Rebound hammer might provide some information on concrete quality provided that it is calibrated on. 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. It is necessary that the rebound hammer is checked against the testing anvil before commencement of a test to ensure reliable results. The underlying principle of the rebound hammer test is.
Around each point of observation, six readings of rebound indices are taken and average of these. 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. Introduction the rebound hammer test is the most popular method to measure the surface hardness of a concrete mass. The swiss engineer ernst schmidt first developed a practicable rebound test hammer. Estimating the strength of concrete using surface rebound.
Nondestructive testing of concrete by rebound hammer. A number in parentheses indicates the year of last. The final results showed an acceptable accuracy of the calibration curve in the prediction of the compressive strength of re material. The test can thus be conducted horizontally on vertical surfaces or vertically upwards or downwards on horizontal surfaces. Destructive tests can provide direct information, but are relatively expensive, time. Using the humboldt concrete rebound hammer always hold the concrete rebound hammer in both hands while in use. Then the compressive strength was ascertained on a pressure testing machine. The manufacturer shall report the rebound number to be obtained by a properly operating instrument when tested on an anvil of specified hardness. Nondestructive testing of concrete methods of test. Ceyhan limestone, barbaros marble, antique cream limestone, osmaniye marble, toprakkale basalts, and handere sandstone. Rebound hammer test schmidt hammer testing on concrete. The rebound hammer is generally unsuitable for very soft or very hard rock.
Yasar and erdogan 2004a derived the following empirical correlation between them based on the test results of six different rock types. The schmidt rebound hammer is basically a surface hardness test with little apparent. Report of rebound hammer test free download as word doc. The detailed rebound hammer test was done for the newly under construction tpo cell building. The rebound hammer strength test, being a nondestructive test, has its advantages of preserving integrity of sample. Asphalt strength testing with a rebound hammer although the silverschmidt is mainly used to verify concrete compressive strength, it can also be employed in the verification of other materials. The basic features of this equipment are shown in figure 1 below. Central to the improvement of the concrete infrastructure are tools that evaluate the condition of existing construction. Rebound hammer test on concrete principle, procedure. Rebound hammer test is the most appropriate and useful testing methods for comparing the relatively weaker and stronger areas of concrete. Constructed structures have to be investigated for evaluating the serviceability and safety from time to time.
Rebound hammer is a springloaded steel hammer that, when released, strikes a steel. Rebound hammer is also known as schmidts hammer or swiss hammer as it is invented by ernst schmidt, a swiss engineer. C805 c805m18 standard test method for rebound number of hardened concrete rebound number insulating boards springdriven steel hammers. Principles of the rebound hammer ernst schmidt, a swiss engineer, developed the modern rebound hammer in 1948. Moreover, results show that in each of the three groups, the average estimated compressive strength of concrete based on schmidt. Bureau of indian standard did not published any standard for this test upto 1991. Schmidt hammer test, hammer rebound, ultra sonic test, pulse velocity, core samples, compression strength, combined method, statistical analysis. The most recent results of scientific research show that the.
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. Case study of strength evaluation of structural concrete. Proper use of the rebound hammer updated to reflect the. If the situation demands,the rebound hammer can be held at intermediate angles also, but in each case, the rebound number will be different for the same concrete. Schmidt rebound hammers, concrete test hammers, ndt. Silverschmidt type l with a mushroom plunger is often utilized to measure the asphalt strength of newly built and repaired roads before opening them. Laboratory manual imam abdulrahman bin faisal university.
Pdf the rebound hammer strength test, being a nondestructive test, has its advantages of preserving integrity of sample. In addition, influence of test conditions and some general guidance on the interpretation of test results are also given. Study of concrete quality assessment of structural. Besides, the test is relative simple, economical and versatile compared to conventional crushing tests. Standard test method for determination of rock hardness by rebound hammer method1 this standard is issued under the. Estimate concrete strength using rebound hammer fprimec. Testing the strength of concrete without destructing or breaking it after hardening is a complex task. Standard test method for determination of rock hardness by. The surface of hardened concrete is struck with the hammer, and concrete compressive strength is estimated via the surface hardness rebound value.
Pdf application of rebound hammer method for estimating. Study of concrete quality assessment of structural elements using. Standard test method for rebound number of hardened. Destructive and nondestructive testing ndt techniques are applied. Application of rebound hammer method for estimating compressive. Schmidt hammer test or rebound hammer test of concrete. Application of rebound hammer method for estimating. Assessing the rebound hammer test for rammed earth.
The rebound reading on the indicator scale has been calibrated by the manufacturer of the rebound hammer for horizontal impact, that is, on a vertical surface, to indicate the compression strength. Obtaining reliable compressive strength estimations with a. Schmidt hammer rebound number is higher as density or unit weight increases. Around each point of observation, six readings of rebound. Put the rebound hammer back together, and test it on the anvil again to get a calibrated reading. Concrete inspection rebound hammer elcometer 181 analogue concrete test hammer standards. This article is to discuss the rebound hammer and how to successfully use it to evaluate concrete. Only rebound hammer that provides a test result at compressive strengths below 5 mpa.
Report of rebound hammer test concrete applied and. 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. Rebound hammer test is conducted around all the points of observation on all accessible faces of the structural element. Review of the rebound hammer method estimating concrete. Case study of strength evaluation of structural concrete using rebound hammer test gupta pk, gupta n, singh a, the indian concrete journal, 2015. The rebound hammer is also one of the easiest pieces of equipment to misuse. Doc rebound hammer test result prince patwa academia. The rebound of an elastic mass depends on the hardness of the surface against which its mass strikes. Standard test method for rebound number of hardened concrete. Reliability of rebound hammer test in concrete compressive. It is one of the most useful non destructive techniques in evaluation of concrete structures. Rock is scratched very soft with a fingernail and peeled with a pocket knife. In each test, at least 10 test hammer impacts were performed on one. Procedure for rebound hammer test procedure for rebound hammer test on concrete structure starts with calibration of the rebound hammer.
Concrete surfaces are thoroughly cleaned before taking any measurement. As we already discussed the compressive strength of concrete by concrete cube test which is a destructive test worked out in the lab. 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. To carry out this experiment, apparatus like rebound hammer is needed. 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 consisting of a letter giving an indication of the quality of the concrete and a number giving indication on the. Rebound hammer test procedure for concrete hardness. Preparing test surface inspectors should pay attention to the following considerations prior to conducting a rebound hammer test. Rebound hammer test rebound hammer test is done to find out the compressive strength of concrete by using rebound hammer as per is.
Pdf rebound hammer test method statement rusi sumdaram. Standard test method for rebound number of hardened concrete1. Also structures which are suspected to any strength failure are. James instruments specalises in nondestructive testing equipment for concrete and other construction materials.
All concrete test hammers measure the surface hardness of the material they are testing. For this, the rebound hammer is tested against the test anvil made of steel having brinell hardness number of about 5000 nmm2. Simple field tests are conducted to quickly assess a rock materials suitability for the rebound hammer test method. The results obtained from rebound hammer test and actual compressive. Also establish the interference for the location of readings of rebound hammer. The hm75 schmidt concrete rebound test hammer provides rapid nondestructive estimates of inplace concrete strength and is a valuable tool when assessing the need for further testing. Note in view of the limitations of each method of nondestructive testing of concrete, it is essential. Developed in 1948 by a swiss engineer named ernst schmidt, the device measures the hardness of concrete surfaces. The functionality of the rebound hammer shall have been verified in accordance with 6.
This makes your test results easier to read, as it will also lock the indicator. The rebound of an elastic mass depends on the hardness of. The method is widely used for testing concretes manufacturers of such rebound hammers usually provide calibrated curves showing the relation of compressive strength and. Schmidt hammers, or concrete test hammers, are used to determine inplace strength of concrete. Rebound hammer is a very simple apparatus to work with. The rebound values r of the sample cubes were measured using the concrete test hammer. Guidebook on nondestructive testing of concrete structures. Statistical case study on schmidt hammer, ultrasonic and. Pushing test hammer on end cover slowly, the hammer was unlocked and the button was bound out, stop pushing, removing the test hammer away from the surface, rebound pole was reach out, and at the same time the rebound hammer was hooked because of the pushing from compression spring, then it was ready for a test. Typically, a rebound hammer will result in a rebound number of. When used in any other position, appropriate correction as given by the manufacturer is to be taken into account.
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