The testing anvil should be of steel having brine11 hardness of about 5 000 nmms. The shore scleroscope, ass mentioned before, measures the rebound hardness of a material, and depends on the resilience of the hammer for consistent results. Put the rebound hammer back together, and test it on the anvil again to get a calibrated reading. Rebound hammer test is also called a schmidt hammer test that consists of a spring controlled mass that slides on a plunger within a tubular. Ultrasonic pulse velocity test services and rebound hammer. Temperature of the rebound hammer itself may affect the rebound number. The suitable methods for checking the calibration of the rebound hammer is to test the concrete cube of size 150mm 150mm 150mm with the help of rebound hammer. Rebound hammer for non destructive testing of concrete. When used in any other position, appropriate correction as given by the manufacturer is to be taken into account. Typically, a rebound hammer will result in a rebound number of. The rebound of an elastic mass depends on the hardness of the surface against which its mass strikes. The concept of this method is to correlate the surface hardness of the concrete surface to the compressive strength of the concrete. However, it typically has the largest coefficient of variation.
Introduction the rebound hammer test is the most popular method to measure the surface hardness of a. Lab report4989259 lab report for construction materials concrete. 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 underlying principle of the rebound hammer test is. Concrete strength test rebound hammer original schmidt live. Impact energy for rebound hammer for different applications. It is necessary to calibrate the rebound hammer before carrying out the test on hardened concrete. The aim of rebound hammer tests is usually to find a relationship between surface. The rebound hammer test, which is also widely known as schmidt hammer test, is one of the most commonly used nondestructive tests for hardened concrete.
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. Description a rebound hammer provides a method for. The manufacturer shall report the rebound number to be obtained by a properly operating instrument when tested on an. The rebound hammer strength test, being a nondestructive test, has its. Since the test is very sensitive to the presence of aggregates and voids at the concrete surface, it is necessary to take more than 10. Rebound hammer rebound hammer test is done to find out the compressive strength of concrete by using rebound hammer as per is. The rebound hammer strength test, being a nondestructive test, has its advantages of preserving integrity of sample. Lab report4989259 lab report for construction materials. Nondestructive testing of concrete methods of test. Estimate concrete strength using rebound hammer fprimec. The hammer and materials to be tested should be at the same temperature.
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 scmidt hammer test is based on the elastic rebound of hammer which presses on concrete surface and it measures the surface hardness of concrete. The position of the mass relative to the vertical, however. Some factors that may affect the results of the test include. 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. Test procedure is simple and equipment is portable and easy to operate.
The test can thus be conducted horizontally on vertical surfaces or vertically upwards or downwards on horizontal surfaces. Rebound hammer test is a nondestructive testing method of concrete which provide a convenient and rapid indication of the compressive strength of the concrete. The rebound hammer test is one of the nondestructive tests used to check the compressive strength of concrete. An empirical relationship has been determined between the a absorbed by the concrete when given a high impact and its compressive. Bureau of indian standard did not published any standard for this test upto 1991. Rebound hammer is a springloaded steel hammer that, when released, strikes a steel. 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. In the united states, the two most commonly used tests are the brinell and rockwell tests. Rebound hammer test schmidt hammer testing on concrete. Standard test method for determination of rock hardness by. To carry out this experiment, apparatus like rebound hammer is needed. Rebound hammer test nondestructive testing hardness. Schmidt hammer test or rebound hammer test of concrete.
Digital rebound test hammer, concrete testing equipment. Schmidt hammer test report of samundratar bridge nuwakot, bagmati. Besides, the test is relative simple, economical and versatile compared to conventional crushing tests. Fresh concrete test workability apparatus slump test. 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. Ndt lab manual page 1 chapter 1 determine ompressive strength of concrete by using manual rebound schmidt hammer 1. Standard test method for rebound number of hardened. Rebound hammer test procedure for concrete hardness. The rebound hammer test has been around since 1940s and today is a commonly used method for estimating the compressive strength of in place concrete.
If concrete compression test fails, should schmidt hammer. In such cases the member has to be rigidly held or backed up by a heavy mass. When the plunger of rebound hammer is pressed against the surface of the. Rebound test hammer digital model 58c0181dgt rebound digital test hammer supplied complete with case model 58c0181dgt rebound test hammer digital model 58c0181dgt with accessories example of digital hammer screen display main manu example of digital hammer screen display selectable standard example of digital hammer screen display measurement and indication of 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 original schmidt os8000 is the original concrete test hammer, now digitally redefined and it is also the most advanced rvalue hammer ever made, with unmatched performance, ease of use, and versatility, as well as reporting on the go thanks to its mobile app. Rebound hammer l rebound hammer test i schmidt hammer i. The method is widely used for testing concretes manufacturers of such rebound hammers usually provide calibrated curves showing the relation of compressive strength and. Keep adjusting and testing the rebound hammer until it. In this article, we describe how to estimate concrete strength using rebound hammer. Concrete rebound hammer original schmidt os8000 less coring, with concrete strength and uniformity evaluation using rebound hammer technology schmidt hammers by proceq, the inventor of rebound hammer technology, have long been the global benchmark for nondestructive compressive strength estimation, and make it possible to drastically.
Report of rebound hammer test concrete applied and. For taking a measurement, the rebound hammer should be held at right angles to them surface of the concrete member. The instrument firmly held perpendicular to the test surface and gradually pushed toward the test surface until the hammer impact. Lab report gis and rs 2012ge56 16 if the concrete does not form part of a large mass any movement caused by the impact of the hammer will result in a reduction in the rebound number. 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 of an elastic mass depends on the hardness of. The principles on which it works are based on the rebound impact of a hammer on a piston which rests against the surface of the concrete under test. Guidebook on nondestructive testing of concrete structures. Ucs test and triaxial point load index test schmidt rebound. The rebound hammer strength test, being a nondestructive test. If the readings fall outside of this range, take the rebound hammer apart and try to adjust it again.
To find the quality of concrete in relation to standard requirement. Rebound hammer test is done to find out the compressive strength of concrete by using rebound hammer as per is. Review of the rebound hammer method estimating concrete. The hammer can be used in the horizontal, vertically overhead or vertically downward positions as well as at any intermediate angle, provided the hammer is perpendicular to the surface under test. 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. Result from rebound hammer test sometimes also influence by person who carried out the test. Schmidt rebound hammers, concrete test hammers, ndt.
The schmidt hammer rebound test was developed to determine the compressive strength of concrete, and has been used to determine the hardness and compressive strength of rock material isrm 1978a. The rebound is read off along a graduated scale and designation as the rebound number of rebound index. Lab manual rebound hammer concrete strength of materials. Application of rebound hammer method for estimating. Nondestructive testing of concrete by rebound hammer. Rubene and vilnitis performed a series of laboratory tests and found. Rebound hammer test on concrete principle, procedure. The bridge is a 35m long span bridge which connects samundratar vdc 5 and 6. Rebound hammer test is the most appropriate and useful testing methods for comparing the relatively weaker and stronger areas of concrete. Test can be undertaken on site and the number of test is unlimited. Moreover, the best part of rebound hammer test is concrete can be tested in real time at the site instead of going to the lab without any damage. Rebound hammer test is a nondestructive ndt test of concrete and simple concrete test which is used to test the compressive strength of concrete without any damage.
102 515 613 1450 487 653 421 677 214 104 215 1047 607 163 384 1292 961 968 46 369 235 875 997 614 793 472 1405 1505 1395 286 346 1461 130 630 793 859 765 897 217 1199