A kind of method of testing that is suitable for water conservancy project concrete anti-abrasion performance
The present invention relates to the anti-impact mill technology of water conservancy project, be particularly useful for the test of the indoor impact-resisting wear-resisting of concrete for hydraulic structure, what be applicable to that traction load crosses water buildings to concrete for hydraulic structure rushes mill experimental study.
In existing < < concrete for hydraulic structure testing regulations > > SL352-2006 and DL/T5150-2001, all there is the anti-impact mill test method of cement concrete, wherein one is steel ball method under water, in the method, mainly stipulated following parameter, the one, the grating of steel ball and size under water; The 2nd, stipulated the rotating speed of anti-impact grinding machine; The 3rd, the time of punching mill.Therefore in Practical Project, the sandstone containing in high-velocity flow, is mainly that Rolling Stone is the most serious to concrete punching mill, and very few to large particle diameter steel ball volume in current specifications, impact punching mill test effect; Secondly, the steel ball in the method for steel ball under water in current specifications is smooth ball, steel ball number 10,35,25; Diameter is respectively Φ 25.4 ± 0.1; Φ 19.1 ± 0.1; Φ 12.7 ± 0.1.This is not inconsistent with the multangular shape of actual Rolling Stone yet, must affect test effect, and larger with actual conditions gap.
The inventive method has changed steel ball grating and size shape under water, mainly contains 2 points: the one, in conjunction with the actual conditions of traction load grain composition, adjusted the grating of punching mill matter steel ball, i.e. and the quantity of steel ball and particle diameter ratio, makes it more to meet engineering actual conditions.The 2nd, the mill matter of rushing in current specifications is smooth sphere, and traction load in Practical Project is gravel or cobble, conventionally there are corner angle, this test method is cut into circular hexahedron by round steel ball, make it to have there are corner angle, more realistic, the to obtain Guiding Practice of science data accurately, has application and popularization value.
Summary of the invention
Order of the present invention is: for the method for testing of concrete for hydraulic structure anti-impact mill performance, changed steel ball grating under water, and will make smooth sphere be cut into circular hexahedron, and more realistic, realized design object.
The object of the present invention is achieved like this: a kind of method of testing that is suitable for water conservancy project concrete anti-abrasion performance, implement step by step:
Step 1 test specimen and rush grinding media preparation:
A, aggregate particle diameter≤40mm, three test specimens are one group, during moulding, concreting, in circular die trial, and are positioned over to bumper, vibrations density 20s, the demoulding after 24h, and be positioned in standard curing room, to stipulating the length of time;
In B, test specimen water, soak 48-52h, wipe moisture content, weigh the weight of each test specimen;
C, rush grinding media grating: 25 of the steel balls that diameter is 12.7mm, the circular hexahedron steel ball of well cutting is respectively: diameter 19.1mm, 35 of quantity; Diameter 25.4mm, 17 of quantity; Diameter 30.0mm, 8 of quantity;
D, hexahedron steel ball are processed again: by the steel ball of diameter 19.1mm, 25.4mm, 30.0mm, the excision take steel ball size as 5% respectively, must be with the hexahedron steel ball of corner angle;
Step 2 instrumentation:
1) adjusting paddle is 33-45mm apart from the distance of test specimen;
2) that in steel cylinder, puts into grating rushes grinding media steel ball in test specimen surface, and add water to the water surface and exceed test specimen surface 162-168mm, start, under 1200 revs/min of conditions, stir punching mill, time 72h, takes out the test specimen cleaning and wiping part of anhydrating, weigh the weight of each test specimen, wherein, every 24h, in steel cylinder, add water, keep former height of water level.
Described method of testing, is fixed in the steel cylinder 1 on base 5 paddle 2 is installed, and is evenly equipped with small ball and hexahedron steel ball 3 between paddle 2 and concrete sample 4, wherein in the bottom of concrete sample 4, spacer bar 9 is set; The osculum 6 that is distributed on concrete sample 4 bottoms is communicated with the osculum 6 on base 5, and the lower end of its osculum 6 is installed with draining valve 7; Sealed rubber packing ring 10 and fastening bolt are set on the bottom of steel cylinder 1 and base 5.
Mechanism of the present invention and effect: research shows, when thering are sharp keen corner angle and suitably when the abrasive particle of the angle of attack and material surface generation relative motion, will as cutter, to material, cut and form smear metal, under the same conditions, while being all 90 ° of angle of shocks, large 4 times than the wearing and tearing of circular abrasive particle of polygon abrasive particles, the present invention has improved the pattern of larger three grades of punching mill steel balls, makes it to become circular hexahedron; Meanwhile, according to mountain area detrusion matter particle size and grating situation, changed the grating of punching mill steel ball, the situation of the actual punching mill of more approaching test, shows technical progress.
Accompanying drawing explanation
Below in conjunction with accompanying drawing, the invention will be further described.
Accompanying drawing 1 for the present invention rush mill instrument structural representation:
As shown in the figure: 1-steel cylinder, 2-paddle, 3-small ball and circular hexahedron, 4-concrete sample, 5-base, 6-osculum, 7-draining valve, 8-water, 9-reinforcing bar, 10-rubber washer.
Below in conjunction with embodiment, be described further.
One, the design main points of this method
1) in conjunction with the actual conditions of traction load grain composition, adjusted the grating of punching mill matter steel ball, the quantity of steel ball and particle diameter ratio more meet engineering actual conditions.
2) steel ball number of punching mill matter and particle diameter require to see the following form 1; By orthogonal above diameter 20mm steel ball six faces, by 5% of steel ball size, be cut into plane, make steel ball become circular hexahedron, make it to have there are corner angle, more tally with the actual situation.
Steel ball number in this test method of table 1 and particle diameter requirement
|Steel ball number
Two, the contrast of this method of testing and current specifications test method
In order to verify the effect to anti-impact mill method of testing of the present invention, carry out altogether the contrast of 5 groups of existing anti-impact mills of concrete test, in Table 2.
Table 2 anti-impact mill test method of the present invention and current specifications comparison of test results
From above test result, find out, this method is for the concrete of different gradation, and its rate of wear is doubled, and abrasive effect significantly improves, and better reacts the abrasion condition in Practical Project.
Three, the concrete operations of method
1) prepare anti-impact grinding concrete test specimen, permission aggregate size is 40mm, and test is take three test specimens as one group, during moulding, concreting, in circular die trial, and is positioned over to bumper, vibrations density 20s, the demoulding after 24 hours, and be positioned in standard curing room, to stipulating the length of time.
2) before test, test specimen need at least soak 48h in water.
3) while testing, take out test specimen, wipe surperficial moisture content, take the weight of each test specimen.
4) on base plate, pad the reinforcing bar of two φ 6mm, the concrete sample having weighed is placed on reinforcing bar, and makes concrete surface perpendicular to rotating shaft, put steel cylinder, the bolt of be tightened steel cylinder and base, makes its sealing.
5) paddle is arranged in rotating shaft, paddle bottom is 38mm apart from test specimen surface, and the position of adjusting steel cylinder and base makes rotating shaft centering.
6) in steel cylinder, put into 25 of diameter 12.7mm steel balls, the circular hexahedron punching mill steel ball of well cutting is respectively: diameter 19.1mm, 35 of quantity; Diameter 25.4mm, 17 of quantity; Diameter 30.0mm, 8 of quantity; Be positioned over test specimen surface, and add water to the water surface and exceed test specimen surface 165mm; Wherein hexahedron steel ball is processed again: by the steel ball of diameter 19.1mm, 25.4mm, 30.0mm, the excision take steel ball size as 5% respectively, must be with the hexahedron steel ball of corner angle.
7) confirm that rotating shaft rotating speed is after 1200rpm, start.
8), every 24h, in steel cylinder, add 2 water to former height of water level.
9) add up punching mill 72h, take out test specimen, clean up, wipe surperficial moisture content, take the weight of each test specimen, and carry out the calculating of anti-impact mill intensity with the front each test specimen weight of test.
Four, the instrument of method of testing explanation:
Be fixed in the steel cylinder on base paddle is installed, between paddle and concrete sample, be evenly equipped with small ball and hexahedron steel ball, wherein in the bottom of concrete sample, spacer bar is set; The osculum that is distributed on concrete sample bottom is communicated with the osculum on base, and the lower end of its osculum is installed with draining valve; On the bottom of steel cylinder and base, sealed rubber packing ring and fastening bolt are set.