Rebound hammer test, schmidt hammer test, nondestructive. In order to calibrate the schmidt hammer with the variousaged. The rebound values r of the sample cubes were measured using the concrete test hammer. Bureau of indian standard did not published any standard for this test upto 1991. Concrete surfaces are thoroughly cleaned before taking any measurement. May 27, 2018 rebound hammer test schmidt s hammer a non destructive test on concrete surface hardness test duration. The rebound of an elastic mass depends on the hardness of the surface against which its mass strikes. Schmidt hammer test or rebound hammer test of concrete. The concrete test hammer invented by ernst schmidt and introduced by proceq at the beginning of the 1950s remains to this day the most. Standard test method for rebound number of hardened concrete1 this standard is issued under the. Pdf rebound hammer test method statement rusi sumdaram. Surface hardness measured during the test give an idea about the soundness and quality of cover concrete. The main components include the outer body, the plunger, the hammer mass, and the main spring.
The rebound value is affected by internal friction. Pdf concrete is the most commonly used construction materials in structures. 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. Schmidt rebound hammer portfolio from proceq duration. Schmidt rebound hammer test and concrete destructive compression test.
The main components include the outer body, the plunger, the hammer. 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. The schmidt hammer provides a quick and inexpensive measure of surface hardness that is widely used for estimating the mechanical properties of rock material. Rebound hammer test rebound hammer test is done to find out the compressive strength of concrete by using rebound hammer as per is. These values can then be correlated to compressive strength by using the conversion table chart affixed to the hammer. Pdf calibration and reliability of the rebound schmidt hammer test. 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. You will hear a click, and the piston will extend into the test position. 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. 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. 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. Aug 05, 2018 concrete rebound hammer test was first covered by is 311 part 2 1992.
Digital rebound hammers for the quick and easy determination of the strength of concrete, and hardness of construction materials. Doc rebound hammer test result prince patwa academia. Betonprufhammer bedienungsanleitung sclerometre a beton nnr. Standard test method for rebound number of hardened concrete, astm international, west. The chinese standard been applied in silverschmidt for the procedure to determine the rebound number. Digital rebound hammers testing compressive strength and. If the situation demands,the rebound hammer can be. Rebound hammer standards the silverschmidt is fully compliant with astm c805, en 125042 and en 791.
The silverschmidt is an integrated electronic schmidt hammer, featuring greater ease of use and. 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. 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. In each test, at least 10 test hammer impacts were performed on one. 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. 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. All about structural analysis and design 28,5 views. 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. The rebound value is dependent on the impact direction. Compressive strength of concrete cube test pdf, procedure, results. Nondestructive testing of concrete by rebound hammer. 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. C805 c805m18 standard test method for rebound number of hardened concrete rebound number insulating boards springdriven steel hammers. The hammer is intended for testing the quality of concrete in finished structures such as buildings and bridges. With this development the hardness measurement became.
Rebound hammer test is done to find out the compressive strength of concrete by using rebound hammer as per is. 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. Rubene and vilnitis performed a series of laboratory tests. Rebound hammer test procedure for concrete hardness. Suitable for finished concrete structures and buildings having strength resistances from 10 to 70 nsq. Pdf application of rebound hammer method for estimating. University of genova, department of civil, chemical and environmental engineering, via montallegro 1, 16145 corresponding author. The rebound hammer test is codified in astm c805 3 and csn en 125042 4. No other manufacturer offers such a wide range of different types. 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. Application of rebound hammer method for estimating.
The schmidt rebound hammer is principally a surface hardness tester with an apparent theoretical relationship between the strength of concrete and the rebound number of the hammer. 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. Rebound hammer test is the most appropriate and useful testing methods for comparing the relatively weaker and stronger areas of concrete. Concrete rebound hammer test was first covered by is 311 part 2 1992. Rebound hammer test schmidt hammer testing on concrete. Digital and manual schmidt concrete test hammers for quick and easy determination of concrete compressive strength. 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. Assessing the rebound hammer test for rammed earth. 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. The silverschmidt measures the velocity of impact and of rebound, immediately before and after.
Estimating the strength of concrete using surface rebound. The silverschmidt measures the velocity of impact and of rebound. Procedure for rebound hammer test procedure for rebound hammer test on concrete structure starts with calibration of the rebound hammer. Lump tests on saturated small lumps of asperities give a better ucs or jcs o. Pdf the schmidt hammer in rock material characterization.
Supplied complete with carrying case and carborundum stone, the hammer is suitable for testing concrete with compressive strengths of 10 to 70 nmm2. 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. Moreover, we will discuss how to estimate concrete strength using rebound hammer. Quartzcoated joints in weak rock can give a high schmidt hammer rebound number, which is a surface property bhasin, 2004. The functionality of the rebound hammer shall have been verified in accordance with 6. The schmidt hammer gives wrong results on rough joints.
The surface of hardened concrete is struck with the hammer, and concrete compressive strength is estimated via the surface hardness rebound value. Around each point of observation, six readings of rebound indices are taken and average of these. Analysis of impact hammer rebound to estimate rock drillability. Correlation between schmidt hammer and destructive. 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. Supplied complete with carrying case and carborundum stone, the hammer is suitable for testing concrete with compressive strengths of. A number in parentheses indicates the year of last reapproval. The rebound hammer is also called as schmidt hammer that consist of a spring. Calibration and reliability of the rebound schmidt hammer test. Acceptability of rebound hammer test is evaluated by different research works and studies. The schmidt hammer in rock material characterization.
Review of the rebound hammer method estimating concrete. 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. The following standards have been applied in silver schmidt for the procedure to determine the rebound number. Each rebound hammer is built for a different purpose in or. Proper use of the rebound hammer updated to reflect the. Isrm suggested method isrm suggested method for determination of the schmidt hammer rebound hardness. Estimate concrete strength using rebound hammer fprimec. The test anvil needs to be supported on a rigid base to obtain reliable rebound numbers. Antonio brencich, giancarlo cassini, davide pera, giuseppe riotto. Locations having very low rebound numbers indicate weak surface concrete and may be affected by corrosion. Rebound hammer is also known as schmidt s hammer or swiss hammer as it is invented by ernst schmidt, a swiss engineer. 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.
Standard test method for rebound number of hardened. It is designed for testing concrete 4 100mm or more in thickness with a maximum particle size less than or equal to 1. Rebound hammer can be used very easily and the measure of hardness i. Always hold the rebound hammer with both hands perpendicular to the surface. For taking a measurement, the rebound hammer should be held at right angles to them surface of the concrete member. The type n schmidt hammer is pressed against the concrete structure and the rebound values are displayed on a mechanical sliding scale. Nondestructive testing of concrete methods of test. The original schmidt hammer is known for its durability and accuracy. The rebound hammer, developed by ernst schmidt, provides an inexpensive and quick method for nondestructive testing and evaluation of the hardness of concrete. The original schmidt is fully compliant with all major. A schematic cutaway view of the rebound hammer is shown in.
Limited tightness of sealing causes premature loss of accuracy. The classic original schmidt hammer that became the basis of every major rebound hammer testing standard worldwide. Pdf calibration and reliability of the rebound schmidt. The rebound hammer or schmidt hammer test is a nondestructive test widely used for concrete, due to its simplicity, speed, and low cost 30. Calibration and reliability of the rebound schmidt. Mishra associate professor may, 2016 supervisors certificate this is to certify that the work presented in this dissertation entitled application of schmidt rebound. Each hammer is designed for specific test applications.
Original schmidt rebound hammer manual proceq make portable and flexible, simple and convenient to use, impact energy. Then the compressive strength was ascertained on a pressure testing machine. Original schmidt rebound hammer manual proceq make. 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. Astm c805 c805m 18 standard test method for rebound. Abstract one of the most widely spread techniques to estimate the compressive strength of concrete is the rebound hammer test, also known as schmidt. Description the schmidt os120 pendulum hammers are designed to test on softer material such as light weight concrete, gypsum boards, fresh concrete and.
Rebound hammer test on concrete principle, procedure. Humboldts concrete rebound hammer provides a reliable, yet economical, alternative to the original schmidt hammer. Typically, a rebound hammer will result in a rebound number of 80 2 when tested on the anvil described in section 4. The underlying principle of the rebound hammer test is. Developed in 1948 by a swiss engineer named ernst schmidt, the device measures the hardness of concrete surfaces.
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 orientation of the hammer will in turn affect the rebound reading. Swiss engineer named ernst schmidt, the device measures the hardness of concrete surfaces using the rebound principle. Mining engineering national institute of technology rourkela dr. Rebound hammer sgm lab solutions was established with an aim to serve a wide variety of laboratory and ndt equipments. 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. For this, the rebound hammer is tested against the test anvil made of steel having brinell hardness number of about 5000 nmm2. Schmidt hammers, or concrete test hammers, are used to determine inplace strength of concrete. 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. Rebound hammer standards the silverschmidt is fully compliant with en 125042 and en 791. This paper theoretically analyzes the hammer rebound in the schmidt impact hammer and in a drill with a downhole hammer. The original schmidt is fully compliant with all major standards. It was devised in 1948 by ernst schmidt, and is therefore.
A simple equipment known as rebound hammer or schmidt hammer is used for this purpose. Rebound hammer test is a nondestructive testing method of concrete which. 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. Brencich and others published calibration and reliability of the rebound schmidt hammer test find, read and cite. Rebound hammer is also known as schmidts hammer or swiss hammer as it is invented by ernst schmidt, a swiss engineer. However, it typically has the largest coefficient of variation. It was invented by ernst schmidt, a swiss engineer. This device is universally used because of a hardened steel hammerimpacted on the concrete by a spring.
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