WO1986001294A1 - Method of iota situ) testing concrete for quality, and means for implementing the method - Google Patents

Method of iota situ) testing concrete for quality, and means for implementing the method Download PDF

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Publication number
WO1986001294A1
WO1986001294A1 PCT/EP1985/000386 EP8500386W WO8601294A1 WO 1986001294 A1 WO1986001294 A1 WO 1986001294A1 EP 8500386 W EP8500386 W EP 8500386W WO 8601294 A1 WO8601294 A1 WO 8601294A1
Authority
WO
WIPO (PCT)
Prior art keywords
plug
concrete
hole
expansion
jack
Prior art date
Application number
PCT/EP1985/000386
Other languages
French (fr)
Inventor
Fiorenzo Meneghetti
Tiziano Meneghetti
Original Assignee
Fiorenzo Meneghetti
Tiziano Meneghetti
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Fiorenzo Meneghetti, Tiziano Meneghetti filed Critical Fiorenzo Meneghetti
Publication of WO1986001294A1 publication Critical patent/WO1986001294A1/en

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
    • G01N33/38—Concrete; ceramics; glass; bricks
    • G01N33/383—Concrete, cement
    • 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
    • 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
    • G01N2203/003—Generation of the force
    • G01N2203/0053—Cutting or drilling tools

Definitions

  • This invention relates to a method of in situ testing concrete for quality, and to means for implementing the method.
  • the method of this invention belongs to the broad class of the "non destructive" testing methods.
  • the tool bit After the tool bit has been anchored securely, it is withdrawn by pulling on it with a jack until the concrete breaks.
  • a consequent primary object is to provide a sequence of operative steps which can be readily implemented without any special difficulties.
  • Another object is to provide a method which can be used at any time after the concrete has been allowed to cure.
  • a further object is to provide a method employing for its operative steps, as far as possible, customary equipment for this field.
  • Still another object is to arrange for the use, wherever feasible, of readily available components on the market.
  • the means for implementing said method comprises a plug arranged to only expand at the deepest portion thereof, and a pulling jack having a swivel device for connection to the plug and an abutment ring whose inside dimensions are selected so as to provide a breaking cone with an angle within the range of about 60° to 70°.
  • Figure 1 is a sectional view of an area where a hole according to this invention has been drilled, which view points out the shape of the hole made in the concrete;
  • Figure 2 illustrates the introduction and the shape of the expansion plug
  • Figure 3 illustrates the expansion of the plug within the hole
  • Figure 4 shows how the abutment ring is positioned and the shape of the breaking cone determined thereby; and Figure 5 is a sectional view through the jack employed for the plug withdrawing step.
  • a cylindrical hole 2 is first drilled which, at its innermost area indicated at 3, is enlarged to provide a conical surface, indicated at 4.
  • This operation is performed by means of a tool which allows the drill bit, that has just formed the cylindrical hole 2 and is suitably designed to only work on the wall of the area 3 of the hole, to be inclined so as to generate an inside taper.
  • a plug 5 is inserted into the hole 2 which comprises a cylindrical sleeve 6 associated, at its most inwardly located portion with respect to the hole, with a plurality of expansion segments 7.
  • the cylindrical sleeve 6 contains a threaded shank 8 the innermost portion whereof is shaped to form an expanding body 9 leaving all around a gap 10 for the insertion of the expanding segments 7.
  • the plug will be anchored securely inside the hole 2.
  • a metal abutment ring 11 is positioned which has a middle hole 12 with its center coinciding with the axis 13 of the threaded shank.
  • the size of the hole 12 is selected so that the angle of the ideal cone to be obtained by joining the cone 9 to the inside circumference 14 of the hole 12 can have an amplitude of 60° to 70o.
  • a jack not shown in Figure 4 which may be of any type so long as it can optically display the force it applies, a pull is exerted on the threaded shank 8 in the direction of the arrow 14 by reaction against the metal abutment ring 11. This pull force is maintained until a concrete cone breaks off which has for its base a circle of the same size as the hole 12 in the abutment ring 11.
  • the height of the cone is instead substantially equal to the length of the plug that had been inserted into the hole.
  • the jack comprises a cylinder 16 accommodating a piston 17 which is driven upward by pressurized oil supplied into the inner chamber 18 of the cylinder through a line 19 from a pump, not shown, to which line 19 a pressure gauge 20 is connected to measure the internal pressure.
  • the piston 17 extends so as to form a rod 21 which, in turn, extends to form a universal joint 22 to which a connector 23 is fitted which is then locked on application of a cross pin 24.
  • Said connector 23 has a threaded hole 25 in which the threaded shank 8 of the plug, previously driven into the concrete, is screwed in.
  • the universal joint and the connector are both contained within a metal bell-like casing 26 which is secured at the top to the cylinder 16 as by screwing, and at the bottom to the abutment ring 11.
  • a comparator 27 serving the function of optically displaying any slipping of the plug, which would be indicative of ineffective grip on the concrete and of an improperly made hole.
  • the universal joint connected between the plug and the jackpiston rod prevents, within limits, the occurrence of an offcenter tensile condition which would alter the readings and make the method unreliable. Such a situation would occur where either the bearing surface of the abutment ring is uneven, or the plug has been inserted into a hole which is not truly perpendicular to the surface of the work.
  • the inventive method described in the foregoing is specially simple in that, with the sole exception of the dynamometric jack, it utilizes standard low cost equipment that is easily operated.
  • the plug may conveniently be of a throw away type, since it is quite simple construction-wise and hence inexpensive to replace. For these reasons, the concrete test may be repeated at several locations without incurring excessive cost.
  • test may be carried out on any structure types whenever their quality must be checked.
  • the plugs while requiring the particular features specified herein before, can be made by using the same equipment and technologies which are used in the manufacture of hardware for concrete.
  • novel aspect of the invention is, therefore, to be seen in the combination of a simple non destructive method that may be applied at any time,with a low cost plug, that may be used once for each test. It may be appreciated from the foregoing description that all of the invention objects have been achieved, and in particular that a specially simple and economically convenient method has been provided which employs low cost materials and components.

Abstract

The method consists of introducing into concrete to be tested (1) a metal expansion plug (5) which is caused to expand inside a previously drilled hole (2) formed with an inside taper (4) that enlarges its cross-section. After tightening, a jack is positioned with an abutment disk (11) having its axis aligned to the plug axis (13) and thereafter a tensile force is applied to the protruding shank of the plug up to the point a breaking of a concrete cone occurs, which cone has a taper angle within the range of 60o to 70o. The value of the tensile load, when read against appropriate tables, enables evaluation of the compressive strength of the concrete being tested.

Description

"METHOD OF IN SITU TESTING CONCRETE FOR QUALITY, AND MEANS FOR IMPLEMENTING THE METHOD" Technical field
This invention relates to a method of in situ testing concrete for quality, and to means for implementing the method. Background Art
Several methods of testing concrete for quality are known which may be classed as "destructive" and "non destructive" methods.
The method of this invention belongs to the broad class of the "non destructive" testing methods.
From the latter, a method is known which provides for a single in situ operation consisting of first drilling a hole, and then enlarging the hole interior with a special cutter until the hole can accommodate a suitable tool bit which will anchor itself within the hole.
After the tool bit has been anchored securely, it is withdrawn by pulling on it with a jack until the concrete breaks.
Such known method, while affording the checking of any part of a structure at any time after its emplacement, shows to be highly expensive in that it requires the availability of special equipment to prepare a hollow seat for a special anchor element. DISCLOSURE OF THE INTENTION It is the technical task of this invention to provide a method which is at one time simple and accurate.
A consequent primary object is to provide a sequence of operative steps which can be readily implemented without any special difficulties.
Another object is to provide a method which can be used at any time after the concrete has been allowed to cure.
A further object is to provide a method employing for its operative steps, as far as possible, customary equipment for this field.
Still another object is to arrange for the use, wherever feasible, of readily available components on the market.
These and other objects, such as will become apparent herein below, are all achieved by a method of in situ testing concrete for quality, characterized in that it comprises the following steps:
(a) drilling concrete to be tested with a perpendicular hole to the concrete surface where the test is to be made;
(b) enlarging the hole interior to provide a frusto-conical area;
(c) introducing an expansion plug into said frusto-conical hole area;
(d) expanding the plug within the hole;
(e) positioning a hydraulic jack equipped with an abutment ring and a swivel means of engagement with said expansion plug, whereafter a pull is applied to the shank of said expansion plug until the concrete breaks and the ultimate tensile strength thereof can be measured. The means for implementing said method comprises a plug arranged to only expand at the deepest portion thereof, and a pulling jack having a swivel device for connection to the plug and an abutment ring whose inside dimensions are selected so as to provide a breaking cone with an angle within the range of about 60° to 70°.
BRIEF DESCRIPTION OF THE DRAWINGS Further features and advantages of the invention will be more clearly undentsood from the following detailed description of a preferred embodiment thereof, given herein by way of illustration and not of limitation with reference to the accompanying drawing sheets, where:
Figure 1 is a sectional view of an area where a hole according to this invention has been drilled, which view points out the shape of the hole made in the concrete;
Figure 2 illustrates the introduction and the shape of the expansion plug; Figure 3 illustrates the expansion of the plug within the hole;
Figure 4 shows how the abutment ring is positioned and the shape of the breaking cone determined thereby; and Figure 5 is a sectional view through the jack employed for the plug withdrawing step.
WAYS OF CARRYING OUT THE INVENTION With reference to the cited drawing figures, in orde to carry out the method of this invention with a concret structure 1 to be tested for quality, a cylindrical hole 2 is first drilled which, at its innermost area indicated at 3, is enlarged to provide a conical surface, indicated at 4.
This operation is performed by means of a tool which allows the drill bit, that has just formed the cylindrical hole 2 and is suitably designed to only work on the wall of the area 3 of the hole, to be inclined so as to generate an inside taper.
Then, a plug 5 is inserted into the hole 2 which comprises a cylindrical sleeve 6 associated, at its most inwardly located portion with respect to the hole, with a plurality of expansion segments 7.
The cylindrical sleeve 6 contains a threaded shank 8 the innermost portion whereof is shaped to form an expanding body 9 leaving all around a gap 10 for the insertion of the expanding segments 7.
Expansion takes place on striking the cylindrical sleeve 6 so that the expansion segments 7 are driven into the gap 10 and made to spread over the cone 9 , as shown in Figure 3»
Thereupon, the plug will be anchored securely inside the hole 2.
By applying then a pull to the threaded shank 8, the segments 7 will be urged further against the conical surface 4 following a possible short initial sliding movement.
On completion of this operation, a metal abutment ring 11 is positioned which has a middle hole 12 with its center coinciding with the axis 13 of the threaded shank. The size of the hole 12 is selected so that the angle of the ideal cone to be obtained by joining the cone 9 to the inside circumference 14 of the hole 12 can have an amplitude of 60° to 70º. At this point, using a jack not shown in Figure 4 which may be of any type so long as it can optically display the force it applies, a pull is exerted on the threaded shank 8 in the direction of the arrow 14 by reaction against the metal abutment ring 11. This pull force is maintained until a concrete cone breaks off which has for its base a circle of the same size as the hole 12 in the abutment ring 11. The height of the cone is instead substantially equal to the length of the plug that had been inserted into the hole.
The value which has been ascertained of the breaking stress on the concrete, when compared to appropriate tables, enables the characteristics of the concrete to be evaluated. A suitable jack for implementing the method in combination with the plug described above, is shown in Figure 5.
As may be seen, the jack comprises a cylinder 16 accommodating a piston 17 which is driven upward by pressurized oil supplied into the inner chamber 18 of the cylinder through a line 19 from a pump, not shown, to which line 19 a pressure gauge 20 is connected to measure the internal pressure.
The piston 17 extends so as to form a rod 21 which, in turn, extends to form a universal joint 22 to which a connector 23 is fitted which is then locked on application of a cross pin 24.
Said connector 23 has a threaded hole 25 in which the threaded shank 8 of the plug, previously driven into the concrete, is screwed in. The universal joint and the connector are both contained within a metal bell-like casing 26 which is secured at the top to the cylinder 16 as by screwing, and at the bottom to the abutment ring 11. At the upper portion between the shank 21 and cylinder 16, there is mounted a comparator 27 serving the function of optically displaying any slipping of the plug, which would be indicative of ineffective grip on the concrete and of an improperly made hole. The universal joint connected between the plug and the jackpiston rod prevents, within limits, the occurrence of an offcenter tensile condition which would alter the readings and make the method unreliable. Such a situation would occur where either the bearing surface of the abutment ring is uneven, or the plug has been inserted into a hole which is not truly perpendicular to the surface of the work.
The inventive method described in the foregoing is specially simple in that, with the sole exception of the dynamometric jack, it utilizes standard low cost equipment that is easily operated.
The plug may conveniently be of a throw away type, since it is quite simple construction-wise and hence inexpensive to replace. For these reasons, the concrete test may be repeated at several locations without incurring excessive cost.
Evidently, the test may be carried out on any structure types whenever their quality must be checked.
This is specially advantageous both with new structures and with structures that for a reason whatever have undergone exceptional stresses, such as earthquake vibrations, the effects of which may create a potentially dangerous situation and command, therefore, an accurate checkup.
The plugs, while requiring the particular features specified herein before, can be made by using the same equipment and technologies which are used in the manufacture of hardware for concrete.
The novel aspect of the invention is, therefore, to be seen in the combination of a simple non destructive method that may be applied at any time,with a low cost plug, that may be used once for each test. It may be appreciated from the foregoing description that all of the invention objects have been achieved, and in particular that a specially simple and economically convenient method has been provided which employs low cost materials and components.
From experimental tests, it appears that the angle which yields the best direct correlation of compressive strength to extraction force is in the 60° to 70° range. Based on this angle range, charts and graphs have been prepared which make the interpretation of the test results an easy task.
Of course, this inventive concept may be implemented by means which are different from the ones described, so long the method remains the same.

Claims

CLAIMS 1. A method of in situ testing concrete for quality, characterized in that it comprises the following steps: a) drilling concrete to be tested with a perpendicular hole to the concrete surface; b) enlarging the innermost portion of the hole to provide a frusto-conical cavity; c) introducing an expansion plug into said frusto-conical hole area; d) expanding the plug within the hole; e) positioning a jack equipped with an abutment ring and a swivel means of engagement with said expansion plug, whereafter a pull is applied to the shank of said expansion plug until the concrete breaks and the ultimate tensile strength thereof can be measured. 2. A method according to claim 1, characterized in that said innermost portion of the hole is enlarged with a suitable drill bit guided by a tool which allows for a wobbling movement thereof to only enlarge the hole at its innermost portion. 3. A method according to claim 1, characterized in that the expansion of the plug is conveniently brought about by striking its body to drive expansion segments into the gap between the plug and hole wall. 4. A means for implementing the method according to claim 1 which comprises a plug arranged to only expand at the deepest portion thereof, and a pulling jack having a swivel device for connection to the plug and an abutment ring whose inside dimensions are selected to provide a breaking cone with an angle within the range of about 60° to 70°. 5. A means according to claim 4, characterized in that said expansion plug comprises substantially a cylindrical sleeve associated with a plurality of expansion segments, there being inserted into said sleeve a threaded shank which has, on the side of said expansion segments, a conical enlargement. 6. A means according to claim 4, characterized in that said abutment ring has a central hole of a size such as to form a breaking cone with an angle of 60° to 70°, and with a height being equal to the inserted plug length. 7. A means according to claim 4, characterized in that said jack has a mechanical swivel joint to connect the movable rod thereof under oil pressure to the plug shank, said swivel joint being adapted to make the plug and the jack piston rod axially independent during the pull operations. 8. A means according to claim 4, characterized in that said swivel joint is a universal joint. 9. A means according to one or more of the claims 4 to 8, characterized in that it comprises experimental charts adapted to allow the concrete characteristics to be determined according to the extraction force which breaks off a concrete cone. 10. A method of in situ testing concrete for quality and means for implementing said method, characterized in that they comprise one or more of the features herein illustrated and described.
PCT/EP1985/000386 1984-08-03 1985-07-31 Method of iota situ) testing concrete for quality, and means for implementing the method WO1986001294A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT41616A/84 1984-08-03
IT41616/84A IT1181003B (en) 1984-08-03 1984-08-03 PROCEDURE FOR THE ON-SITE ANALYSIS OF THE QUALITY OF CONCRETE AND MEANS TO IMPLEMENT THE PROCEDURE

Publications (1)

Publication Number Publication Date
WO1986001294A1 true WO1986001294A1 (en) 1986-02-27

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PCT/EP1985/000386 WO1986001294A1 (en) 1984-08-03 1985-07-31 Method of iota situ) testing concrete for quality, and means for implementing the method

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EP (1) EP0188586A1 (en)
IT (1) IT1181003B (en)
WO (1) WO1986001294A1 (en)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2301191A (en) * 1995-05-26 1996-11-27 Electricity Corp The Tool for measuring decay in wood
WO2007145753A3 (en) * 2006-06-05 2008-02-07 Illinois Tool Works Anchor bolt and annularly grooved expansion sleeve assembly exhibiting high pull-out resistance, particularly under cracked concrete test conditions
US7744320B2 (en) 2006-06-05 2010-06-29 Illinois Tool Works Inc. Anchor bolt and annularly grooved expansion sleeve assembly exhibiting high pull-out resistance, particularly under cracked concrete test conditions
JP2015025352A (en) * 2013-06-21 2015-02-05 株式会社大林組 Post-installed anchor construction method
CN105716976A (en) * 2016-03-04 2016-06-29 衢州康平建设工程检测有限公司 Plastering mortar compressive strength in-situ sphere indentation detector and detection method thereof
JP2017215292A (en) * 2016-06-02 2017-12-07 サンコーテクノ株式会社 Method and device for evaluating bond strength of repair material layer
CN109520838A (en) * 2018-12-25 2019-03-26 西南交通大学 A kind of shield tunnel screwed joint tensile property experimental rig
JP7463031B2 (en) 2020-03-18 2024-04-08 株式会社電業社機械製作所 Pull-out test machine and pull-out test method

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3283566A (en) * 1964-01-29 1966-11-08 Dale H Fietz Material hardness tester
FR1574024A (en) * 1968-03-29 1969-07-11
US3640126A (en) * 1968-08-07 1972-02-08 Nat Res Dev Testing of concrete
FR2346591A1 (en) * 1976-03-30 1977-10-28 Schafers Heinrich ANCHOR AND ANCHOR METHOD FOR THIS EFFECT
US4103540A (en) * 1977-09-23 1978-08-01 Mclaughlin Robert R Testing device for in-site cementitious material
EP0067941A2 (en) * 1981-06-24 1982-12-29 Fischerwerke Arthur Fischer GmbH & Co. KG Expansive bolt for anchoring in bore-holes with conical internal enlargement

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3283566A (en) * 1964-01-29 1966-11-08 Dale H Fietz Material hardness tester
FR1574024A (en) * 1968-03-29 1969-07-11
US3640126A (en) * 1968-08-07 1972-02-08 Nat Res Dev Testing of concrete
FR2346591A1 (en) * 1976-03-30 1977-10-28 Schafers Heinrich ANCHOR AND ANCHOR METHOD FOR THIS EFFECT
US4103540A (en) * 1977-09-23 1978-08-01 Mclaughlin Robert R Testing device for in-site cementitious material
EP0067941A2 (en) * 1981-06-24 1982-12-29 Fischerwerke Arthur Fischer GmbH & Co. KG Expansive bolt for anchoring in bore-holes with conical internal enlargement

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2301191A (en) * 1995-05-26 1996-11-27 Electricity Corp The Tool for measuring decay in wood
US5792960A (en) * 1995-05-26 1998-08-11 The Electricity Corporation Tool for measuring decay in wood
GB2301191B (en) * 1995-05-26 1999-06-02 Electricity Corp The Tool for measuring decay in wood
WO2007145753A3 (en) * 2006-06-05 2008-02-07 Illinois Tool Works Anchor bolt and annularly grooved expansion sleeve assembly exhibiting high pull-out resistance, particularly under cracked concrete test conditions
US7744320B2 (en) 2006-06-05 2010-06-29 Illinois Tool Works Inc. Anchor bolt and annularly grooved expansion sleeve assembly exhibiting high pull-out resistance, particularly under cracked concrete test conditions
US7811037B2 (en) 2006-06-05 2010-10-12 Illinois Tool Works Inc. Anchor bolt and annularly grooved expansion sleeve assembly exhibiting high pull-out resistance, particularly under cracked concrete test conditions
US8302276B2 (en) 2006-06-05 2012-11-06 Illinois Tool Works Inc. Anchor bolt and annularly grooved expansion sleeve assembly exhibiting high pull-out resistance, particularly under cracked concrete test conditions
US8491244B2 (en) 2006-06-05 2013-07-23 Illinois Tool Works Inc. Anchor bolt and annularly grooved expansion sleeve assembly exhibiting high pull-out resistance, particularly under cracked concrete test conditions
JP2015025352A (en) * 2013-06-21 2015-02-05 株式会社大林組 Post-installed anchor construction method
CN105716976A (en) * 2016-03-04 2016-06-29 衢州康平建设工程检测有限公司 Plastering mortar compressive strength in-situ sphere indentation detector and detection method thereof
JP2017215292A (en) * 2016-06-02 2017-12-07 サンコーテクノ株式会社 Method and device for evaluating bond strength of repair material layer
CN109520838A (en) * 2018-12-25 2019-03-26 西南交通大学 A kind of shield tunnel screwed joint tensile property experimental rig
CN109520838B (en) * 2018-12-25 2023-12-15 西南交通大学 Tensile property test device for shield tunnel bolt joint
JP7463031B2 (en) 2020-03-18 2024-04-08 株式会社電業社機械製作所 Pull-out test machine and pull-out test method

Also Published As

Publication number Publication date
IT8441616A1 (en) 1986-02-03
EP0188586A1 (en) 1986-07-30
IT1181003B (en) 1987-09-23
IT8441616A0 (en) 1984-08-03

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