JP2985689B2 - Transporting and placing fresh concrete - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of transporting and placing fresh concrete, and more particularly to a construction site which requires a long time from the production of concrete to the placement of fresh concrete, such as when long-distance transportation is required. The present invention relates to a method of transporting and placing concrete.

[0002]

2. Description of the Related Art In general, concrete has different strengths depending on the type of aggregate and its mixing ratio, water-cement ratio, kneading time, temperature during transportation, and the like. In a concrete manufacturing plant or a concrete manufacturing plant having predetermined facilities, it is preferable to knead and manufacture as fresh concrete strictly planned and blended. The fresh concrete thus produced is transported to a casting site while stirring, for example, by a ready-mixed concrete truck (agitator truck).

[0003]

However [0007] In order to proceed hydration immediately after concrete kneading, quality such as slump and con Shisutenshi changes over time. That is, usually knead and then 2-3
When the time elapses, fresh concrete loses its initial fluidity and is difficult to cast. Therefore, when transporting concrete to a casting site using a ready-mixed concrete vehicle, for example, 1.5 to 2.0 hours according to JIS and the Society's specifications Is limited to the transport time, and thus the distance and range that can be transported between the concrete manufacturing site and the casting site are limited.

[0004] For this reason, for example, when concrete is transported over a long distance to a casting site located at a long distance, or when it takes a long time to pass through an area with heavy traffic such as an urban area, it takes a long time. In many cases, a limited time is exceeded, and therefore, even if such concrete is cast, there is a possibility that concrete having a predetermined quality cannot be obtained.

[0005] On the other hand, it is known that the hydration reaction of concrete is stopped when its temperature is -10 ° C or less. It is considered that the quality of fresh concrete is maintained for a long time.However, when actually applying it to the construction site, the work of freezing and transporting the fresh concrete, and the heating and thawing of the transported frozen concrete at the construction site are performed. At present, there is no established method for efficiently performing the setting work.

Accordingly, the present invention has been made in view of such a conventional problem, and includes an operation of freezing fresh concrete, an operation of transporting the frozen concrete,
It is another object of the present invention to provide a method of transporting and placing fresh concrete, which can efficiently perform a work of heating and thawing the transported frozen concrete at a construction site and placing it.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object, and the gist of the present invention is to introduce a kneaded fresh concrete into a freezing mold, and then to add a refrigerant to the mold. Liquefied gas is blown, the fresh concrete is frozen to at least −10 ° C. or less,
Next, a large number of frozen concrete blocks removed from each freezing form are collected, transported to a concrete placing site while being stored in a low-temperature tank, and the frozen concrete blocks are subjected to microwave irradiation or steam spraying at the placing site .
The present invention is directed to a method of transporting and placing fresh concrete, characterized in that it is heated and thawed and cast as fresh concrete.

Further, the method for transporting and placing fresh concrete according to the present invention comprises the steps of:
After charging into a freezing mold made of a flat dish-shaped container, the mold
A liquefied gas as a refrigerant is sprayed on the frame,
Freeze the cleats at least below -10 ° C and then
Multiple plate-shaped freezing concrete removed from the freezing mold
Blocks are stacked and stored in a low-temperature bath.
While transporting to the concrete placement site,
Heat and thaw the frozen concrete block
It is characterized by being cast as shu concrete.

[0009] In addition, transportation da設方method of fresh concrete of the present invention, the fresh concrete after kneading
Into a freezing mold made of a hollow cylindrical member.
One end is closed, and the other end is provided with a hanging member.
Part is buried in fresh concrete while projecting
After that, liquefied gas as a refrigerant is sprayed on the formwork,
Freeze concrete at least below -10 ° C
Then, from each freezing mold, the closed
By extruding frozen concrete from the end side,
A pillar-shaped frozen concrete block with a hanging member fixed to one end
Suspended frozen concrete blocks
Concrete while lowering and accumulating in a low temperature tank
Transport to the casting site, where the frozen condensate
Heat-thaw the reed block, fresh concrete
It is characterized by being cast as.

Further, the inner peripheral surface of the hollow cylindrical member may be subjected to Teflon processing by attaching a Teflon plate or applying Teflon.

[0011]

According to the method for transporting and placing fresh concrete of the present invention, fresh concrete is
By freezing below 10 ° C., the hydration reaction of fresh concrete can be stopped and transported, and each frozen concrete block is previously removed from the freezing formwork in a concrete manufacturing plant or a concrete manufacturing plant. Since it is loaded and transported to the casting site in the state, it is possible to easily perform a regeneration operation of the fresh concrete by a heating and thawing operation or the like at the concrete installation site.

Further, if a flat dish-shaped container is used as the freezing mold, a liquefied gas can be blown from the upper and lower surfaces of freshly poured fresh concrete to quickly form a frozen concrete block. Since the formed frozen concrete block has a flat plate shape, a large number of frozen concrete blocks can be accumulated by stacking the frozen concrete blocks, whereby the frozen concrete blocks can be efficiently transported.

Further, a hollow cylindrical member is used as the freezing mold, and one end of the cylindrical member is closed, fresh concrete is charged, and a hanging member is partially embedded in the fresh concrete at the other end. If the fresh concrete is frozen in a state where it is protruded and placed, the liquefied gas can be sprayed on many cylindrical members at once, and a large number of frozen concrete blocks can be formed efficiently, and the extruded frozen concrete can be formed. By suspending the block through a suspending member fixed to one end of the block, a large number of frozen concrete blocks can be easily collected and transported, and the inner peripheral surface of the hollow cylindrical member is processed with Teflon. With this arrangement, it is possible to easily take out the frozen concrete block from the tubular member.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic diagram showing a concrete distribution system and a thawing system for carrying out a method for transporting and placing fresh concrete according to a first embodiment of the present invention, and FIGS. 2 (a) and 2 (b) are the same. It is a perspective view which shows the lamination state of the formwork and frozen concrete block in an Example.

Referring to FIG. 1, the distribution system is constituted by a concrete distribution network for distributing a concrete manufacturing plant 1 and each casting site 2 via a cooling car 3.

The concrete manufacturing plant 1 is equipped with a batcher plant 4 and its auxiliary facilities, and equipment such as a freezing processing room 5 provided adjacent to the batcher plant 4.
The cooler truck 3 comes in contact with the rear opening at the exit of the above, and is transported and waited in a retrofitted state, so that the obtained frozen concrete blocks can be sequentially carried into the inside.

A transfer conveyor 6 is disposed between the lower part of the plant 4 and the processing chamber 5, and a batcher plant 4 is provided.
A mold 7 for freezing, which receives fresh concrete discharged at a fixed rate, is provided in a processing chamber 5 by a conveyor 6.
It is continuously transported inside.

Further, in the processing chamber 5, a plurality of cooling nozzles 8 arranged opposite to the upper and lower surfaces of each mold frame 7, a liquefied nitrogen gas cylinder 9 connected to the cooling nozzles 8 and an auxiliary device thereof, 6. A demolding device 10 disposed adjacent to the terminal end of No. 6 and a plurality of frozen concrete blocks C1 demolded by the demolding device 10 are stocked in a stacked state.
Equipped with a pallet 11 for transporting to the cooler 3 and an exhaust treatment facility (not shown), the empty form 7 after passing through the demolding device 10 is returned to the transport start end side of the conveyor 6 again for recycling. Further, a large number of frozen concrete blocks C1 stacked on the pallet 11 are sequentially loaded into the refrigerator car 3 through the outlet of the processing chamber 5.

On the other hand, in the concrete placing site 2, a thawing system 12, an agitator 14, a casting pump 15, a conveyor 16 and a conveyor 1
An extruder 17 for sequentially feeding the frozen concrete block C1 and the like are provided on the upper surface 6.

Then, in the concrete manufacturing plant 1, the batcher plant 4 mixes the measured cement, aggregate, and water at a predetermined mixing ratio, and when mixing is completed, as shown in FIG. Then, a fixed amount of fresh concrete C is discharged into the mold 7. Therefore, the conveyor 6 intermittently moves for each discharge operation.

Each mold 7 for freezing is a flat dish-shaped container made of iron plate as shown in the figure, and has an inner surface subjected to release processing such as Teflon or the like. To secure a large heat receiving area, and liquefy nitrogen gas from above and below the mold frame 7 to quickly freeze it. In addition, the size, volume, etc. are easy to handle for workers, and the efficiency during freezing and thawing,
It is set in consideration of load management.

The form 7 filled with concrete C
Is continuously conveyed into the processing chamber 5 through the conveyer 6, and liquid nitrogen is sprayed from the upper surface and the lower surface one after another through the cooling nozzle 8, and the concrete C is instantaneously frozen by rapidly removing latent heat of vaporization.

The freezing temperature is set at -10 ° C. or lower, which is the temperature at which the cement hydration reaction stops, but it is preferable to set the upper limit at -15 ° C. in consideration of a temperature rise during transportation or the like. The lower limit is not particularly specified, and can be lowered to about the boiling point of liquid nitrogen (−196 ° C.).
It is desirable to set to about ° C. That is, -1
Since the hydration reaction does not proceed after freezing at 0 ° C. or less, the concrete C is stored as fresh concrete until thawing.

The demolded frozen concrete C1
As shown in FIG. 2B, the pallets 11 are sequentially stacked on the pallet 11, and when the pallets 11 reach a certain height, the pallets 11 and the pallets 11 are stacked in a stacked state by a forklift or the like.

The cold storage vehicle 3 is set to have the same loading capacity as a ready-mixed concrete vehicle, and its loading portion is surrounded by a heat insulating material.
It is equipped with an auxiliary refrigerator etc. to keep it in a frozen state,
When the frozen concrete block C1 is fully loaded, the rear door is closed and transported to the casting site 2 through the transport route A.

The distance and the transport time of the transport route A are not limited by the hydration reaction of the concrete C and may be arbitrary, unlike the conventional one, but are naturally set in consideration of the transport efficiency.

Then, the frozen concrete C1 together with the pallet 11 is sequentially taken out of the cool truck 3 which has arrived at the casting site 2, and the taken out frozen concrete C1 is passed through the extruder 17 facing one end of the conveyor 16 in order from the top. And sequentially extruded onto the conveyor 16 and continuously sent to the thawing facility 12 through the conveyor 16. The empty pallet 11 is collected again in the cool car 3.

The thawing equipment 12 is provided with heating means by microwave irradiation, steam spraying or the like inside the thawing equipment 12.
1 is thawed in fresh concrete C. The thawing temperature may be at least a temperature exceeding −10 ° C. at which the hydration reaction proceeds.

The thawed concrete C is agitator 1
4 and continuously mixed and kneaded again to adjust fluctuations in composition due to icing, etc.
It is driven through. Note that the agitator 14 and the pump 15 are not always necessary, and the thawed concrete C can be poured as it is.

Then, all the frozen concrete blocks C1 have been delivered and the refrigerated truck 3 from which the pallets 11 have been recovered goes to the concrete manufacturing factory 1 again, is located at the same transport standby position as described above, Then, the factory 1 and the casting site 2 are reciprocated by the same operation as described above.

If a freezer for storage is provided in the factory 1, the frozen concrete can be stored in the freezer as it is, so that the concrete can be made and stored. If the compound according to the formula is stored in the freezer, the concrete loading operation of the corresponding specification can be carried out immediately according to the dispatch of the insulated truck at the corresponding site.

FIG. 3 shows a second embodiment of the present invention. This embodiment is basically incorporated in the same concrete distribution system as the first embodiment, and only the form, demolding and transport system are different, so the same reference numerals are used for the same parts, Description will be made by using different reference numerals only for parts.

In FIG. 3, a hollow cylindrical form 20 is
The inner surface of the cylinder 22 is made of a metal cylinder 22 provided with a piston 21 at one end, for example, by attaching a Teflon plate to the inner surface. The fresh concrete is frozen by spraying a liquefied gas to the outer periphery of the concrete to rapidly cool it, and then, in a frozen state, the piston 21 is connected to a jack 23, which is driven to extrude a cylindrical frozen concrete block C1. The frozen concrete block C1 is stored frozen.

After the concrete C is cast, a hook 24 as a hanging member is inserted into the opening of the cylinder 22 and frozen in this state, so that the hook 24 is attached to the end of the frozen concrete block C1 as shown in the figure. The frozen concrete block C1 is suspended through the hook 24, so that a large number of frozen concrete blocks C1 can be easily transported and stored.

[0035]

As described above in detail, according to the method for transporting and placing fresh concrete of the present invention, the hydration reaction of fresh concrete is stopped by freezing fresh concrete at -10 ° C or lower. The concrete blocks can be transported for long periods of time, and each frozen concrete block is loaded and transported to the casting site with the mold removed from the freezing formwork in advance at the concrete manufacturing plant or concrete manufacturing plant. It is possible to easily perform a fresh concrete regeneration operation such as a heating and thawing operation on site. That is, according to the present invention, the work of freezing fresh concrete, transporting the frozen concrete, and heating and thawing the transported frozen concrete at the construction site according to the situation at the construction site. Can be performed efficiently.

If a flat dish-shaped container is used as the freezing mold, a liquefied gas can be blown from the upper and lower surfaces of the fresh concrete charged thinly to quickly form a frozen concrete block. Since the formed frozen concrete block has a flat plate shape, a large number of frozen concrete blocks can be accumulated by stacking the frozen concrete blocks, whereby the frozen concrete blocks can be efficiently transported.

Further, a hollow cylindrical member is used as the freezing mold, and one end of the cylindrical member is closed, fresh concrete is charged, and a suspending member is partially embedded in the fresh concrete at the other end. If the fresh concrete is frozen in a state where it is protruded and placed, the liquefied gas can be sprayed on many cylindrical members at once, and a large number of frozen concrete blocks can be formed efficiently, and the extruded frozen concrete can be formed. By suspending the block through a suspending member fixed to one end of the block, a large number of frozen concrete blocks can be easily collected and transported, and the inner peripheral surface of the hollow cylindrical member is processed with Teflon. With this arrangement, it is possible to easily take out the frozen concrete block from the tubular member.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a concrete distribution system and a thawing system for carrying out a method for transporting and placing fresh concrete according to a first embodiment of the present invention.

FIGS. 2 (a) and 2 (b) are perspective views showing a stacked state of a formwork and a frozen concrete block in the first embodiment.

FIG. 3 is a perspective view of a mold according to a second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Concrete manufacturing factory 2 Concrete casting site 3 Cooler truck (low temperature tank) 4 Batcher plant 7, 20 Freezing formwork 5 Freezing processing room 8 Cooling nozzle 9 Liquefied nitrogen gas cylinder 10 Demolding device 24 Hook C Fresh concrete C1 Freezing concrete block

Continuation of the front page (56) References JP-A-6-193264 (JP, A) JP-A-1-96051 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) E04G 21 / 04

Claims (4)

(57) [Claims] 1. After kneading the fresh concrete after kneading into a freezing mold, a liquefied gas as a refrigerant is sprayed on the mold to cool the fresh concrete by at least -10.
℃ or less, then collects a large number of frozen concrete blocks removed from each freezing form, transports them to the concrete placing site while storing them in a low-temperature tank, and irradiates the frozen concrete blocks with microwaves at the placing site Or
A method of transporting and placing fresh concrete, characterized in that it is heated and thawed by steam spraying and is placed as fresh concrete. 2. Flattening the fresh concrete after kneading.
After being placed in a freezing mold made of a simple dish-shaped container,
A liquefied gas, which is a refrigerant, is blown, and the fresh concrete
Freeze the plate at least below -10 ° C, then freeze each
Many flat frozen concrete blocks removed from the formwork
While stacking locks and storing them in a low-temperature bath
Transport to concrete placement site
Heat and defrost the frozen concrete block and fresh
A method for transporting and placing fresh concrete, characterized by placing as concrete. 3. The fresh concrete after kneading is hollow.
One end of the cylindrical member is attached to a freezing mold formed of the cylindrical member.
Close and insert, and at the other end a hanging member
Buried in fresh concrete
Thereafter, a liquefied gas as a refrigerant is sprayed on the mold to
Freeze concrete at least below -10 ° C;
Then, from each freezing mold, the closed one end side of the tubular member
One end by extruding frozen concrete from
Pillar-shaped frozen concrete block with a hanging member fixed to it
Suspended frozen concrete blocks
Concrete while placing in a cold tank
Transport to the site and place the frozen concrete
Heat and thaw the block to make fresh concrete
A method for transporting and placing fresh concrete, characterized by placing and placing . 4. The method for transporting and placing fresh concrete according to claim 3, wherein the inner peripheral surface of the hollow cylindrical member is subjected to Teflon processing.