EP3362239B1 - Method for producing concrete pipes - Google Patents

Description

technical field

The invention relates to a method for producing concrete pipes in an upright casting mold with a mold space between a core and a jacket divided lengthwise and with mold sockets closing off the mold space at the top and bottom, flowable concrete being poured into the mold space and the concrete pipe being Setting of the concrete is demolded by opening the mantle.

In contrast to a vibrating press method, in a wet concrete pouring method flowable concrete is poured into the mold cavity of a mould, which means that the concrete body has to set in the mold before it can be removed from the mould. For the production of concrete pipes in vertical casting molds, this means that to demould the set pipe body, the split shell of the casting mold is opened either by expanding or radially pulling the shell halves apart and the diameter of the core is reduced. Since the upper mold sleeve is assigned to the shell, the upper mold sleeve must also be split. However, the upper mold socket must allow the flowable concrete to be poured into the mold space from above, which requires open-ended upper mold sockets with the disadvantage that the end faces of the pipe body in the area of the open end faces of the upper mold sockets have to be smoothed by hand, which is added to that the setting behavior of the flowable concrete poured into the mold space can hardly be taken into account. In the course of the setting process, the air bubbles enclosed in the flowable concrete escape upwards and can only partially escape through the open end face of the upper mold socket, so that the air bubbles collect in particular in the area of the outer peripheral wall of the upper mold socket Give rise to undesired air voids in the area of the offset, end-face coupling attachments of the finished concrete pipes.

It is known ( EP 0 476 245 A2 ), the upper mold sleeve is only pressed onto the compacted concrete body in a shaping manner after the concrete has been compacted by shaking, with the excess concrete being displaced from the mold space between the mold core and mold jacket, so that the area of the coupling attachment formed by the upper mold sleeve is also uniformly compacted Concrete body can be assumed. Apart from the fact that in contrast to a wet concrete casting process, the difficulties caused by air bubbles rising in the flowable concrete do not occur in a vibratory pressing process, the emergence of the excess concrete from the mold space is to be regarded as disadvantageous in this known vibratory pressing process for the production of tubular bodies. In addition, a relative movement between the mold core and the mold mantle is required in order to be able to close the annular opening between the upper mold sleeve and the core, which is necessary to displace the excess concrete from the mold space.

The DE-A1-33 23 340 and US-A1-2005/269747 disclose the closest prior art relating to a method for manufacturing concrete pipes according to the preamble of claim 1.

Presentation of the invention

The invention is therefore based on the object of designing a wet concrete casting method for producing concrete pipes in the mold space between a core and a shell of a standing mold in such a way that not only the prerequisites for a dimensionally accurate design of the coupling attachments formed by the upper mold sleeve are created, but also the The risk of air voids forming in the set pipe body is avoided and the setting behavior of the flowable concrete can be taken into account in a simple manner.

Based on a method of the type described above, the invention solves the task in that the free-flowing concrete is poured into the mold space in a predetermined amount when the upper mold sleeve is removed and that the upper mold sleeve forming a closed ring only occurs after a setting time for a predetermined setting volume of the cast tubular body between the core and the shell is pressed into the end face of the tubular body in a shaping manner.

Since the flowable concrete is poured into the mold space with the upper mold socket removed and the upper mold socket is only pressed into the still flowable concrete after a specified setting time, the air bubbles rising in the pipe body during the setting time can escape upwards unhindered through the upper mold socket, so that during the subsequent Compression molding of the end-face coupling approach by pressing the upper mold sleeve into the still flowable concrete, smooth wall surfaces are formed not only in the peripheral area, but also in the area of the end face. However, waiting for the setting process for the concrete poured into the mold cavity and the subsequent molding of the coupling attachment requires the mold cavity to be filled with a specified quantity of flowable concrete in order to be able to ensure a specified length of the concrete pipe to be produced. Accordingly, a filling volume must be provided that exceeds the volume of the concrete pipe to be produced by the setting volume. The setting behavior of different concrete compositions and thus the setting volume to be taken into account in each case can be determined in a simple manner, for example by tests. In practice, it has been found that after just a few minutes there is a settlement that allows compression molding through the upper mold sleeve within a specified manufacturing tolerance.

The compression molding of the end coupling attachment of the concrete pipe to be produced can be assisted by rotating the upper mold sleeve during and/or after pressing it into the flowable concrete.

Brief description of the drawing

Fig. 1

eine Gießform zur Durchführung eines erfindungsgemäßen Herstellungsverfahrens für Betonrohre in einem Axialschnitt mit einer vom Formraum abgehobenen oberen Formmuffe unmittelbar nach der Befüllung mit fließfähigem Beton,

Fig. 2

den Formraum zwischen Kern und Mantel der Gießform ausschnittsweise im Bereich der oberen Formmuffe nach dem Setzvorgang des Rohrkörpers aus fließfähigem Beton in einem größeren Maßstab und

Fig. 3

eine der Fig. 2 entsprechende Darstellung der Gießform nach dem formgebenden Eindrücken der oberen Formmuffe in den Rohrkörper.

The method according to the invention is explained in more detail with reference to the drawing. Show it

1

a casting mold for carrying out a production method for concrete pipes according to the invention in an axial section with an upper mold sleeve lifted from the mold space immediately after filling with flowable concrete,

2

the mold space between the core and the shell of the casting mold in a section in the area of the upper mold sleeve after the setting process of the tubular body made of flowable concrete on a larger scale and

3

one of the 2 Corresponding depiction of the casting mold after the upper mold sleeve has been pressed into the tubular body.

way of carrying out the invention

As can be seen in particular from the 1 can be seen, a casting mold for carrying out the wet concrete casting method according to the invention for the production of a concrete pipe has a base 1 with a core 2 and a jacket 3, between which and the core 2 an annular mold space 4 is formed. At the bottom, this mold space 4 is closed off by a mold sleeve 5 which rests on the base 1 and, in conjunction with the jacket 3, provides for the formation of an enlarged sleeve 6 at the lower end of the tubular body 7 made of concrete. For the formation of a sleeve 6 complementary, re-entrant, from the 3 The visible coupling attachment 8 at the opposite end of the tubular body 7 is served by a separate upper mold sleeve 9 in the form of a closed ring, which can be inserted coaxially with the casting mold between the core 2 and the jacket 3 into the annular space 4 and preferably rotated about its axis.

For demoulding a concrete pipe that has been produced, both the core 2 and the jacket 3 are usually designed to be divided lengthwise. While the jacket 3 must be pulled radially outwards from the concrete pipe to be removed from the mold, the core must be drawn in radially inwards from the concrete pipe in order to release the pipe body 7 . This is achieved in a known manner in that the longitudinal edges of the divided peripheral wall of the core 2 that run parallel to one another at a distance in the peripheral direction in the usage position of the core are pulled towards one another. In the case of a conical core design, a division of the core which would otherwise be necessary can also be omitted. The longitudinal edges of the divided jacket 3 lying against one another in the position of use of the jacket 3 are correspondingly pulled apart. In a one-piece design, the shell 3 is thus expanded, while in a two-piece design, the two shell halves are pulled apart.

To produce a concrete pipe, free-flowing concrete is poured in a predetermined amount, tailored to the pipe to be produced, into the mold space 4 between the core 2 and the shell of the mold when the upper mold sleeve 9 is lifted, usually from above in accordance with the 1 filled. In special cases, however, it is also possible to press the flowable concrete into the mold space 4 through an opening in the casing. Before the upper mold sleeve 9 is pressed into the tubular body 7 on flowable concrete in order to form a coupling attachment 8 , the tubular body 7 must be allowed to set. During this setting time, the fill level of the mold space 4 drops according to the 2 from an initial level 10 indicated by a dot-dash line to a level 11 with compaction of the concrete. In order to shorten the setting time, the jacket and/or the core can be provided with a vibration drive.

The air bubbles enclosed in the flowable concrete can escape upwards from the mold space 4 during this setting time, so that when the upper mold sleeve is then pressed into the flowable concrete between the core 2 and the jacket 3, the coupling attachment 8 is formed without pores and with smooth wall surfaces. It is only necessary to ensure that the when inserting the upper mold sleeve 9 into the mold space 4 , air collecting above the tubular body 7 can escape from the mold sleeve 9 , which is ensured by the required guide gap between the upper mold sleeve 9 and the core 2 .

After the concrete has set, which is necessary for demolding, the tubular body 7 can be demolded by opening the jacket 3 and pulling it apart radially outwards and pulling the core 2 in radially. The upper mold sleeve 9 can remain on the tubular body 7 during demoulding, but can also be removed beforehand.

Claims (2)

1. Method for producing concrete pipes in a vertical casting mould comprising a mould space (4) between a core (2) and a casing (3), which is divided longitudinally, and comprising mould sleeves (5, 9) which terminate the mould space (4) at the bottom and top, wherein pourable concrete is introduced into the mould space (4), and the pipe body (7) is removed from the mould after the concrete has set by opening the casing (3), characterised in that, with the upper mould sleeve (9) removed, the pourable concrete is introduced into the mould space (4) in a predetermined quantity corresponding to the volume of the concrete pipe to be produced and exceeding it by a setting volume, and in that the upper mould sleeve (9) which forms a closed ring is pressed into the end face of the pipe body (7) in a shaping manner between the core (2) and the casing (3) only after a setting time for the specified setting volume of the cast pipe body (7) and after the filling height of the mould space (4) has fallen during the setting time.
2. Method as claimed in claim 1, characterised in that the upper mould sleeve (9) is pressed into the pipe body (7) between the core (2) and the casing (3) and is rotated about its axis.

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