Rebound hammer conversion in excel concrete engineering. The final results showed an acceptable accuracy of the calibration curve in the prediction of the compressive strength of re material. To carry out this experiment, apparatus like rebound hammer is needed. Testing the strength of concrete without destructing or breaking it after hardening is a complex task. 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. 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.
Estimating the strength of concrete using surface rebound. Schmidt hammer test report of samundratar bridge nuwakot, bagmati. When used in any other position, appropriate correction as given by the manufacturer is to be taken into account. Description a rebound hammer provides a method for. Does anyone have an excel conversion for rebound hammer test. Rebound hammer test 10 types of factors which effect it. Introduction the rebound hammer test is the most popular method to measure the surface hardness of a concrete mass. The underlying principle of the rebound hammer test is. The schmidt hammer is an arbitrary scale ranging from 10 to 100. 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.
Yasar and erdogan 2004a derived the following empirical correlation between them based on the test results of six different rock types. Schmidt type n hammers are ideal for concrete strengths. C805 c805m18 standard test method for rebound number of hardened concrete rebound number insulating boards springdriven steel hammers. Ceyhan limestone, barbaros marble, antique cream limestone, osmaniye marble, toprakkale basalts, and handere sandstone. Doc rebound hammer test result prince patwa academia. 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. Rebound hammer test procedure for concrete hardness. Rebound hammer test is done to find out the compressive strength of concrete by using rebound hammer as per is. Nondestructive testing of concrete methods of test. Rebound hammer test is a nondestructive testing method of concrete which provide a convenient and rapid indication of the compressive strength of the concrete. All concrete test hammers measure the surface hardness of the material they are testing. Does aci recommend any other nondestructive testing ndt method for inplace strength evaluation.
Rebound hammer rebound hammer a handy nondestructive testing instrument should be cheap, easy to operate and should have reproducibility for, fairly accurate results. Rebound hammer test schmidt hammer testing on concrete. Around each point of observation, six readings of rebound. Note the rebound hammer method can be used with greater confidence for differentiating between the questionable and acceptable parts of a structure or for relative comparison between two different structures. Pdf reliability of rebound hammer test in concrete. While most journal articles have positive results, some also have concluded that the rebound hammer test does not give accurate results concerning the strength of concrete due to various factors. Reliability of rebound hammer test in concrete compressive. Developed in 1948 by a swiss engineer named ernst schmidt, the device measures the hardness of concrete surfaces. Destructive tests can provide direct information, but are relatively expensive, time. Then the compressive strength was ascertained on a pressure testing machine. Rating is available when the video has been rented. The bridge is a 35m long span bridge which connects samundratar vdc 5 and 6.
Rebound hammer test is conducted around all the points of observation on all accessible faces of the structural element. Rebound hammer is also known as schmidts hammer or swiss hammer as it is invented by ernst schmidt, a swiss engineer. Test procedure is simple and equipment is portable and easy to operate. Rebound hammer test, schmidt hammer test, nondestructive.
Rebound hammer is a very simple apparatus to work with. Schmidt hammer test or rebound hammer test of concrete. Preparing test surface inspectors should pay attention to the following considerations prior to conducting a rebound hammer test. How to do rebound hammer test to check compressive. 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 rebound of an elastic mass depends on the hardness of the surface against which its mass strikes. This article is to discuss the rebound hammer and how to successfully use it to evaluate concrete. Review of the rebound hammer method estimating concrete.
Pdf rebound hammer test method statement rusi sumdaram. Destructive and nondestructive testing ndt techniques are applied. 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 of an elastic mass depends on the hardness of.
Around each point of observation, six readings of rebound indices are taken and average of these. The rebound hammer strength test, being a nondestructive test, has its advantages of preserving integrity of sample. 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. Rebound hammer is a springloaded steel hammer that, when released, strikes a steel. Ectha pro concrete test hammer is the result of over 30 years of mechanical manufacturer. Application of rebound hammer method for estimating. Pdf field identification of bricks by rebound hammer test. Assessing the rebound hammer test for rammed earth.
Concrete laboratary instruction manual for iv semester b. The test can thus be conducted horizontally on vertical surfaces or vertically upwards or downwards on horizontal surfaces. We perform this test only on hardened concrete to determine the hardness of the surface and its strength. 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. Test can be undertaken on site and the number of test is unlimited.
Standard test method for rebound number of hardened concrete1. 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. Put the rebound hammer back together, and test it on the anvil again to get a calibrated reading. 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. Pdf the rebound hammer strength test, being a nondestructive test, has its advantages of preserving.
The basic features of this equipment are shown in figure 1 below. The rebound hammer is also one of the easiest pieces of equipment to misuse. The functionality of the rebound hammer shall have been verified in accordance with 6. In 1948, a swiss engineer, ernst schmidt developed a test hammer for measuring the hardness of concrete by the rebound. Ectha pro is made up of a mechanical model n rebound hammer with the. Silverschmidt type l with a mushroom plunger is often utilized to measure the asphalt strength of newly built and repaired roads before opening them. Schmidt hammer rebound number is higher as density or unit weight increases. Besides, the test is relative simple, economical and versatile compared to conventional crushing tests.
Estimate concrete strength using rebound hammer fprimec. Use type n rebound hammers that are commercially available. This device is universally used because of a hardened steel hammerimpacted on the concrete by a spring. The swiss engineer ernst schmidt first developed a practicable rebound test hammer. Nondestructive testing of concrete by rebound hammer.
But the analysis and interpretation of results are not so easy. Rebound hammer test method is based on the principle that the rebound of an elastic mass depends on the hardness of the concrete surface against which the mass strikes. Rebound hammer conversion in excel motorcity structural 20 nov 17 18. Bureau of indian standard did not published any standard for this test upto 1991. Report of rebound hammer test concrete applied and. The manufacturer shall report the rebound number to be obtained by a properly operating instrument when tested on an anvil of specified hardness. Central to the improvement of the concrete infrastructure are tools that evaluate the condition of existing construction. Standard test method for rebound number of hardened. Concrete surfaces are thoroughly cleaned before taking any measurement. Principles of the rebound hammer ernst schmidt, a swiss engineer, developed the modern rebound hammer in 1948. Rebound hammer test is the most appropriate and useful testing methods for comparing the relatively weaker and stronger areas of concrete. In each test, at least 10 test hammer impacts were performed on one. Rebound hammer against the concrete surface to be tested.
I do not have any excel spreadsheets for a rebound hammer test, but others may be able to help if you indicate what information you are trying to convert for a rebound hammer test. Hammer tests can help find good candidates for concrete test samples and evaluate damaged concrete. Description a rebound hammer provides a method for assessing the insitu. 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. This makes your test results easier to read, as it will also lock the indicator. 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 document is available in pdf format, available for download in. Laboratory manual imam abdulrahman bin faisal university. Typically, a rebound hammer will result in a rebound number of 80 2 when. Guidebook on nondestructive testing of concrete structures. Pdf the present study is aimed to establish the nondestructive rebound hammer test for identification. Proceqs schmidt hammer portfolio is the most comprehensive available.
James instruments specalises in nondestructive testing equipment for concrete and other construction materials. Astm c805 c805m 18 standard test method for rebound. 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. Standard test method for rebound number of hardened concrete. Rebound hammer test, which is also called as the schmidt hammer test. The method is widely used for testing concretes manufacturers of such rebound hammers usually provide calibrated curves showing the relation of compressive strength and. The investigation was conducted on 150mm concrete cubes which were cured for 28 days before the exposures. Rebound hammer test rebound hammer test is done to find out the compressive strength of concrete by using rebound hammer as per is. Ltd anamnagar, kathmandu may, 2015 introduction the proposed samundratar bridge is under construction at samundratar vdc. The rebound reading will be affected by the orientation of the hammer, when used in a vertical position on the underside of a suspended slab for example gravity will increase the rebound distance of the mass and vice versa for a test conducted on a floor slab.
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