To perform a test, make sure the piston is extended and gently press the rebound hammer against the concrete surface to be tested. Rebound hammer test regression analysis for strength versus rn the rebound hammer test is based on the surface hardness of concrete. Application of rebound hammer method for estimating. Although the intrinsic limitations of the test may result in large variations in the estimated strength, ease of conducting the test and low initial cost has made the test quite. A simple equipment known as rebound hammer or schmidt hammer is used for this purpose. Rebound hammer is unable of giving a reliable estimate of the concrete. Nondestructive schmidt rebound hammer evaluation of the. The original schmidt, the worlds first and now most widely used test hammer for.
Rebound hammer rebound hammer a handy nondestructive testing instrument should be cheap, easy to operate and should have reproducibility for, fairly accurate results. Concrete rebound hammer concrete test hammer, ideally suited for onsite tests of concrete and is widely used instrument for analyzing the uniformity and compressive strength characteristics of concrete structures and detection of weak spots in the concrete. It is a field test non destructive test test consists of impacting a wall with a hammer blow and measuring the travel time of a sonic wave across a gage distance to measure the velocity it is used to asses the condition of masonry i. 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. Perform a few test impacts with the concrete test hammer on this smooth, hard sur face before taking any measurements which you are going to evaluate. Proceqs schmidt hammer portfolio is the most comprehensive available.
Schmidt rebound hammer test pdf concrete structures through a series of tests using a rebound hammer and concrete cube destructive. 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. An astm designation number identifies a unique version of an astm standard. Although many experimental results have shown that. Active standard astm c805 c805m developed by subcommittee. Use type n rebound hammers that are commercially available to. Rebound hammer is a nondestructive testing for rcc structures,basically to analyse insitu compressive strength of concrete. The test can thus be conducted horizontally on vertical surfaces or vertically upwards or downwards on horizontal surfaces. Analysis of impact hammer rebound to estimate rock. The underlying principle of the rebound hammer test is. The rebound hammer should be considered as a means of determining variations of strength within a structure rather than an accurate means of assessing strength.
Rebound hammer test measures the surface hardness of concrete with approximate correlations to estimate the compressive strength of the structure. Ideal for fast and nondestructive estimations of concrete strength. Rebound hammer test, standard test method for rebound number of hardened concrete astm c 805, all civil engineering experiments online on civilengineerspk. Lai research fellow, department of civil and structural engineering, hk polyu visiting scientist, federal institute of materials res. Testing services rebound hammer rebound hammer test is done to find out the compressive strength of concrete by using rebound hammer as per is. Besides, the test is relative simple, economical and versatile compared to conventional crushing tests. Rebound hammers test the strength of inplace concrete in a nondestructive way. To perform a test, make sure the piston is extended and gently press the.
In hammer impact testing modal testing we use a special hammer with a load cell in its tip to measure the force of the impact. 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. Pdf field identification of bricks by rebound hammer test. This device is universally used because of a hardened steel hammerimpacted on the concrete by a spring. You will hear a click, and the piston will extend into the test position. Nondestructive testing of concrete methods of test. Astm c805, standard test method for rebound number of hardened concrete, summarizes the procedure as a steel hammer impacts, with a predetermined. Rebound hammer types free download as powerpoint presentation. Astm c805 c805m 18 standard test method for rebound. Always hold the rebound hammer with both hands perpendicular to the surface figure 1. Rebound hammer test at heavener hall performed on 091120. Supplied complete with carrying case and carborundum stone, the hammer is suitable for testing concrete with compressive strengths of. Surface hardness measured during the test give an idea about the soundness and quality of cover concrete. The surface of hardened concrete is struck with the hammer, and concrete compressive strength is estimated via the surface hardness rebound value.
This might be done by taking cores, visual inspection andor by a structural evaluation of the impact of a low strength concrete in this particular area. Rebound hammer consisting of a springloaded steel hammer that when released strikes a steel plunger in contact with the concrete surface. The test makes it possible to learn the strength of impact, which depends on the resistance of the agglomerate in the absence of large inert lumps or clusters of sand or gravel. Rebound hammer testing provides only an approximate indication of concrete quality and is regarded as a supplementary, inplace technique for estimating compressive strength in castinplace concrete.
The test hammer may be used for nondestructive control on cement during the normal construction of factories and bridges. This easytouse instrument provides a quick and simple test for obtaining an immediate indication of concrete strength in various parts of a structure. Nondestructive evaluation and accreditation of diagnostic tests on concrete scct annual concrete seminar 2012 18 april 2012 ir dr wallace w. In addition it determines strengths between approximately 1,400. All concrete test hammers measure the surface hardness of the material they are testing. Rebound hammer test rebound hammer test is done to find out the compressive strength of concrete by using rebound hammer as per is. Brencich and others published calibration and reliability of the rebound schmidt hammer test find, read and cite all the research you need on researchgate. Schmidt hammer type n rebound hammer certified material. Rebound hammers nondestructive concrete testing equipment. Compressive strength, concrete, high temperature, original schmidt n, rebound hammer, silverschmidt l. Rebound hammer test is done to find out the compressive strength of concrete by using rebound hammer as per is. Schmidt hammer test pdf estimate the compressive strength of concrete is the rebound hammer test, also known as schmidt hammer test.
Pdf calibration and reliability of the rebound schmidt. 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. For taking a measurement, the rebound hammer should be held at right angles to them surface of the concrete member. Prosig hammer test system if you need to perform hammer impact tests also known as bump testing, tap testing, or hammer resonance testing then take a look at the prosig hammer impact test system. Schmidt type n hammers are ideal for concrete strengths. Hammer tests can help find good candidates for concrete test samples and evaluate damaged concrete. Proper use of the rebound hammer updated to reflect the. Estimating the strength of concrete using surface rebound. The research focuses on nondestructive schmidt rebound hammer testing of experimental. Rebound hammer against the concrete surface to be tested. Review of the rebound hammer method estimating concrete. The rebound of an elastic mass depends on the hardness of the surface against which its mass strikes.
The rebound hammer silverschmidt l and original schmidt n was used for determining the. Cube strength results have failed or cube samples have being rejected. Hammer tests help determine where to test cores and locates damage from freezing or fire. Astmd5873 standard test method for determination of.
Rebound values are read from a scale for subsequent calculation of the mean. 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. Pdf the present study is aimed to establish the nondestructive rebound hammer test for identification. It is generally performed in following conditions 1. Pdf the rebound hammer strength test, being a nondestructive test, has its. Assessment of characteristic compressive strength in. Hammer testing findings for solidstate lighting luminaires. Tech structural engineering, civil engineering department, ggits jabalpur m. Assessing the rebound hammer test for rammed earth.
In 1948, a swiss engineer, ernst schmidt developed a test hammer for measuring the hardness of concrete by the rebound principle description the hammer consists of a spring controlled mass that slides on a plunger. The method is widely used for testing concretes manufacturers of such rebound hammers usually provide calibrated curves showing the relation of compressive strength and. Standard test method for determination of rock hardness by. 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. Does aci recommend any other nondestructive testing ndt method for inplace strength evaluation. In concrete, why do we conduct rebound hammer tests. The rebound hammer strength test, being a nondestructive test, has its advantages of preserving integrity of sample. Product details the wm250 manual test hammer is the traditional instrument used for the nondestructive testing of hardened concrete. Nondestructive evaluation and accreditation of diagnostic. This tops anything i have seen in 25 years of roofing duration. In order to promote public education and public safety, equal justice for all, a better informed citizenry, the rule of law, world trade and world peace, this legal document is hereby made available on a noncommercial basis, as it is the right of all humans to. The hammer is intended for testing the quality of concrete in finished structures such as buildings and bridges. Rebound hammer, pulse velocity, and core tests in self.
Standard test method for rebound number of hardened. The rebound of an elastic mass depends on the hardness of. Developed in 1948 by a swiss engineer named ernst schmidt, the device measures the hardness of concrete surfaces. Dirt or other loose material on the surface can be removed using a. Test on a wall rebound hammer area to be cored to test strength. Pdf application of rebound hammer method for estimating. Hammer test 48 44 distribution of the number of leds contained in the luminaires examined in hammer test and the cumulative test time 415.
358 1515 1639 1114 22 1374 53 1013 96 822 1219 94 1105 1398 892 596 1552 279 446 1502 1323 1600 61 1262 6 1267 1551 1118 1009 736 923 629 1324 548 18 764 823 950 865 140 713