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• the tool bit After the tool bit has been anchored securely, it is withdrawn by pulling on it with a jack until the concrete breaks.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.

Applications Claiming Priority (2)

Publications (1)

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Country Status (3)

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Family Cites Families (6)

• 1984
  • 1984-08-03 IT IT41616/84A patent/IT1181003B/it active
• 1985
  • 1985-07-31 EP EP85903837A patent/EP0188586A1/en not_active Withdrawn
  • 1985-07-31 WO PCT/EP1985/000386 patent/WO1986001294A1/en unknown

Non-Patent Citations (1)

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