The test results on ultrasonic pulse velocity and rebound indices are analysed statistically and plotted as histograms and the lower fractiles of results are taken for assessing the. One point consisting of six readings spread over an area of 1 sq. Roknuzzaman et al application of rebound hammer method for estimating compressive strength of bricks the regression coeffi cient r2 values we re found to be better in case of li near. The ht 225 is comparable with the schmidt hammer, type n, this method of testing is covered by din 1048 and bs1881 part 202, referring to assessment of the rebound hardness of mortar which is directly related to the compressive strengths of the tested material.
Oct 29, 2016 the rebound hammer is also one of the easiest pieces of equipment to misuse. Standard test method for rebound number of hardened. Is schmidt hammer test a standard test for testing. Concrete rebound hammer powerpoint ppt presentations.
A free powerpoint ppt presentation displayed as a flash slide show on. Digital functions allow greater number of test, leading to better quality tests. It is necessary that the rebound hammer is checked against the testing anvil before commencement of a test to ensure reliable results. 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 hammer test is codified in astm c805 3 and csn en 125042 4. Schmidt hammers, or concrete test hammers, are used to determine inplace strength of concrete.
The testing anvil should be of steel having brinell hardness of about 5000 nmm. In each test, at least 10 test hammer impacts were performed on one. Rebound hammer test procedure for concrete hardness. If the rebound hammer is reading high, loosen the adjustment screw counterclockwise away from the cap. The rebound values r of the sample cubes were measured using the concrete test hammer. Destructive tests can provide direct information, but are relatively expensive, time. The rebound hammer strength test, being a nondestructive test, has its advantages of preserving integrity of sample. Sep 19, 2014 rebound hammer test rebound hammer test is done to find out the compressive strength of concrete by using rebound hammer as per is. Rebound hammer test on concrete principle, procedure. Digital test hammers for the quick and easy determination of the strength of concrete, and hardness of construction materials. 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 rebound hammer test is one of the nondestructive tests used to check the compressive strength of concrete. Surface hardness measured during the test give an idea about the soundness and quality of cover concrete. When conducting the test the hammer should be held perpendicular to the surface which in turn should be flat and smooth.
The principle of this test is that when the plunger of rebound hammer is pressed against the surface of the concrete the spring. Central to the improvement of the concrete infrastructure are tools that evaluate the condition of existing construction. To measure homogeneity, uniformity, compactibility and presence of crack or void, thus representing durability of concrete. Carbonation is a serious problem for many reinforced concrete buildings that have been in service for some decades. Rebound hammer sgm lab solutions was established with an aim to serve a wide variety of laboratory and. Schmidt rebound hammer test method is most useful in checking the uniformity of concrete in laboratory as well as in the field. Its rebound is dependent on the hardness of the concrete and is measured by the test equipment. 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.
The rebound hammer test shall be conducted at all those points were upv test has been performed. Rebound hammer is also known as schmidts hammer or swiss hammer as it is invented by ernst schmidt, a swiss engineer. The schmidt hammer test involves hitting the insitu concrete with a springdriven pin at a defined energy, and then the rebound is measured. Rebound hammer test is a nondestructive testing method of concrete which provide a convenient and rapid indication of the compressive strength of the concrete.
This article is to discuss the rebound hammer and how to successfully use it to evaluate concrete. Because of the above limitations, the combined use of these two methods is made in another way. Put the rebound hammer back together, and test it on the anvil again to get a calibrated reading. Astm c805 c805m 18 standard test method for rebound. An empirical relationship has been determined between the a absorbed by the concrete when given a high impact and its compressive. 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. The underlying principle of the rebound hammer test is. A simple equipment known as rebound hammer or schmidt hammer is used for this purpose. A number in parentheses indicates the year of last.
The test can thus be conducted horizontally on vertical surfaces or vertically upwards or downwards on horizontal surfaces. 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. Rebound hammer l rebound hammer test i schmidt hammer i concrete test hammer rebound hammer duration. C805 c805m18 standard test method for rebound number of hardened concrete rebound number insulating boards springdriven steel hammers. Standard test method for determination of rock hardness by. Carbon dioxide in the atmosphere, when it comes into contact with concrete, starts off chemical reactions which tend to reduce the concretes protective effect on its reinforcements. Schmidt rebound hammer test is a most common non destructive test ndt performed on hardened concrete. Testing services rebound hammer rebound hammer test is done to find out the compressive strength of concrete by using rebound hammer as per is. Gmt ht225 is a compact concrete testing hammer, commonly used for testing of strength and hardness of various types of concrete materials. Rebound hammer l rebound hammer test i schmidt hammer i. Carbonation depth determination carbontest, concrete.
Around each point of observation, six readings of rebound. When the plunger of rebound hammer is pressed against the surface of the concrete, the. Rebound hammer test schmidt hammer testing on concrete. Standard test method for rebound number of hardened concrete.
Ndt powerful technique for evaluating exiting concrete structures with regard to their strength and durability apart from assessment and control of quality of hardened concrete without or partial damage to the concrete. The test hammer hits the concrete with a springdriven pin at a defined energy, and then measures the rebound in rebound units. All concrete test hammers measure the surface hardness of the material they are testing. Its rebound is dependent on the hardness of the concrete and is measured by test equipement. Standard test method for rebound number of hardened concrete1 this standard is issued under the. Introduction the rebound hammer test is one of the nondestructive tests used to check the compressive strength of concrete. To estimate strength and hardness of the concrete in the cover region is. 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.
The method is widely used for testing concretes manufacturers of such rebound hammers usually provide calibrated curves showing the relation of compressive strength and. Guidebook on nondestructive testing of concrete structures. When testing the strength of concrete, the concrete test hammer uses a certain elastic force to transit the impact force of an impact hammer to the surface of concrete, its initial kinetic energy redistributes, a part of energy in the form of plastic. Besides, the test is relative simple, economical and versatile compared to conventional crushing tests. Betonprufhammer bedienungsanleitung sclerometre a beton nnr. The rebound hammer is also called as schmidt hammer that consist of a spring controlled mass. The manufacturer shall report the rebound number to be obtained by a properly operating instrument when tested on an anvil of specified hardness. Typically, a rebound hammer will result in a rebound number of 80 2 when tested on the anvil described in section 4. Rebound hammer types free download as powerpoint presentation. Acceptability of rebound hammer test is evaluated by different research works and studies.
Then the compressive strength was ascertained on a pressure testing machine. Nondestructive testing of concrete by rebound hammer. Get info of suppliers, manufacturers, exporters, traders of concrete test hammer for buying in india. Concrete rebound hammer powerpoint ppt presentations powershow. The rebound depends on the surface hardness of the concrete and is measured by test equipment. Schmidt hammer test is a quick method for assessing the quality of concrete based on surface hardness indicated by the rebound number. Evaluation of calculation correlation efficiency as.
Standard test method for determination of rock hardness by rebound hammer method1 this standard is issued under the. Advantages of the latter schmidt impact hammer are. 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. Rebound hammer test is the most appropriate and useful testing methods for comparing the relatively weaker and stronger areas of concrete. 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. 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.
It is generally performed in following conditions 1. The rebound hammer test is one of the nondestructive tests used to check the compressive strength of concrete slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Find powerpoint presentations and slides using the power of, find free presentations research about non destructive test for concrete ppt. Ppt concrete rebound hammer powerpoint presentation. Test recommendation after highlighting critical area in the building next step is to recommend the appropriate test to evaluate the structure which may include nondestructive tests like 1. For this, the rebound hammer is tested against the test anvil made of steel having brinell hardness number of about 5000 nmm2. Does aci recommend any other nondestructive testing ndt method for inplace strength evaluation. Apr 09, 2017 rebound hammer is a nondestructive testing for rcc structures,basically to analyse insitu compressive strength of concrete. Application of rebound hammer method for estimating. Nondestructive testing of concrete methods of test. Doc rebound hammer test result prince patwa academia. A number in parentheses indicates the year of last reapproval.
If it reads 80 2, the rebound hammer is calibrated. Cube strength results have failed or cube samples have being rejected. Main unit gmt ht225, grinding wheel, conversion table. View and download powerpoint presentations on non destructive test for concrete ppt. When you are finished, tighten the adjustment nut to lock the screw in this new position. Rebound hammer conversion in excel concrete engineering. Destructive and nondestructive testing ndt techniques are applied.
The underlying principle of the rebound hammer test is the rebound of an elastic mass depends on the hardness of the surface against which its mass strikes. 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 conversion in excel motorcity structural 20 nov 17 18. The functionality of the rebound hammer shall have been verified in accordance with 6.
Procedure for rebound hammer test procedure for rebound hammer test on concrete structure starts with calibration of the rebound hammer. Ppt on destructive testing and non destructive testing. Rebound hammer test rebound hammer test is done to find out the compressive strength of concrete by using rebound hammer as per is. The rebound of an elastic mass depends on the hardness of the surface against which its mass strikes. The concrete test hammer invented by ernst schmidt and introduced by proceq at the beginning of the 1950s remains to this day the most. Hardness testing practice of concrete exclusively applies nowadays the dynamic rebound surface hardness test ing devices e. Find here online price details of companies selling concrete test hammer. Our calibration services are spread all over the india and overseas also. R7500 concrete test hammer kamekura seiki 40179587.
It was invented by ernst schmidt, a swiss engineer. Rebound hammer test is done to find out the compressive strength of concrete by using rebound hammer as per is. Rebound hammer calibration rebound hammer calibration calibration of rebound hammer is what you will get here at sigma test calibration laboratory. James instruments specalises in nondestructive testing equipment for concrete and other construction materials. 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.
Conforms to astm c805 and other international standards. Silverschmidt type l with a mushroom plunger is often utilized to measure the asphalt strength of newly built and repaired roads before opening them. If the strength of concrete is high, then the rebound number is also high. In concrete, why do we conduct rebound hammer tests. Pdf application of rebound hammer method for estimating. Rebound hammer test is a nondestructive testing method of concrete which provide a convenient and rapid indication of the compressive strength of the. 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. During verification, support the test anvil on a bare concrete floor or slab. Akshay r manohar mtechconstruction technology civil engineering dept. Conducting rebound hammer test as per is 311part2, astm c 805.
Rebound values are read from a scale for subsequent calculation of the mean. 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. Aug 09, 2017 rebound hammer l rebound hammer test i schmidt hammer i concrete test hammer rebound hammer duration. Bureau of indian standard did not published any standard for this test upto 1991. Half cell potential meter test 1rebound hammer test 1. Ppt concrete rebound hammer powerpoint presentation free.
R7500 concrete test hammer kamekura seiki monotaro. Dirt or other loose material on the surface can be removed using a grinding stone prior to the test. Rebound hammer test is a methodology to measures the compressive quality strength of concrete in rebound number scale 0 to 40. The rebound hammer test has been around since 1940s and today. Principles of the rebound hammer ernst schmidt, a swiss engineer, developed the modern rebound hammer in 1948.
1406 766 1612 653 210 1193 1305 1344 560 1289 947 1191 498 1387 376 979 185 748 934 396 1091 1524 1289 1467 1015 1363 1499 1156 557 618 425 1249 1294 1163 1401 381 773 500 823 347 916 679 1200 548 1202 1142