The most satisfactory way of establishing a correlation between compressive strength of concrete and its rebound number is to measure both the properties simultaneously on concrete cubes. Review of key issues and ideas for more reliable conclusions article pdf available in materials and structures 479 september 2014 with 2,956. The rebound hammer, developed by ernst schmidt, provides an inexpensive and quick method for nondestructive testing and evaluation of the. 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. Always hold the concrete rebound hammer in both hands while in use. Principles of the rebound hammer ernst schmidt, a swiss engineer, developed the modern rebound hammer in 1948.
Rebound hammer test, which is also called as the schmidt hammer test. 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. Testing the strength of concrete without destructing or breaking it after hardening is a complex task. The schmidt hammer test involves hitting the insitu concrete with a springdriven pin at a defined energy, and then the rebound is measured. Concretemethodsoftest part 2 rebound hammer 1 scope this standard covers the object, principle, apparatus and procedure of rebound hammer test method. The test can thus be conducted horizontally on vertical surfaces or vertically upwards or downwards on horizontal surfaces. Estimate concrete strength using rebound hammer fprimec. Rebound hammer test is a nondestructive testing method of concrete which provide a convenient and rapid indication of the rebound hammer test is a nondestructive testing method of concrete. The rebound hammer is also one of the easiest pieces of equipment to misuse. Acceptability of rebound hammer test is evaluated by different research works and studies. Standard test method for rebound number of hardened. Nondestructive testing of concrete by rebound hammer.
This is a form of ndt and a fast and simple way to test concrete. Pdf rebound hammer test method statement rusi sumdaram. As we already discussed the compressive strength of concrete by concrete cube test which is a destructive test worked out in the lab. Rebound hammer determination of compressive strength of hardened concrete 1. Is schmidt hammer test a standard test for testing. Schmidt rebound test hammers invented by proceq and is the most widely used ndt instrument for concrete strength testing, asphalt, mortar, rock and paper. Developed in 1948 by a swiss engineer named ernst schmidt, the device measures the hardness of concrete surfaces. Concrete inspection rebound hammer elcometer 181 analogue concrete test hammer standards. Standard test method for rebound number of hardened concrete1. However, the test is imprecise and cannot accurately predict the strength of concrete. Rebound hammer tests and postinstalled pullout tests are commonly used for evaluating the compressive strength of ordinary concrete, and the strength of concrete is estimated by strength curves. When the plunger of rebound hammer is pressed against the surface of the concrete, the spring controlled mass rebounds and the extent. In 1948, a swiss engineer, ernst schmidt developed a test hammer for measuring the hardness of concrete by the rebound principle. For taking a measurement, the rebound hammer should be held at right angles to them surface of the concrete member.
Also, when in use, keep the hammer perpendicular to the surface you are testing with the scale pointing up, making it easier to read. Operating principle of the rebound hammer physical principle the test hammer rebound hammer is intended to measure the surface hardness of concrete and there is an empirical relationship between the compressive strength of concrete and the rebound index which is a code. 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 silverschmidt stpc is the first integrated concrete test hammer featuring true rebound value and unmatched repeatability. It has been used worldwide as an index test for a testing equipment to estimate strength of concrete due to its rapidity and easiness in execution, simplicity, portability, low cost and nondestructiveness. Schmidt hammer test is the most commonly used one in practice.
It is one of the most useful non destructive techniques in evaluation of concrete structures. Astm c805, standard test method for rebound number of hardened concrete, summarizes the procedure as a steel hammer impacts, with a predetermined. The rebound hammer test is currently the most common method of testing the hardness of concrete and was. This test is also known as the schmidt hammer or impact hammer, and is a nondestructive method of testing concrete. The test has widely been used, since its introduction in 1948. The hammer is intended for testing the quality of concrete in finished structures such as buildings and bridges. At the same time, a spring controlled mass rebounds back. Some factors that can skew a test with a rebound hammer include the following. Pdf this study examines the factors affecting the results of nondestructive testing of highstrength concrete performed on cubes and on.
Rebound hammer l rebound hammer test i schmidt hammer i concrete test hammer rebound hammer duration. Pdf reliability of rebound hammer test in concrete. 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 surface. Proceqs schmidt hammer portfolio is the most comprehensive available. Rebound hammer rebound hammer a handy nondestructive testing instrument should be cheap, easy to operate and should have reproducibility for, fairly accurate results. However, in all of these techniques, the rebound hammer test is usually used to conclude the compressive strength of concrete 31. 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. Moreover, we will discuss how to estimate concrete strength using rebound hammer. Before the hammer can be used for testing, the piston must be released out of. Case study of strength evaluation of structural 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. Rebound hammer test is done to find out the compressive strength of concrete by using rebound hammer as per is. These versatile concrete testing tools, also called swiss hammers or rebound hammers.
Rebound hammer test is a nondestructive testing method of concrete which provide a convenient and rapid indication of the compressive strength of the concrete. Supplied complete with carrying case and carborundum stone, the hammer is suitable for testing concrete with compressive strengths of. Application of rebound hammer method for estimating. Guidebook on nondestructive testing of concrete structures. Procedure for rebound hammer test on concrete structure starts. This article is to discuss the rebound hammer and how to successfully use it to evaluate concrete. In a research presented by sanchez and tarranza, 5 the authors used rebound hammer to test concrete cubes in two groups. Rebound hammer test schmidt hammer testing on concrete. We perform this test only on hardened concrete to determine the. Also, when in use, keep the hammer perpendicular to the surface you are testing with. Rebound hammer test 10 types of factors which effect it. Rebound hammer test rebound hammer test is done to find out the compressive strength of concrete by using rebound hammer as per is. Two factors contribute to the improved performance of this concrete test hammer over its predecessors.
Suitable for finished concrete structures and buildings having strength resistances from 10 to 70 nsq. Concrete rebount test hammers provide a rebound number, or r value, of hardened concrete. Schmidt rebound hammers, concrete test hammers, ndt. Bureau of indian standard did not published any standard for this test upto 1991. The rebound hammer test is not intended as a substitute for standard compression test, but as a method for determining the uniformity of concrete in the structure and comparing one concrete with another. Cgoldenwall concrete rebound hammer tester resiliometer. The device is to be used exclusively on the surfaces to. Pdf on jan 1, 2014, nathaniel tarranza and others published reliability of rebound hammer test in concrete compressive strength. 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. Schmidt hammer test or rebound hammer test of concrete.
The rebound schmidt hammer is one of the oldest and best known methods of comparing the concrete in various parts of a structure and indirectly assessing concrete strength. However, using these strength curves to predict the compressive strength of carbon fiberreinforced concrete cfrc, polypropylene fiberreinforced concrete pfrc, and carbonpolypropylene hybrid. Concrete should be tested only after it has thawed. It was invented by ernst schmidt, a swiss engineer. Low impact manual test hammers provide the most economical, quick and easy concrete compressive strength test in the field for concrete specimens below 100 mm 4 inch thickness, as well as rock core testing. Reliability of rebound hammer test in concrete compressive. The rebound of an elastic mass depends on the hardness of the surface against which its mass strikes. Only rebound hammer that provides a test result at. Pdf assessing concrete strength with rebound hammer. Rebound hammer test procedure for concrete hardness. Hammer test should be supplemented by core sampling and testing. Rebound hammer test is the most appropriate and useful testing methods for comparing the relatively weaker and stronger areas of concrete. Correlation between schmidt hammer and destructive.
Gupta, niharika gupta and amandeep singh one of the most widely spread techniques to estimate the compressive strength of concrete is the rebound hammer test, also known as schmidt hammer test. Revised rebound hammer and pullout test strength curves. Using the humboldt concrete rebound hammer always hold the concrete rebound hammer in both hands while in use. Standard test method for rebound number of hardened concrete. The rebound hammer test is codified in astm c805 3 and csn en 125042 4. Concrete test hammers are ideal for fast and economical nondestructive testing ndt assessment of inplace concrete strength consistency. A group of cubes was cured by immersing continuously in brackish water. The test is based on the principle that the rebound of an elastic mass depends on the hardness of the surface against which the mass impinges.
It will also provide an indices of hardness and compressive strength for other construction materials, such as ceramics, and tile. Concrete test hammers swiss precision since 1954 the concrete test hammers are the most widely used portable ndt measuring instruments for a rapid assessment of the condition of a concrete structure. The rebound the rigidity of the test area hammer measures the surface hardness of the age of the concrete concrete. Concrete rebound hammer concrete test rebound hammer. The main reason behind its popularity is its simplicity, and convenience of use for field. 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. Review of the rebound hammer method estimating concrete.
Proper use of the rebound hammer updated to reflect the. 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 concrete test hammer invented by ernst schmidt and introduced by proceq at the beginning of the 1950s remains to this day the most. The rebound depends on the surface hardness of the concrete and is measured by test equipment. Mentioned are the principle, procedure, advantages and disadvantages of rebound hammer. Rebound hammer test on concrete principle, procedure. Smoothness of a concrete surface moisture content type of course aggregate size, shape, and rigidity of specimen. Basically, this is a surface rigidity test and it also works on.
1271 596 1375 40 393 1493 228 1217 143 1140 625 175 169 452 1112 10 825 1104 931 420 67 186 1407 362 966 966 1222 453