting area concrete are each poured, it is each it is slow pour region concrete treat it is each Region concreting finish 10~12 it is small when after poured again, the slow region concrete that pours is using expansive concrete, swelled mixture The solidifying non-slow region concrete strength that pours of soil intensity ratio improves a strength grade, delays and pours region concrete incorporation retarder, slow to pour The Slow setting time of region concrete extends 4h than casting concrete；Concrete hole is set inside huge foundation；Large volume base Plinth concrete cement dosage is no more than 350kg/m³, flyash is mixed in concrete to reduce cement consumption, flyash incorporation It measures as the 5%~10% of cement quality, cement is using the low slag cements of the heat of hydration；Mix calcium lignosulfonate water-reducing agent, calcium lignosulfonate water-reducing agent For the 0.25% of cement consumption；Concrete coarse aggregate uses rubble of the grain size for 5~40mm；Concrete smears receipts pressure final set with wood Afterwards, showering curing is no less than 7d after adding straw mattress covering using plastic film in time；The pump concrete slump uses 10~12cm, Pressure is received with wood floated twice, plastic shrinkage and sedimentation draw seam is avoided to generate before initial set；

Form removal selects concreting to carry out after 7 days, and when maintenance, which will fully water, soaks wooden model, can not only radiate but also can keep the temperature, The waterproof construction on the outside of abutment wall should be carried out after form removal as early as possible, and is promptly backfilling and compacted the earthwork at any time.