CN215866315U - Vibration and rotation combined forming device for simulating on-site pavement compaction - Google Patents
Vibration and rotation combined forming device for simulating on-site pavement compaction Download PDFInfo
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Abstract
The utility model discloses a vibration and rotation combined forming device for simulating on-site pavement compaction. Wherein, rotatory combination forming device of vibration includes: a test piece mold; the device comprises a device body, wherein a vibration pressure head and a test piece die matched with the vibration pressure head are arranged on the device body, the test piece die is provided with an internal space matched with the shape of the vibration pressure head, and the internal space of the test piece die is used for placing a test piece; and the rotary compaction instrument is provided with an accommodating space which can be adapted to accommodate the test piece mold. The vibration and rotation combined forming device is simple in structure and wide in application range, can excellently realize function switching of vibration compaction and rotation compaction, can realize better on-site compaction simulation by utilizing the vibration and rotation combined forming device, obtains more accurate experimental results for subsequent development of relevant experimental equipment, thereby better guiding on-site construction, and has excellent market value and application prospect.
Description
Technical Field
The utility model belongs to the technical field of road engineering bituminous pavement material forming equipment, and particularly relates to a vibration-rotation combined forming device for simulating field pavement compaction.
Background
At present, asphalt pavement material compacting equipment mainly relates to two kinds of asphalt pavement material compacting equipment, namely a vibration compacting instrument and a rotary compacting instrument (Superpassive compaction SGC).
At present, the indoor forming mode of the asphalt mixture mainly comprises the following steps: marshall compaction, wheel milling, static pressure, and rotary compaction. Once the marshall compaction method is published, the method is mainly used for simulating the impact compaction process of the road surface for military airport pavement of engineering soldiers in the united states and military and civil aviation airport pavement built by the federal aviation administration. With the development of asphalt pavement compaction equipment and techniques, the marshall compaction process has gradually deviated from on-site pavement compaction. The rotary compaction method better simulates the kneading effect in the field compaction process and is considered to be closest to the field pavement compaction effect, so the rotary compaction method is widely applied to the American asphalt mixture proportioning design. However, the gyratory compactor using the gyratory compaction method belongs to static shear and cannot simulate the dynamic effect of the vibratory roller caused by vibration well. In the market, the asphalt mixture vibrating compaction equipment does not form a unified standard, and cannot be applied and popularized in indoor forming.
For example, the vibratory asphalt compactor used in the prior art is manufactured in the united states and has the following specific structural parameters: vibration frequency 60Hz, static compressive stress 413.64 kpa. The vibration effect is only generated by two vibration motors connected to the vibration pressure head. Each vibration motor can provide minimum 445N and maximum 7126N of excitation force. The two vibrating motors provided a vibration pressure of 23.7kPa minimum and 358kPa maximum.
Another example is: chinese patent publication No. CN104729898A, published as 2015, 6, month 24 and entitled "asphalt mixture vibrating and rotary compacting apparatus" discloses an asphalt mixture vibrating and rotary compacting apparatus. In the technical solution disclosed in the patent document, the vibratory rotary compactor for asphalt mixture includes: the cylinder mould is used for containing the asphalt mixture, and an upper pressure head and a lower pressure head which are used for extruding the asphalt mixture in the cylinder mould from an upper surface and a lower surface are arranged in the cylinder mould; the upper pressure head is connected with an upper driving device for driving the upper pressure head to move up and down through a pressure rod, and the pressure rod is also provided with an excitation device for driving the upper pressure head to vibrate; and a rotary kneading device for driving the cylinder mould to do circular inclined rotary motion is arranged below the cylinder mould. However, it should be noted that the device has the following disadvantages: (1) the longitudinal rails of the device are two side walls of the counterforce frame 2; (2) the displacement meter of the device cannot accurately measure the vertical displacement of the pressure rod in the vibration process, and the displacement data in the vibration process is subjected to filtering processing; (3) vibrocompaction is controlled by a third displacement meter, not time; (4) the rotary compaction is controlled by times and cannot be controlled according to the height of the test piece; (5) the mold testing heat preservation temperature is 150 +/-5 ℃ according to the specification requirement, so that a displacement meter in the heat preservation box 25 needs to resist high temperature; (6) the vibration motor 4 does not show that the exciting force is adjustable; (7) the device has no automatic demoulding device; (8) the rotation angle of the device is determined by a spring device, and the angle stability is difficult to ensure in the rotation process.
For another example: the Chinese patent document with the publication number of CN1731129 and the publication date of 2006, 2 and 8 and named as an indoor asphalt mixture rotary vibration compactor discloses an indoor asphalt mixture rotary vibration compactor. In the solution disclosed in this patent document, the device has the following drawbacks: (1) the device is free of any displacement or pressure sensor; (2) the device can only adjust the initial static pressure stress, the nominal amplitude and the vibration frequency of vibration through the self weight of the balancing weight; (3) the device can only realize the simultaneous operation of rotary compaction and vibratory compaction, and the process cannot be controlled according to the number of rotations; (4) the vibration system lifting device of the device is a hand wheel instead of a cylinder; (5) the device does not show that the device can be used for rotary compaction at a certain rotation angle, and the rotary lower pressure head has no vertical displacement; (6) the device is only provided with one vibration motor, so that the horizontal force generated in the vibration process of the motor cannot be counteracted, and the excitation force of the motor is not shown to be adjustable; (7) the relative position of a mark post 9 and a scale 10 in the device can not be accurately 0.1mm to record the height change of a test piece; (8) the device is free of an automatic demoulding device; (9) this device requires the motor 16 to withstand the great stress of vibration due to structural defects.
Based on this, in order to better adapt to the development of on-site compacting equipment, a device is expected to be obtained, the device can better simulate on-site compacting, and a more accurate experimental result is obtained for the subsequent development of relevant experimental equipment so as to better guide on-site construction, and the device has excellent market value and application prospect.
SUMMERY OF THE UTILITY MODEL
In order to overcome the defects that the dynamic effect of a vibratory roller caused by vibration cannot be well simulated and the vibratory roller cannot be matched with other equipment such as indoor forming equipment or a rotary compaction instrument for use in the prior art, the utility model aims to provide a vibratory rotary combined forming method and a vibratory rotary combined forming device for simulating on-site road surface compaction. The vibration and rotation combined forming device is simple in structure and wide in application range, can excellently realize function switching of vibration compaction and rotation compaction, can realize better on-site compaction simulation by utilizing the vibration and rotation combined forming device, obtains more accurate experimental results for subsequent development of relevant experimental equipment, thereby better guiding on-site construction, and has excellent market value and application prospect.
In order to achieve the above object, the present invention proposes a vibratory rotary composite forming apparatus simulating on-site road compaction, the vibratory rotary composite forming apparatus comprising:
a test piece mold;
the device comprises a device body, wherein a vibration pressure head and a test piece die matched with the vibration pressure head are arranged on the device body, the test piece die is provided with an internal space matched with the shape of the vibration pressure head, and the internal space of the test piece die is used for placing a test piece;
and the rotary compaction instrument is provided with an accommodating space which can be used for accommodating the test piece mold in a matching manner.
According to the technical scheme, the specification of the vibration compaction test piece die is consistent with that of the conventional rotation compaction test piece die by modifying the vibration pressure head, and the combined forming test of vibration compaction and rotation compaction of the asphalt mixture is realized.
In addition, in some preferred embodiments, the vibrating and rotating combined forming device provided by the utility model can realize that the static pressure stress, the vibrating compaction frequency, the vibrating time, the nominal amplitude and the exciting force of the vibrating ram in the vibrating compaction process can be adjusted, so that the condition that the asphalt mixture is compacted on site can be better simulated, and more accurate experimental results can be obtained, so as to better guide the site construction.
Preferably, the matching arrangement of the vibration pressure head and the test piece mold is realized by any of the following modes:
the shape of the outer edge of the vibration pressure head is matched with the shape of the inner wall of the test piece mold in a structure;
the vibrating ram is free to move partially or fully in the axial direction of the specimen die.
Preferably, the bottom of the test piece mold is provided with a bottom support;
preferably, scales are engraved on the outer wall of the vibration pressure head, so that the height of the test piece in the test piece die in the vibration compaction process is displayed in real time.
Preferably, the device body includes:
the device comprises a device base, a test piece die and a test piece, wherein a die fixing base is arranged on the device base;
the wide-surface machine body upright columns are symmetrically arranged on two sides of the die fixing base;
the vibration mechanism is connected with the wide-face machine body upright column in a sliding manner through a sliding mechanism and is connected with the vibration pressure head;
the vibration pressure head adjusting mechanism comprises an air cylinder and an air compressor, and is connected with the vibration pressure head so as to adjust the static pressure stress of the vibration pressure head;
wherein, the lower extreme of vibration pressure head is located along the axial direction of device body to the test piece mould.
The static compressive stress can be adjusted by, for example, the air pressure of the air cylinder.
Preferably, the vibration mechanism comprises a vibration bracket and a vibration motor fixed on the vibration bracket, wherein two ends of the vibration motor are symmetrically provided with at least one eccentric mass block;
and/or the test piece mold is fixed on the mold fixing base through a test piece mold fixing piece;
and/or the base is fixed with the ground through bolts;
and/or, the sliding mechanism comprises a sliding groove and a sliding block arranged in the sliding groove, and the sliding block is connected with the vibration mechanism.
More preferably, when the number of the eccentric mass blocks is two, the included angle of the eccentric mass blocks is adjustable, and the magnitude of the exciting force of the vibration mechanism is adjusted by adjusting the size of the included angle of the eccentric mass blocks;
and/or the adjustable vibration time interval of the vibration mechanism is 0-10 minutes;
and/or the adjustable range of the motor vibration frequency of the vibration mechanism is 0-60 Hz;
and/or the static pressure stress adjustable interval of the vibration pressure head is 0-800 kPa;
and/or the test piece die fixing piece comprises at least one arc-shaped piece, and the bottom support is fixed on the base through a bolt by the arc-shaped piece;
and/or the base is fixed with the ground through bolts;
and/or the vibration motor comprises two motors which are symmetrically arranged along a vertical central axis of the device body, and the adjusting range of the exciting force of each motor is 0-13 kN.
It should be noted that, in the above embodiment, the mold fixing base is provided with a test piece mold fixing member, the test piece mold is fixed on the mold fixing base through the test piece mold fixing member, and the bottom support is the bottom support of the test piece mold.
In some preferred embodiments, for example, the vibration mechanism is comprised of a vibration cradle and a vibration motor, the vibration motor including two motors. (of course in some other embodiments, the number of motors included in the vibration motor may be set according to the specifics of each embodiment). Each motor can provide the maximum exciting force of 13kN, two eccentric mass blocks are respectively arranged at two ends of each motor, and the size of the exciting force can be adjusted by changing the size of an included angle between the two eccentric mass blocks (the adjustable range of the included angle is 10-100%).
Preferably, in some embodiments, each motor is set to have an adjustable vibration time interval of 0 to 10 minutes.
In some preferred embodiments, the adjustable range of the vibration frequency of each motor is set to be 0-60 Hz.
In addition, in some preferred embodiments, each of the vibration motors is fixed in the vibration support through a bolt, and when the vibration motors operate, one of the vibration motors rotates forwards and the other vibration motor rotates backwards to counteract horizontal exciting force.
Preferably, the device body further comprises a control box, and the control box is connected with the sliding mechanism and/or the vibrating mechanism;
and/or the vibration pressure head adjusting mechanism comprises an air cylinder and an air compressor, wherein a piston piece of the air cylinder is connected with the vibration pressure head.
More preferably, the control box is an electrical control box;
and/or the air cylinder and the air compressor are connected with the regulating valve through a pressure-resistant air pipe.
The positive progress effects of the utility model are as follows:
1) in the technical scheme of the utility model, the vibration pressure head and the test piece mold can be adjusted and matched according to the test requirements and the size of the test piece, the test piece mold is consistent with the specification of the conventional rotary compaction test piece mold, the combined forming test of vibration compaction and rotary compaction of the asphalt mixture (the test piece is the asphalt mixture in the technical scheme of the utility model) can be realized, and the finally obtained test piece has good forming effect. The test piece die of the vibration compaction instrument in the prior art has two types of cylindrical and rectangular shapes and is only suitable for vibration compaction tests.
2) According to the technical scheme, the specification of the vibration compaction test piece mold is consistent with that of the conventional rotation compaction test piece mold, after vibration compaction, the test piece mold is placed in a rotation compaction instrument to continue rotation compaction, and the test piece is automatically demoulded after being formed. Whereas the bottom of the prior art vibratory compactor manufactured in the united states is provided with a stripping device.
3) Compared with the prior art, the vibration and rotation combined forming device provided by the utility model realizes a combined forming test method of vibration compaction and rotation compaction for optimally simulating field construction compaction by modifying the vibration pressure head and enabling the size of a test piece mould to be consistent with the specification of a test piece mould of the conventional rotation compaction instrument so as to combine with the rotation compaction instrument (for example, according to field experience, after the indoor asphalt mixture is subjected to rotation compaction for 12 times, vibration compaction is carried out for a certain time, finally rotation compaction is carried out to a control height, and related performance tests can be carried out after the test piece is formed). The indoor test verifies that the testing device is effective, the testing efficiency is improved, the device is simple in structure and convenient to install and operate.
4) In addition, in some preferred embodiments of the utility model, the vibration frequency of the motor of the vibration mechanism of the vibration and rotation combined forming device is adjustable within the range of 0-60 Hz, but the vibration frequency of the vibration mechanism of the vibration and rotation combined forming device cannot be adjusted by the vibration compactor manufactured in the United states of America in the prior art.
5) In some preferred embodiments of the present invention, the vibration and rotation combined forming device of the present invention includes an air compressor and an air cylinder disposed on the top of the device (preferably, the pressure of the air storage tank of the air compressor and the air cylinder can be adjusted within a range of 0 to 800kPa), so as to adjust the static compressive stress of the vibration head, so that the static compressive stress is adjustable within a range of 0 to 800kPa, whereas the static compressive stress of the vibration compactor manufactured in the united states of america in the prior art is a fixed value and cannot be adjusted.
6) In some preferred embodiments of the present invention, the vibration motor used in the present invention can provide a maximum excitation force of 13kN, and when there are two or more vibration motors, each vibration motor can provide a maximum excitation force of 13 kN.
Drawings
FIG. 1 is a schematic structural diagram of a vibrating-rotating combined forming apparatus according to an embodiment of the present invention;
FIG. 2 is an isometric view of the apparatus body of one embodiment of the vibratory rotary composite molding apparatus of the present invention;
FIG. 3 is a schematic structural diagram of an apparatus body of an embodiment of the vibrating-rotating combined forming apparatus according to the present invention;
FIG. 4 is a schematic view from another perspective of the apparatus body structure of the vibrating rotating combined forming apparatus according to one embodiment of the present invention;
FIG. 5 schematically illustrates the apparatus body structure of the vibrating rotating combined forming apparatus according to an embodiment of the present invention from a further perspective;
FIG. 6 is a schematic view of a connection structure between a test piece mold and a base in one embodiment of the vibration and rotation combined molding apparatus of the present invention;
FIG. 7 is a schematic view of a connection structure between a specimen mold fixture and a base in one embodiment of the vibration and rotation combined molding apparatus of the present invention;
FIG. 8 is a schematic view of a base structure of a vibrating-rotating combined forming device according to an embodiment of the present invention;
FIG. 9 is a schematic view of an arc-shaped member of an embodiment of the vibrating rotating combined forming device according to the present invention;
FIG. 10 is a schematic view of a test piece mold of the vibration and rotation combined molding apparatus according to an embodiment of the present invention;
FIG. 11 is a schematic flow chart illustrating the use of the vibrating and rotating combined forming device according to one embodiment of the present invention;
FIG. 12 is a schematic view showing a flow chart of the vibration and rotation combined forming device according to another embodiment of the present invention.
Reference numerals
Vibrating and rotating the combined forming device 1; a device body 21; an air compressor 22; a gyratory compactor 23; an inner space P; a vibrating ram 211; a test piece mold 212; a base 213; broad-face fuselage pillars 214; a vibratory ram adjustment mechanism 215; a vibrating mechanism 216; a control box 217; a slide mechanism 218; the vibration bracket 2141; a vibration motor 2142; a specimen mold fixture 219; a mold fixing base 210; arcuate members 2191; a test piece mold test cylinder 2121; a shoe 2122; a first via 251 and a second via 252.
Detailed Description
The present invention will be more clearly and completely described in the following description of preferred embodiments, taken in conjunction with the accompanying drawings.
Example 1
Fig. 1 is a schematic structural diagram of a vibration and rotation combined forming device according to an embodiment of the present invention.
As shown in fig. 1, in the present embodiment, a vibratory rotary combined forming apparatus 1 is used to simulate an on-site asphalt compaction process. With further reference to fig. 1, in the present embodiment, the vibratory rotary combined molding apparatus 1 is further connected to the control box 217, so as to control the vibratory press head static pressure stress, the vibratory press frequency, the vibratory time, the nominal amplitude and the exciting force of the vibratory rotary combined molding apparatus 1 during the vibratory press process to be adjustable through the control box 217. Of course, it is preferred that in some embodiments, the control box 217 be an electrical control box.
As can be seen with further reference to fig. 1, in the present embodiment, the vibro-roto-molding apparatus 1 further comprises a gyratory compactor 23, the gyratory compactor 23 having an accommodating space P adapted to accommodate the specimen mold 212.
With respect to the structure of the vibration and rotation combined molding apparatus 1, specific reference may be made to fig. 2. FIG. 2 is an isometric view of the apparatus body of one embodiment of the oscillating rotary composite forming apparatus of the present invention.
As shown in fig. 2, the vibration and rotation combined molding apparatus 1 includes: the specimen mold 212, the apparatus body 21, and the gyratory compactor 23. in this embodiment, the gyratory compactor 23 is a PINE gyratory compactor, although in some other embodiments, other types of gyratory compactors may be used. The device body 21 is provided with a vibration pressure head 211 and a test piece mold 212 adapted to the vibration pressure head 211, the test piece mold 212 has an inner space adapted to the shape of the vibration pressure head 211, and the inner space of the test piece mold 212 is used for placing a test piece (in this embodiment, the test piece is an asphalt mixture).
It should be noted that the adaptive setting of the vibration ram 211 and the sample mold 212 is realized by any of the following manners:
the shape of the outer edge of the vibration pressure head 211 is matched with the shape of the inner wall of the test piece die 212 in a structure;
the oscillating ram 211 is free to move partially or fully in the axial direction of the specimen die 212.
In some preferred embodiments, the bottom of the test piece mold 212 is provided with a shoe.
Moreover, in some preferred embodiments, the outer wall of the vibration indenter 211 is marked with a scale to display the height of the test piece in the test piece mold during the vibration compaction process in real time.
As for the specific structure of the apparatus body 21, fig. 3 to 5 can be referred to. Fig. 3 is a schematic structural diagram of an apparatus body of a vibration-rotation combined forming apparatus according to an embodiment of the present invention; FIG. 4 is a schematic view from another perspective of the apparatus body structure of the vibrating rotating combined forming apparatus according to one embodiment of the present invention; fig. 5 schematically shows the apparatus body structure of the vibration and rotation combined molding apparatus according to an embodiment of the present invention from a further view.
As shown in fig. 2, and referring to fig. 3 to 5 as necessary, in the present embodiment, the apparatus body 21 includes: as further shown in fig. 2, the base 213 is fixed on the ground through bolts, the test piece mold 212 is connected with the mold fixing base 210 through a mold fixing member 219, and the related specific structure can refer to fig. 6 to 10; wide-face fuselage pillars 214 symmetrically disposed on both sides of the mold fixing base 210; a vibration mechanism 216 which is connected with the wide-face body upright 214 in a sliding way through a sliding mechanism 218, and the vibration mechanism 216 is connected with the vibration pressure head 211; a vibration ram adjusting mechanism 215 connected to the vibration ram 211 to adjust the static compressive stress of the vibration ram 211; and the specimen mold 212 is provided at the lower end of the vibration ram 211 in the axial direction of the apparatus body 21.
In some embodiments, to facilitate real-time display of the height of the test piece in the test piece mold during vibrocompaction, the outer wall of the vibroindenter 211 is graduated.
As can be seen from fig. 2 to 5, the vibration mechanism 216 includes a vibration bracket 2141 and a vibration motor 2142 fixed on the vibration bracket 2141, wherein at least one eccentric mass is symmetrically disposed at two ends of the vibration motor 2142. In this embodiment, the vibration motor 2142 includes two motors symmetrically arranged along the vertical central axis of the device body 21, and the motors are fixed in the vibration bracket 2141 by bolts, and one of the motors rotates forward and the other rotates backward during operation, so as to cancel out the horizontal exciting force.
In some embodiments, the sliding mechanism 218 includes a sliding slot and a sliding block disposed within the sliding slot, and the sliding block is coupled to the vibration mechanism 216.
In some embodiments, when the number of the eccentric mass blocks is two, the included angle of the eccentric mass blocks is adjustable, and the magnitude of the excitation force of the vibration mechanism 216 is adjusted by adjusting the included angle of the eccentric mass blocks, wherein the magnitude of the excitation force of each motor is adjusted within a range of 0-13 kN.
In some embodiments, the vibration time of the vibration mechanism 216 is adjustable between 0 minutes and 10 minutes.
In some embodiments, the vibration frequency of each motor is adjustable within a range of 0-60 Hz;
in some embodiments, the static compressive stress of the oscillating indenter 211 can be adjusted to a range of 0 to 800kPa
In some more preferred embodiments, control box 217 is coupled to sliding mechanism 218 and/or vibrating mechanism 216.
As can be seen from fig. 2 to 5, the oscillating ram adjustment mechanism 215 includes a cylinder provided at the top and an air compressor 22 (the arrangement of the air compressor 22 can be seen in fig. 1), wherein a piston member of the cylinder is connected with the oscillating ram. The cylinder and the air compressor are connected with the regulating valve through a pressure-resistant air pipe.
Fig. 6 is a schematic view of a connection structure between a test piece mold and a base in one embodiment of the vibration and rotation combined molding apparatus of the present invention. Fig. 7 is a schematic view of a connection structure between a test piece mold fixing member and a base in one embodiment of the vibration and rotation combined molding apparatus of the present invention.
As shown in fig. 6, and with reference to fig. 7 as necessary, the specimen mold 212 is fixedly coupled to the mold fixture mount 210 by a specimen mold fixture 219.
To facilitate handling, in this embodiment, specimen mold fixture 219 includes two arcuate members 2191, which are removably coupled to each other (e.g., spliced or otherwise provided with corresponding removable connectors) 2191.
When the arcuate members 2191 are connected, they may form a space to allow the trial mold 212 to pass through the space.
Of course, it is contemplated that in other embodiments, the number and shape configuration of the arcuate members 2191 may be configured according to the specifics of the respective embodiment, for example, according to the external shape configuration and ease of disassembly of the specimen mold 212.
In the present embodiment, the specimen die holder 219 and the die holder base 210 are connected by bolts. The specific structure can refer to fig. 8 and fig. 9, wherein fig. 8 is a schematic structural view of a base of the vibration and rotation combined forming device according to an embodiment of the present invention; fig. 9 is a schematic structural view of an arc-shaped part of the vibration and rotation combined forming device in one embodiment of the utility model.
Specifically, as shown in fig. 8, a first through hole 251 is provided on the base 213, and correspondingly, as shown in fig. 9, a second through hole 252 is provided at a corresponding position of the arc member 2191, and a connecting member penetrates through the first through hole 251 and the second through hole 252 to achieve a fixed connection between the test piece mold fixing member 219 and the mold fixing base 210, such as specifically, the first through hole 251 and the second through hole 252 are provided as bolt holes, and the connecting member is provided as a bolt, thereby achieving a fixed connection.
Fig. 10 is a schematic structural diagram of a test piece mold in an embodiment of the vibration and rotation combined forming device according to the present invention.
As shown in fig. 10, the specimen die 212 includes a specimen die test tube 2121 and a shoe 2122 movably connected to the specimen die test tube 2121.
In the present embodiment, the shoe 2122 is fixed to the die holder 210 by a test piece die fixing member, and specifically, for example, a through hole may be provided in the shoe 2122 to fix the shoe 2122.
The inner space of the test piece mold 2121 can be adapted according to the shape of the vibrating ram 211.
When the specimen mold cartridge 2121 is combined with the shoe 2122, the semi-enclosed space formed by it can be used to place a specimen, such as asphalt.
The operation of the vibration and rotation combined molding apparatus according to the present embodiment is specifically as follows:
in operation, the vibration mechanism 216 (in this embodiment, the vibration mechanism 216 is composed of the vibration bracket 2141 and 2 vibration motors 2142, although it is conceivable that, in some other embodiments, the number of the vibration motors 2142 may be set according to the specific situation of each embodiment) is controlled to be lifted by the lifting button of the control box 217, so that the height difference between the vibration pressure head 211 connected to the lower end of the vibration mechanism 216 and the mold fixing base 210 after being lifted is ensured to be greater than the height of the test piece mold 212, so as to facilitate the placement of the test piece mold 212.
Then, a vibration indenter 211 and a test piece mold 212 (in the technical solution of the present invention, the test piece mold 212 may be an optional standard mold for a rotary compactor, and in this embodiment, a standard mold for a rotary compactor is used)The specimen mold of (c) and the specimen mold 212 (containing the asphalt mixture) is fixed to the base 213 using the specimen mold fixture 219 and a connecting member such as a bolt.
Then, the vibration mechanism 216 is slowly descended through a descending button of the control box 217, so that the vibration pressure head 211 connected with the lower end of the vibration mechanism 216 is completely embedded into the test piece mold 212 after descending, and is tightly attached to the surface of the asphalt mixture in the test piece mold 212.
And then setting proper vibration frequency, static pressure stress and vibration time, and adjusting the nominal amplitude and the exciting force of the vibration motor. The vibrocompaction test is started by a vibration button of the control box 217.
The rotary compactor 23 is a downstream device of the device body 21, and automatic demolding of the specimen mold 212 is performed by a demolding module provided in the rotary compactor 23.
After the test piece is formed, the asphalt mixture as the formed test piece is ejected out by a pressure head in the rotary compaction instrument 23, namely, the automatic demoulding operation is completed, so that a large number of test piece moulds do not need to be prepared.
The test result obtained by the process shows that the test device is effective, the test efficiency is improved, and the device has a simple structure and is convenient to install and operate.
Example 2
In this embodiment, a vibratory rotary combined forming apparatus as shown in fig. 1 to 10 is used to perform vibratory rotary combined forming to simulate an on-site asphalt mixture compacting process. Referring to fig. 11, a flow chart of the vibration-rotation combined molding apparatus according to an embodiment of the present invention is shown in fig. 11.
As shown in fig. 11, the using process of the vibration and rotation combined forming device includes the following steps:
step A: adding asphalt mixture into the test piece mold;
and B: selecting a corresponding working condition mode to simulate the compaction process of the on-site asphalt mixture;
wherein the working condition modes comprise one or more of the following:
paving static pressure or paving vibration, initial pressing static pressure or initial pressing vibration, re-pressing static pressure or re-pressing vibration and final pressing static pressure.
Of course, in some preferred embodiments, the step B specifically includes the following steps:
step B1: simulating a paving static pressure and an initial pressure static pressure;
step B2: simulating the repressing vibration;
step B3: and simulating final hydrostatic pressure.
Alternatively, in some other preferred embodiments, the step B specifically includes the following steps:
step B4: simulating paving vibration;
step B5: simulating initial pressure static pressure;
step B6: simulating compound pressure vibration
Step B7: and simulating final hydrostatic pressure.
Example 3
In the present embodiment, the vibration and rotation combined forming device shown in fig. 1 to 10 is used for vibration and rotation combined forming to simulate the on-site asphalt mixture compacting process, and the working flow is shown in fig. 12. FIG. 12 is a schematic view showing a flow chart of the vibration and rotation combined forming device according to another embodiment of the present invention.
As shown in fig. 12, the using process of the vibration and rotation combined forming device includes the following steps:
adding asphalt mixture into the test piece mold;
selecting a corresponding working condition mode to simulate the compaction process of the on-site asphalt mixture;
wherein the working condition modes comprise one or more of the following:
paving static pressure or paving vibration, initial pressing static pressure or initial pressing vibration, re-pressing static pressure or re-pressing vibration and final pressing static pressure.
As can be seen from fig. 12, fig. 12 provides two modes of operation, but it is understood that the specific parameters or sequence involved in the operation can be adjusted by those skilled in the art according to the compaction process of the asphalt mixture to be actually simulated.
In addition, taking the first mode in fig. 12 as an example, when the first mode is selected, the vibration-rotation combination molding process specifically includes the following steps:
adding an asphalt mixture (in the scheme, the test piece is a mixed asphalt material) into a test piece mold;
firstly, carrying out rotary compaction for a plurality of times, simulating the processes of on-site paving static pressure and initial pressure static pressure, and adjusting corresponding parameters in the process such as: number of gyratory compaction a (e.g. 12), vertical pressure Pi(the vertical pressure is kPa) and/or the rotational speed Ni(the dimension of the rotating speed is r/min);
then, a period of vibratory compaction (for example, b seconds, b may be any positive real number) is performed to simulate an on-site recompression vibratory process, in which corresponding parameters may be adjusted, for example: excitation force Qj(laser)Vibration force dimension kN), static compressive stress Lj(the static compressive stress is kPa), and the vibration time Tj(dimension of vibration time is S) and vibration frequency Sj(the vibration frequency is in Hz) and/or the nominal amplitude Aj(nominal amplitude dimension is mm);
finally, the asphalt mixture after the vibration compaction is placed in a PINE rotary compaction instrument for rotary compaction forming (test piece height control), a field final pressure static pressure process is simulated, and in the process, corresponding parameters such as: number of gyratory compaction c times, vertical pressure Pk(the vertical pressure is kPa) and/or the rotational speed Nk(the dimension of the rotation speed is r/min).
Taking the second mode in fig. 12 as an example, when the second mode is selected, the vibration-rotation combined molding process specifically includes the following steps:
adding an asphalt mixture (in the scheme, the test piece is a mixed asphalt material) into a test piece mold;
vibratory compaction is performed for a period of time (e.g., d seconds, d may be any positive real number) to simulate paving vibration, and corresponding parameters may be adjusted during the process, such as: excitation force Ql(the dimension of the excitation force is kN) and the static compressive stress Ll(the static compressive stress is kPa), and the vibration time Tl(dimension of vibration time is S) and vibration frequency Sl(the vibration frequency is in Hz) and/or the nominal amplitude Al(nominal amplitude dimension is mm);
several gyratory compaction (e.g. e times, e being any positive integer, e.g. 3-4 times) is then performed, simulating an incipient-pressure hydrostatic process, during which corresponding parameters may be adjusted, such as: number of times of compaction test by rotation, vertical pressure Pm(the vertical pressure is kPa) and/or the rotational speed Nm(the dimension of the rotating speed is r/min);
then, vibrating compaction is carried out for a period of time, a field repressing vibration process is simulated, and corresponding parameters such as: excitation force Qn(the dimension of the excitation force is kN) and the static compressive stress Ln(the static compressive stress is kPa), and the vibration time Tn(dimension of vibration time is S) and vibration frequency Sn(the vibration frequency is in Hz) and/or the nominal amplitude An(nominal amplitude is nominally in mm);
finally, the asphalt mixture after the vibration compaction is placed in a PINE rotary compaction instrument for rotary compaction forming (test piece height control), a field final pressure static pressure process is simulated, and in the process, corresponding parameters such as: the number of times of rotary compaction is g (g can be any positive integer), and the vertical pressure P iso(the vertical pressure is kPa) and/or the rotational speed No(the dimension of the rotation speed is r/min).
The main parameters that consider the vibrating equipment to influence the compacting effect are: exciting force, vibration frequency, nominal amplitude and vibration time, road roller advancing speed isoparametric should also be considered in the on-the-spot vibrocompaction, therefore, the simulation has set up following experiment and has verified:
in a paving and compacting site, a vibratory roller compacts a road surface by utilizing the self gravity and the impact force generated by vibration, is mainly used for re-compacting an asphalt surface layer, and has the vibration frequency within the range of 33-50Hz according to the American regulation. The vibration frequency is preferably 35-50Hz and the nominal amplitude is preferably 0.3-0.8mm in the technical Specification for constructing asphalt road surfaces of roads (JTG F40-2004) in China. Domestic research on vibratory rollers shows that: within the frequency range of 25-50Hz, the change of the compaction effect is relatively stable; while the compaction effect changes more significantly when the nominal amplitude is increased by 1 fold. Nominal amplitude a of a vibratory roller0(dimension m) is independent of the external operating conditions, and the size can be calculated according to the following formula:
A0=Me/Md (1)
Me=m0×r0 (2)
F0=Meω2 (3)
ω=2πf (4)
in the formula, MeStatic eccentricity of vibration exciterMoment (dimension kg x m); mdRepresenting the vibration mass (dimension is kg) of the road roller; m is0Represents the mass of the eccentric block (dimension is kg); r is0Represents the eccentricity (dimension m) of the eccentric block; f0Represents an excitation force (dimension N); ω represents the rotation speed (in rad/s); f denotes the frequency (dimension in Hz).
The actual measurement shows that the magnitude of the static compressive stress has great influence on the vibration compaction. The static pressure stress is generated by the combination of the pressure of the cylinder and the self weight of the vibration system, and the magnitude of the static pressure stress can be adjusted by air pressure. The two motors synchronously rotate in opposite directions to offset the horizontal exciting force, and finally the vertical exciting force is ensured. The exciting force can also be adjusted by the mass plate in the motor. The control box is provided with timing, time delay, frequency modulation and other devices. In order to simulate the compaction process in the construction site, the fixed frequency is 48Hz, the double-motor exciting force is 26kN, the static pressure stress of the vibration pressure head is 10kN (corresponding to 690kPa), and the nominal amplitude is 0.3 mm.
The test piece of the forming test is made of SMA13 asphalt mixture, and in order to ensure the comparability of the test pieces in different forming modes, the target porosity of the test pieces subjected to rotary compaction and combined compaction is close to the porosity of the on-site core sample, and the porosity of the test pieces subjected to rotary compaction and combined compaction is controlled by 7 +/-0.5 percent in the example.
Pure rotary compaction is carried out by adopting a U.S. PINE rotary compactor, selecting a test die with the diameter of 150mm, and forming the die with the standard compaction height of 115 mm. Through three groups of rotary compaction test piece parallel tests, after recording the height of the compaction process and measuring the porosity, the average rotation time required for reaching the target porosity of the test piece is determined to be 40 times, and the mass of a test piece with the height of 115mm of a single test piece is measured to be 4.8 kg. The test piece a was formed by pure rotational molding.
Three groups of vibration time for combined compaction are selected: 20s, 40s and 60s, namely B, C and D test pieces corresponding to the test pieces in tables 1 and 2, are formed by combining vibration and rotation of the vibration and rotation combined forming device 1. And determining the corresponding rotation times of the target porosity test piece according to the average value of at least 3 groups of parallel test pieces.
As can be seen by coring on site and combining with site construction experience, the porosity of the corresponding core sample after paving is 13%, and the porosity of the corresponding core sample after initial pressing is 11%. Referring to the change process of the porosity of the test piece in the rotary compaction process, the paving static pressure (equivalent to 8-9 times of rotary compaction of the test piece) and the first initial static pressure (equivalent to 3-4 times of rotary compaction of the test piece) can be presumed to be equivalent to 12 times of rotary compaction. In the vibration and rotation combined compaction forming test B, C and the test piece D in the example, after the simulated paving static pressure and the initial compaction static pressure are carried out for 12 times by adopting the rotation compaction, vibration compaction is carried out respectively for 20s, 40s and 60s so as to simulate the re-compaction vibration, and finally the rotation compaction is carried out (the height of the test piece is controlled to be 115mm) so as to simulate the final compaction static pressure.
Finally, comparing the porosity and the porosity size distribution of the transverse section and the radial section of the indoor forming test piece and the field core sample, and verifying that the combined forming method is closer to the field core sample in the gap characteristic.
The specific porosity test results are shown in table 1 below:
TABLE 1 detailed table of indoor formed test piece
Sampling and calculating the field samples (with the height of 40mm) with the top and the bottom cut off by 5mm respectively; for the room test specimens (height 115mm) which were referenced to the existing research literature, 20mm samples were taken from the top and bottom, and the results are shown in Table 2 below:
TABLE 2 void fraction analysis Table
As can be seen from Table 2, the mean value, the standard deviation and the dispersion coefficient are compared, and the test piece C formed by combining the vibration and the rotation is closer to the field core drilling void ratio result than the test piece A formed by pure rotation. The results show that the combined forming method adopted by the utility model can better simulate the actual compaction situation on site compared with pure rotary compaction.
In addition, the indoor vibration rotation combination molding method can optimize the compaction degree of the asphalt mixture test piece by adjusting parameters such as exciting force, static compressive stress, vibration time, vibration frequency and nominal amplitude, and can guide on-site pavement compaction operation.
While specific embodiments of the utility model have been described above, it will be appreciated by those skilled in the art that this is by way of example only, and that the scope of the utility model is defined by the appended claims. Various changes and modifications to these embodiments may be made by those skilled in the art without departing from the spirit and scope of the utility model, and these changes and modifications are within the scope of the utility model.
Claims (7)
1. A vibratory rotary composite forming apparatus for simulating in situ road compaction, said vibratory rotary composite forming apparatus comprising:
a test piece mold;
the device comprises a device body, wherein a vibration pressure head and a test piece die matched with the vibration pressure head are arranged on the device body, the test piece die is provided with an internal space matched with the shape of the vibration pressure head, and the internal space of the test piece die is used for placing a test piece;
and the rotary compaction instrument is provided with an accommodating space which can be used for accommodating the test piece mold in a matching manner.
2. The vibrating-rotating combined forming device as claimed in claim 1, wherein a bottom support is arranged at the bottom of the test piece mold;
and/or scales are engraved on the outer wall of the vibration pressure head, so that the height of the test piece in the test piece die in the vibration compaction process is displayed in real time.
3. The vibro-rotary composite molding apparatus according to claim 1 or 2, characterized in that said apparatus body comprises:
the device comprises a device base, a test piece die and a test piece, wherein a die fixing base is arranged on the device base;
the wide-surface machine body upright columns are symmetrically arranged on two sides of the die fixing base;
the vibration mechanism is connected with the wide-face machine body upright column in a sliding manner through a sliding mechanism and is connected with the vibration pressure head;
the vibration pressure head adjusting mechanism is connected with the vibration pressure head so as to adjust the static pressure stress of the vibration pressure head;
wherein, the lower extreme of vibration pressure head is located along the axial direction of device body to the test piece mould.
4. The device according to claim 3, wherein the vibrating mechanism comprises a vibrating frame and a vibrating motor fixed on the vibrating frame, wherein at least one eccentric mass block is symmetrically arranged at two ends of the vibrating motor;
and/or the test piece mold is fixed on the mold fixing base through a test piece mold fixing piece;
and/or the base is fixed with the ground through bolts;
and/or, the sliding mechanism comprises a sliding groove and a sliding block arranged in the sliding groove, and the sliding block is connected with the vibration mechanism.
5. The vibratory rotary composite molding apparatus of claim 4 wherein the angle of the eccentric masses is adjustable when the eccentric masses are two;
and/or the adjustable vibration time interval of the vibration mechanism is 0-10 minutes;
and/or the adjustable range of the motor vibration frequency of the vibration mechanism is 0-60 Hz;
and/or the static pressure stress adjustable interval of the vibration pressure head is 0-800 kPa;
and/or the test piece die fixing piece comprises at least one arc-shaped piece, and the bottom support is fixed on the die fixing base through a bolt by the arc-shaped piece;
and/or the base is fixed with the ground through bolts;
and/or the vibration motor comprises two motors which are symmetrically arranged along a vertical central axis of the device body, and the adjusting range of the exciting force of each motor is 0-13 kN.
6. The vibro-rotary composite molding apparatus according to claim 3, characterized in that said apparatus body further comprises a control box connected with a sliding mechanism and/or a vibrating mechanism;
and/or the vibration pressure head adjusting mechanism comprises an air cylinder and an air compressor, wherein a piston piece of the air cylinder is connected with the vibration pressure head.
7. A vibratory rotary composite molding apparatus as set forth in claim 6 wherein said control box is an electrical control box;
and/or the air cylinder and the air compressor are connected with the regulating valve through a pressure-resistant air pipe.
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CN115179394A (en) * | 2022-07-21 | 2022-10-14 | 深圳市市政工程总公司 | Cement stabilization solid waste aggregate base layer vibration compaction forming equipment |
CN115179394B (en) * | 2022-07-21 | 2024-04-05 | 深圳市政集团有限公司 | Operation method of vibration compaction forming equipment for cement stabilized solid waste aggregate base layer |
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