Antonio brencich, giancarlo cassini, davide pera, giuseppe riotto. Pdf application of rebound hammer method for estimating. Digital and manual schmidt concrete test hammers for quick and easy determination of concrete compressive strength. The schmidt hammer provides a quick and inexpensive measure of surface hardness that is widely used for estimating the mechanical properties of rock material. Bureau of indian standard did not published any standard for this test upto 1991. Standard test method for rebound number of hardened concrete1 this standard is issued under the. The main components include the outer body, the plunger, the hammer. Rebound hammer test is conducted around all the points of observation on all accessible faces of the structural element. The original schmidt hammer is known for its durability and accuracy. Calibration and reliability of the rebound schmidt. Basu and aydin 2004 proposed an analytical formulation for normalization of the schmidt hammer rebound values and experimentally verified its applicability to a wide range of rock materials. Rebound hammer test procedure for concrete hardness.
The rebound hammer, developed by ernst schmidt, provides an inexpensive and quick method for nondestructive testing and evaluation of the hardness of concrete. Pdf rebound hammer test method statement rusi sumdaram. The rebound hammer is a simple and inexpensive apparatus that is used to determine the strength of materials which was first invented in the 1950s by ernst o. Schmidt hammer test or rebound hammer test of concrete. Rebound hammer test rebound hammer test is done to find out the compressive strength of concrete by using rebound hammer as per is. Then the compressive strength was ascer tained on a pressure. The rebound hammer has been around since the late 1940s and today is a commonly used method for estimating the compressive strength of inplace concrete. The experimental studies using ultrasonic pulse velocity and schmidt rebound hammer as nondestructive tests ndt were presented in this paper to establish a correlation between the compressive strengths of compression tests and ndt values. The original schmidt is fully compliant with all major. For taking a measurement, the rebound hammer should be held at right angles to them surface of the concrete member. Rubene and vilnitis performed a series of laboratory tests. It was invented by ernst schmidt, a swiss engineer.
Also, beware of the piston and hammer be com ing dirty from oil or dust from the contact surface, as this could create errors in the rebound impact. Digital rebound hammers testing compressive strength and. Description the schmidt os120 pendulum hammers are designed to test on softer material such as light weight concrete, gypsum boards, fresh concrete and the mortar of joints in brickwork. The hammer is intended for testing the quality of concrete in finished structures such as buildings and bridges. Schmidt rebound hammer portfolio from proceq duration. Schmidt hammers, or concrete test hammers, are used to determine inplace strength of concrete. Digital rebound hammers for the quick and easy determination of the strength of concrete, and hardness of construction materials. Original schmidt rebound hammer manual proceq make portable and flexible, simple and convenient to use, impact energy. In the procedure of rebound hammer test, the plunger of rebound hammer is pressed on the surface of concrete, so that a spring controlled mass with a constant energy is made to hit the concrete. This normalization method can be used for any type of schmidt hammer fired in any direction, and is proven to be more accurate than empirical methods.
No other manufacturer offers such a wide range of different types. Pdf calibration and reliability of the rebound schmidt hammer test. Supplied complete with carrying case and carborundum stone, the hammer is suitable for testing concrete with compressive strengths of. You will hear a click, and the piston will extend into the test position. Standard test method for rebound number of hardened concrete, astm international, west.
The rebound value is dependent on the impact direction. The rebound hammer is also called as schmidt hammer that consist of a spring controlled mass that slides on a plunger within a tubular housing. The type n schmidt hammer is pressed against the concrete structure and the rebound values are displayed on a mechanical sliding scale. Rebound hammer standards the silverschmidt is fully compliant with astm c805, en 125042 and en 791. In each test, at least 10 test hammer impacts were performed on one. The silverschmidt measures the velocity of impact and of rebound, immediately before and after. Doc rebound hammer test result prince patwa academia. Supplied complete with carrying case and carborundum stone, the hammer is suitable for testing concrete with compressive strengths of 10 to 70 nmm2. The unique design and high quality construction of the silverschmidt address all of these issues and makes rebound hammer testing quicker and more accurate than ever before. The functionality of the rebound hammer shall have been verified in accordance with 6. Assessing the rebound hammer test for rammed earth.
Lump tests on saturated small lumps of asperities give a better ucs or jcs o. May 27, 2018 rebound hammer test schmidt s hammer a non destructive test on concrete surface hardness test duration. Around each point of observation, six readings of rebound indices are taken and average of these. A schmidt hammer, also known as a swiss hammer or a rebound hammer or concrete hammer test, is a device to measure the elastic properties or strength of concrete or rock, mainly surface hardness and penetration resistance. With this development the hardness measurement became. Analysis of impact hammer rebound to estimate rock drillability. The rebound value is affected by internal friction. Estimating the strength of concrete using surface rebound. Rebound hammer standards the silverschmidt is fully compliant with en 125042 and en 791. Pdf the schmidt hammer in rock material characterization.
The concrete rebound hammer is an instrument which is easy to use, for quick and approximate measurement of the resistance to pressure of manufactured concrete products. Abstract one of the most widely spread techniques to estimate the compressive strength of concrete is the rebound hammer test, also known as schmidt. Mishra associate professor may, 2016 supervisors certificate this is to certify that the work presented in this dissertation entitled application of schmidt rebound. This concrete test hammer, entirely produced by matest, has aluminium frame and thanks to its very accurate manufacture processing and selected components ensures high precision test results in. Rebound hammer sgm lab solutions was established with an aim to serve a wide variety of laboratory and ndt equipments. Moreover, we will discuss how to estimate concrete strength using rebound hammer. C805 c805m18 standard test method for rebound number of hardened concrete rebound number insulating boards springdriven steel hammers. Standard test method for rebound number of hardened. Compressive strength of concrete cube test pdf, procedure, results. However, it typically has the largest coefficient of variation. It was devised in 1948 by ernst schmidt, and is therefore. Developed in 1948 by a swiss engineer named ernst schmidt, the device measures the hardness of concrete surfaces.
Quartzcoated joints in weak rock can give a high schmidt hammer rebound number, which is a surface property bhasin, 2004. Contents principle of rebound hammer test working of rebound hammer test limitations of rebound hammer test disadvantages of rebound hammer this is one of the oldest nondestructive tests and it is still widely used. University of genova, department of civil, chemical and environmental engineering, via montallegro 1, 16145 corresponding author. Swiss engineer ernst schmidt is the name of the scientist who first introduced rebound hammer test, and it is also called as schmidt hammer test or swiss hammer test. Concrete rebound hammer test was first covered by is 311 part 2 1992. The following standards have been applied in silver schmidt for the procedure to determine the rebound number. Rebound hammer test, schmidt hammer test, nondestructive. Nowadays, the schmidt rebound hammer is still the surface hardness testing device of the most widespread use for concrete rather than devices of plastic indentation hardness testing. Swiss engineer named ernst schmidt, the device measures the hardness of concrete surfaces using the rebound principle. Humboldts concrete rebound hammer provides a reliable, yet economical, alternative to the original schmidt hammer.
Correlation between schmidt hammer and destructive. All about structural analysis and design 28,5 views. If the situation demands,the rebound hammer can be. Rebound hammer test is the most appropriate and useful testing methods for comparing the relatively weaker and stronger areas of concrete. The schmidt hammer in rock material characterization. Rebound hammer can be used very easily and the measure of hardness i. The silverschmidt is an integrated electronic schmidt hammer, featuring greater ease of use and. The chinese standard been applied in silverschmidt for the procedure to determine the rebound number. Procedure for rebound hammer test procedure for rebound hammer test on concrete structure starts with calibration of the rebound hammer.
The concrete test hammer invented by ernst schmidt and introduced by proceq at the beginning of the 1950s remains to this day the most. The device used in the test known as schmidt hammer or rebound hammer, uses a spring and measures the hardness of concrete surface using the rebound principle 2. Nondestructive testing of concrete by rebound hammer. The rebound hammer test is codified in astm c805 3 and csn en 125042 4. Concrete rebound hammer tester resiliometer schmidt hammer zc3a with english label advantage and feature the concrete rebound hammer is in accordance with technical regulation of jgjt232001, used for testing of concrete compressive strength within the scope of 1060mpa, with the system s tandard energy of 2. Pdf calibration and reliability of the rebound schmidt. Jul 09, 2019 the rebound hammer, developed by ernst schmidt, provides an inexpensive and quick method for nondestructive testing and evaluation of the hardness of concrete. Schmidt rebound hammer test and concrete destructive compression test. Locations having very low rebound numbers indicate weak surface concrete and may be affected by corrosion. Then the compressive strength was ascertained on a pressure testing machine. For this, the rebound hammer is tested against the test anvil made of steel having brinell hardness number of about 5000 nmm2. Astm c805 c805m 18 standard test method for rebound. Proper use of the rebound hammer updated to reflect the. These values can then be correlated to compressive strength by using the conversion table chart affixed to the hammer.
Always hold the rebound hammer with both hands perpendicular to the surface. Methodology for schmidt data collection and conversion of schmidt rebound to shear modulus introduction this section explains the conversion of schmidt hammer rebound number to shear modulus, and subsequently the determination of the rigidity contrast ratio in evidence. The rebound of an elastic mass depends on the hardness of the surface against which its mass strikes. Betonprufhammer bedienungsanleitung sclerometre a beton nnr. Rebound hammer is also known as schmidt s hammer or swiss hammer as it is invented by ernst schmidt, a swiss engineer. Rebound hammer test is a nondestructive testing method of concrete which. The manual concrete test hammer, aka rebound hammer, schmidt hammer, swiss hammer, sclerometer, is the most widely used non destructive instrument for compressive strength determination. Concrete surfaces are thoroughly cleaned before taking any measurement. Typically, a rebound hammer will result in a rebound number of 80 2 when tested on the anvil described in section 4. It is designed for testing concrete 4 100mm or more in thickness with a maximum particle size less than or equal to 1. The test can thus be conducted horizontally on vertical surfaces or vertically upwards or downwards on horizontal surfaces. The orientation of the hammer will in turn affect the rebound reading. The classic original schmidt hammer that became the basis of every major rebound hammer testing standard worldwide. Suitable for finished concrete structures and buildings having strength resistances from 10 to 70 nsq.
A number in parentheses indicates the year of last reapproval. The concrete test hammer invented by ernst schmidt and introduced by proceq at the beginning of the 1950s remains to this day the most widely used nondestructive test instrument for a. The original schmidt is fully compliant with all major standards. The rebound values r of the sample cubes were measured using the concrete test hammer. A schematic cutaway view of the rebound hammer is shown in. In switzerland ernst schmidt developed a spring impact hammer of which handling was found to be superior to the ball penetration tester devices schmidt, 1950. Cgoldenwall concrete rebound hammer tester resiliometer. Review of the rebound hammer method estimating concrete. Original schmidt rebound hammer manual proceq make. All of the concrete rebound hammers we carry below accurately measure compressive strength of concrete, which directly determines the loadbearing capacity and durability of concrete structures. The rebound hammer is also called as schmidt hammer that consist of a spring. The hardness testing method of shore 1911 was adopted in the device developed by schmidt, and the measure of surface hardness is the rebound index rather than ball penetration. Isrm suggested method isrm suggested method for determination of the schmidt hammer rebound hardness. Rebound hammer test schmidt hammer testing on concrete.
The rational use of the various available methods, as well as a possible combination of more than one method, can be particularly interesting from the viewpoint of the validity of results. The main components include the outer body, the plunger, the hammer mass, and the main spring. Calibration and reliability of the rebound schmidt hammer test. Description the schmidt os120 pendulum hammers are designed to test on softer material such as light weight concrete, gypsum boards, fresh concrete and. This device is universally used because of a hardened steel hammerimpacted on the concrete by a spring. Aug 05, 2018 concrete rebound hammer test was first covered by is 311 part 2 1992. Rebound hammer test is done to find out the compressive strength of concrete by using rebound hammer as per is. Limited tightness of sealing causes premature loss of accuracy. The test anvil needs to be supported on a rigid base to obtain reliable rebound numbers.
Estimate concrete strength using rebound hammer fprimec. The underlying principle of the rebound hammer test is. Standard test method for rebound number of hardened concrete. In order to calibrate the schmidt hammer with the variousaged. The silverschmidt measures the velocity of impact and of rebound. Brencich and others published calibration and reliability of the rebound schmidt hammer test find, read and cite. Each hammer is designed for specific test applications. Rebound hammer test on concrete principle, procedure. Surface hardness measured during the test give an idea about the soundness and quality of cover concrete. Application of rebound hammer method for estimating. Pdf concrete is the most commonly used construction materials in structures. This paper theoretically analyzes the hammer rebound in the schmidt impact hammer and in a drill with a downhole hammer. The schmidt hammer gives wrong results on rough joints. Rebound hammer is also known as schmidts hammer or swiss hammer as it is invented by ernst schmidt, a swiss engineer.
Nondestructive testing of concrete methods of test. The rebound hammer or schmidt hammer test is a nondestructive test widely used for concrete, due to its simplicity, speed, and low cost 30. Mining engineering national institute of technology rourkela dr. A simple equipment known as rebound hammer or schmidt hammer is used for this purpose. Each rebound hammer is built for a different purpose in or.
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