GB2378766A - Apparatus for testing compaction of material samples - Google Patents
Apparatus for testing compaction of material samples Download PDFInfo
- Publication number
- GB2378766A GB2378766A GB0119794A GB0119794A GB2378766A GB 2378766 A GB2378766 A GB 2378766A GB 0119794 A GB0119794 A GB 0119794A GB 0119794 A GB0119794 A GB 0119794A GB 2378766 A GB2378766 A GB 2378766A
- Authority
- GB
- United Kingdom
- Prior art keywords
- mould
- longitudinal axis
- compression
- axis
- holding
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/42—Road-making materials
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/286—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q involving mechanical work, e.g. chopping, disintegrating, compacting, homogenising
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0001—Type of application of the stress
- G01N2203/0005—Repeated or cyclic
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0014—Type of force applied
- G01N2203/0016—Tensile or compressive
- G01N2203/0019—Compressive
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0014—Type of force applied
- G01N2203/0025—Shearing
Abstract
A compactor apparatus, particularly for the testing of the compactability of paving material, comprises a cylindrical mould 5 for receiving a sample of the material and a compression platen 11 for engaging the material in the mould. The mould 5 is supported with its longitudinal axis tilted relative to the axis along which compression is applied by the platen 11 and is rotated about this tilted longitudinal axis, the tilted longitudinal axis not itself moving. The angle of tilt is set by a motor 26.
Description
<Desc/Clms Page number 1>
Method and Apparatus for Compacting Material Samples Field of the Invention The present invention concerns improvements in and relating to compacting of material samples such as soil or paving material. The method and apparatus are particularly suitable for testing Tarmacadam/asphalt or the like to ensure that it is of the right consistency to be compacted reliably and consistently to a required degree for use on roads and other constructions.
Background to the Invention When laying a road surface with Tarmacadam or asphalt the quality and consistency of the road surface is dependent upon a number of factors, of which one of the most important is the consistency of the asphalt/Tarmacadam. To substantially eliminate this variable to ensure that the road surface can be prepared, as far as possible to a high and consistent standard, it is necessary to ensure that the composition to be used to form the road surface is of a consistency that ensures compaction to a known standardised level in response to a standardised level of compaction force that is normally applied in use by the road laying roller engines.
The most direct way to ensure that the Tarmacadam/asphalt to be used is of consistent compactability is, of course, to sample it prior to use and test it for compaction under conditions that simulate the nature of compaction that occurs in use under the roller of the road laying roller engines. Here the conventional test as detailed in, for example, US 5,323, 655 and US 5,606, 133 employs a compactor assembly comprising a frame supporting a hydraulically or pneumatically driven ram above a cylindrical mould that holds the sample for compaction and to extend into the mould, the mould being tilted at a predetermined angle, normally one and a half degrees, relative to the longitudinal axis of the ram, to compact the sample in the mould to a required extent. The tilt mimics the angle of the force applied by the curving face of the road laying roller. Further, in order to best mimic the conditions that apply in use, where a compression wave is formed at the front of the road laying roller when compacting the Tarmacadam/asphalt, the conventional compaction rig incorporates a rotary mounting assembly mounting the tilted mould to the frame so that the mould can gyrate with the one and a half degree angle of tilt about the axis
<Desc/Clms Page number 2>
of compression. In US 5,323, 655 the longitudinal axis at the lower end of the mould orbits around the axis of compression and in US 5,606, 133 the upper end orbits the axis of compression.
A major problem with many existing such compactors is that they have an inherently high number of moving parts and are complex and relatively costly to manufacture and service. It is a general objective of the present invention to address this problem.
Summary of Invention According to a first aspect of the present invention there is provided a compactor apparatus comprising: a cylindrical mould having a central longitudinal axis and a first open end for receiving material to be compacted ; a ram mounted for movement into the first open end of said mould for applying a compressive force to the material in the mould along an axis of compression to compact the material ; and a base positioned to support a second end of said mould as the axial compressive force is applied thereto; the base including means for holding the mould in a tilted operative position in which the central longitudinal axis of the mould is angularly offset from the axis of compression and wherein the mould rotates about its central longitudinal axis but the central longitudinal axis of the mould is held in position during operation and does not move.
Suitably the compactor apparatus has a support frame to which the ram is mounted and from which the base is supported and wherein the means for holding the mould in the tilted operative position is fixed to the support frame whereby it is selectively adjustable in tilt relative to the longitudinal axis of the mould, but otherwise immobilised on the framework.
Suitably the selectively tilt adjustable means for holding the mould in the tilted operative position comprises a pair of pivotal support mountings to cradle the mould between them, the pivotal support mountings being fixed to the framework.
<Desc/Clms Page number 3>
Preferably the means for holding the mould further comprises motorised actuator means for moving the mould to the tilted operative position.
Preferably the apparatus further comprises resilient biasing means to antagonise the motorised actuator means tilting the mould suitably to restore the mould to an initial neutral position in which the longitudinal axis is co-linear with the compression axis.
Brief Description of the Drawings A preferred embodiment of the present invention will now be more particularly described, by way of example, with reference to the accompanying drawings wherein: ", "'" Figure 1 is a frontal perspective view of the preferred embodiment of the compactor apparatus with mould removed and compression ram raised;
Figure 2 is a lateral perspective view with the mould in place;
Figure 3 is a composite diagram of the apparatus in side elevation showing the upper and lower parts of the rig, and the mould and mould mounting assembly in longitudinal sectional view as seen from the side;
Figure 4 is a view similar to figure 3 but is viewed from the front of the apparatus and with the ram lowered into the mould ;
Figure 5 is a plan view from above of the lower part of the rig;
Figure 6 is a plan view from above of the upper part of the rig; and
Figures 7A to 7E are, respectively, a schematic diagram illustrating the manner of rotation of the mould in the compactor apparatus of the present invention;
<Desc/Clms Page number 4>
schematic diagrams of the motion of a mould in a conventional prior art compactor (Figure 7B first position-Figure 7C second position); and a schematic diagram of the motion of the mould of the present invention (Figure 7D first position-Figure 7E second position).
Description of the Preferred Embodiment Referring to figures 1 to 6, the compactor rig assembly comprises a support frame 1 having a gantry 2 that supports the compression ram 3. The gantry 2 holds the compression ram 3 above a sample support table 4 so that the ram 3 may reciprocate along what is suitably a vertical axis over a substantially circular cylindrical sample holding pot/mould 5 that is indirectly supported by the table 4.
The mould 5 is a cylinder open at both ends but having a bottom platen 35 positioned therein to serve as a floor to the mould 5 in use.
The gantry 2 of the illustrated embodiment comprises four tubular support columns 6a-d standing as substantially vertical legs from the base 1 of the frame 1 and in a rectangular configuration as viewed in plan. The tops of the support columns 6ad are linked together and rigidly held in the rectangular configuration by a rectangular top plate 7 and on to which is mounted a cylinder 8 of the compression ram 3, with a shaft 9 of the ram 3 extending vertically down through an aperture in the top plate 7.
The shaft 9 of the ram 3 does not extend into the mould 5 itself, instead it acts on a connecting rod 10 to which is fixed a compression/upper platen 11 that slides in and out of the mould 5, in use, to compress the sample 16. The compression head assembly comprising the connecting rod 10 with the compression platen 11 may be decoupled from the shaft 9 of the ram 3 when not in operation, so that the compression head assembly 10,11 may be displaced, suitably backwardly to a position 11'away from overlying the mould 5 (see Figure 6). This facilitates mounting or removal of the mould 5 and/or filling/emptying of the mould 5 while the mould 5 remains in situ on the rig.
<Desc/Clms Page number 5>
The compression head assembly 10,11 is mounted in a carriage assembly 12 that is configured to move vertically, being shaped to seat closely within the rectangular frame defined by the columns 6a - d and having rollers 15 to run up and down along inner faces of the columns 6a-d. Figure 4 shows the compression head assembly 10,11 and the carriage assembly 12 in which it is mounted moved to a lowered position with the compression platen 11 extending into the mould 5, compressing a sample 16 in the mould 5.
The carriage assembly 12 further has inbuilt horizontal tracks 14 for rearward displacement of the head assembly 10,11 as briefly mentioned above with respect to Figure 6. Inner rollers 13 of the carriage assembly 12 run along these horizontal tracks 14.
The sample support table 4 indirectly supports the sample holding mould 5. As can be seen from Figures 1-4, the mould 5 is supportively seated with its lower end in a support collar 19 that is in turn seated with an outer support collar 20 wherein the outer support collar 20 is, in turn, pivotally mounted as a cradle between support pillars 17 (see Figure 4).
The outer support collar 20 is pivoted to the support pillars 17 by respective pivot pins 18, one on each side, whereby the mould 5 mounted to the collar 19 and outer collar 20 is able to tilt slightly in a direction towards the rear of the apparatus. Indeed, the mould 5 would be permitted to tilt fore or aft but is constrained to have a very limited degree of tilting movement by the respective front and rear brackets 23 mounted to the outside of the outer collar 20 but not rotationally coupled to the collar 20.
The front bracket 23 rests upon a front stop bolt 24 to hold the mould 5 in a neutral upright stance when the apparatus is not operating. Resilient biasing means may be provided (not illustrated) to bias the tilting assembly (mould 5 and inner 19 and outer 20 collars) to the neutral position.
The rear bracket 23 is powered by a motorised actuator 26 to be moved to a selective tilted operative position-which is suitably the approximately one and a half degree angle of tilt that is generally required for standard compaction tests.
<Desc/Clms Page number 6>
The motorised actuator 26 may comprise an electric stepper motor or a hydraulically or pneumatically activated piston. The actuator is suitably selectively adjustable and may, for example, be used in combination with selective adjustable stop means 25 to allow the user to adjust the angle of tilt as necessary for any particular task.
As can best be seen from Figure 3, the bottom platen 35 which forms the floor of the mould 5 in use is, in turn, supported on a plinth 27 that is coupled to a piston rod 32.
The piston rod 32 is mounted in a cylinder fastened to the frame whereby elevation of the piston rod 32 will raise the plinth 27 and thereby raise the bottom platen 35 for ejection of the sample following the test cycle.
In use of the apparatus a motor 33 which may suitably be an electric motor, is driven to move a drive band 37 (see Figure 5) to drive the inner collar 19 to rotate. Since the outer collar 19 is keyed to the bottom end of the mould 5 by an interlocking pin 22, the mould 5 will rotate with the inner collar 19.
Tapered bearings 28 between the outer collar 20 and the inner collar 19 allow the inner collar 19 to rotate within the outer collar 20 while accommodating the loads that are applied to the mould 5 in use. The support plinth 27 is also stablised relative to the cylinder for the piston rod 32 by means of tapered bearings 29 and provision is also made at the upper end of the apparatus to dampen operative stresses and strains by provision of thrust bearings 31 between the compression head 10,11 and the carriage assembly 12.
The mould 5 is set in rotating motion once the sample 16 is in place and the compression (upper) platen 11 lowered into the mould 5 as illustrated in Figure 4.
Referring to Figure 7A, it will be appreciated that the mould 5 rotates about its own longitudinal axis 40 while tilted at the selected angle to the axis of compression 50.
In the illustrated embodiment the axis of compression 50 is a vertical axis.
Each of the upper 11 and lower 35 platens rotates about its own vertical axis and all three components, the mould 5 and the platens 11,35 rotate in the same direction
<Desc/Clms Page number 7>
and at the same speed. The mould 5 does not orbit the axis of compression 50, it rotates about its longitudinal axis but its longitudinal axis does not move.
As can be seen from Figures 7B and 7C, in the conventional arrangement of compactor apparatus the mould orbits the axis of compression at the selected angle of incline.
It will be appreciated on comparison of Figures 7B and 7C illustrating the prior art motion against Figures 7D and 7E illustrating the motion in the present invention that the compression pattern achieved by the configuration of the present invention achieves substantially the same effect as in the prior art configuration. Extensive trials have demonstrated that the results with the apparatus configured as in the present invention is as accurate and reliable as the prior art configuration and, furthermore, through having less moving components has greater long term reliability. The apparatus of the present invention is substantially less complex and cheaper to assemble and simpler to maintain than the prior art apparatus while achieving the required results and represents an important advance in compactor design.
Claims (7)
- Claims 1. A compactor apparatus comprising: a cylindrical mould having a central longitudinal axis and a first open end for receiving material to be compacted; a ram mounted for movement into the first open end of said mould for applying a compressive force to the material in the mould along an axis of compression to compact the material ; and a base positioned to support a second end of said mould as the axial compressive force is applied thereto; the base including means for holding the mould in a tilted operative position in which the central longitudinal axis of the mould is angularly offset from the axis of compression and wherein the mould rotates about its central longitudinal axis but the central longitudinal axis of the mould is held in position during operation anddoes not move.
- 2. An apparatus as claimed in claim 1, wherein the compactor apparatus has a support frame to which the ram is mounted and from which the base is supported and wherein the means for holding the mould in the tilted operative position is fixed to the support frame whereby it is selectively adjustable in tilt relative to the longitudinal axis of the mould, but otherwise immobilised on the framework
- 3. An apparatus as claimed in claim 2, wherein the selectively tilt adjustable means for holding the mould in the tilted operative position comprises a pair of pivotal support mountings to cradle the mould between them, the pivotal support mountings being fixed to the framework.
- 4. An apparatus as claimed in claim 1,2 or 3, wherein the means for holding the mould further comprises motorised actuator means for moving the mould to the tilted operative position.
- 5. An apparatus as claimed in claim 4, wherein the apparatus further comprises resilient biasing means to antagonise the motorised actuator means tilting the mould.<Desc/Clms Page number 9>
- 6. A method of compaction testing paving materials and which comprises placing a sample of material to be tested into a mould, tilting the mould to a predetermined test angle relative to a compression axis on which the sample is compressed, and rotating the mould about its own longitudinal axis while maintaining the mould in a fixed position relative to the compression axis.
- 7. A compactor apparatus as hereinbefore described with reference to figures 1 to 6, 7A, 7B, 7D or 7E.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0119794A GB2378766A (en) | 2001-08-14 | 2001-08-14 | Apparatus for testing compaction of material samples |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0119794A GB2378766A (en) | 2001-08-14 | 2001-08-14 | Apparatus for testing compaction of material samples |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB0119794D0 GB0119794D0 (en) | 2001-10-03 |
| GB2378766A true GB2378766A (en) | 2003-02-19 |
Family
ID=9920362
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0119794A Withdrawn GB2378766A (en) | 2001-08-14 | 2001-08-14 | Apparatus for testing compaction of material samples |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2378766A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2477432A (en) * | 2011-02-01 | 2011-08-03 | Mecpart S R L | Roller compactor integrated to a wheel track machine for laboratory tests on bituminous mixes |
| CN101382536B (en) * | 2008-10-10 | 2012-07-25 | 哈尔滨工业大学 | On-site evaluating apparatus for loosing degree for asphalt pavement |
| ES2394801R1 (en) * | 2011-02-18 | 2013-08-08 | Univ Burgos | PROCEDURE AND DEVICE FOR COMPACTION OF PRISMATIC TESTS FOR THE CHARACTERIZATION OF GRANULAR MATERIALS TREATED WITH HYDRAULIC CONGLOMERANTS FOR USE ON ROADS. |
| CN103994936A (en) * | 2014-06-03 | 2014-08-20 | 北京科技大学 | Horizontal high-tonnage energy-saving fatigue experiment device |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5275056A (en) * | 1992-10-20 | 1994-01-04 | Rainhart Co. | Gyratory shear material compacting device |
| US5824913A (en) * | 1997-01-10 | 1998-10-20 | Pine Instrument Company | Portable gyratory compactor and extruder with a single pivot and two gyration actuators |
| WO2001086251A1 (en) * | 2000-05-12 | 2001-11-15 | Antti Paakkinen | Method and apparatus for measuring packing properties of soil masses and other similar masses |
-
2001
- 2001-08-14 GB GB0119794A patent/GB2378766A/en not_active Withdrawn
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5275056A (en) * | 1992-10-20 | 1994-01-04 | Rainhart Co. | Gyratory shear material compacting device |
| US5824913A (en) * | 1997-01-10 | 1998-10-20 | Pine Instrument Company | Portable gyratory compactor and extruder with a single pivot and two gyration actuators |
| WO2001086251A1 (en) * | 2000-05-12 | 2001-11-15 | Antti Paakkinen | Method and apparatus for measuring packing properties of soil masses and other similar masses |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101382536B (en) * | 2008-10-10 | 2012-07-25 | 哈尔滨工业大学 | On-site evaluating apparatus for loosing degree for asphalt pavement |
| GB2477432A (en) * | 2011-02-01 | 2011-08-03 | Mecpart S R L | Roller compactor integrated to a wheel track machine for laboratory tests on bituminous mixes |
| ES2394801R1 (en) * | 2011-02-18 | 2013-08-08 | Univ Burgos | PROCEDURE AND DEVICE FOR COMPACTION OF PRISMATIC TESTS FOR THE CHARACTERIZATION OF GRANULAR MATERIALS TREATED WITH HYDRAULIC CONGLOMERANTS FOR USE ON ROADS. |
| CN103994936A (en) * | 2014-06-03 | 2014-08-20 | 北京科技大学 | Horizontal high-tonnage energy-saving fatigue experiment device |
Also Published As
| Publication number | Publication date |
|---|---|
| GB0119794D0 (en) | 2001-10-03 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| COOA | Change in applicant's name or ownership of the application | ||
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |