rebound hammer test report

In cases the quality of concrete assessed by UPV is doubtful no assessment of concrete strength shall be made from the rebound hammer test. Pushing test hammer on end cover slowly the hammer was unlocked and the button was bound out stop.

The results are corrected to a horizontal or vertical position using the correction curves provided by the manufacturer.

. 2 The time required for the testing is 10 to 20 seconds. B Identification of the concrete structureelement. The force causes the latch.

Test Report The report shall include the following. 74 shows a series of empirically determined curves relating the L-type Schmidt hammer rebound number at different. For each point take 3 readings on each of the 4 moulded faces without testing the same spot twice.

Firstlythe test hammer was unlocked before a test and kept the rebound pole perpendicular to a surface any hard. For obtaining the test result using the rebound hammer following steps were followed. This is accomplished by placing the rebound hammer plunger against the concrete surface and releasing a spring loaded weight.

SCHMIDT HAMMER REBOUND TEST. The rebound hammer is a nondestructive testing apparatus whereby the rebound of the spring driven mass is measured after its impact with concrete surface. One such method that has found practical application with a limited scope is known as the Rebound Hammer Test devised by Ernst Schmidt.

The method may be compared to dropping a large ball-bearing onto a concrete surface. 9142 Orientation of hammer during test 915 Average rebound number for test area and 9151 Remarks regarding discarded readings of test data or any unusual conditions. Rebound Hammer test is a Non-destructive testing method of concrete which provide a convenient and rapid indication of the compressive strength of the concrete.

It can be derived from slope of stress-strain diagram. Parts of the Schmidt Hammer Parts of the hammer are shown in figure below. Concrete surfaces are thoroughly cleaned before taking any measurementaround each point of observation six readings of rebound indices are taken and average of thesereadings after deleting outliers as per is8900-1978.

Shall be removed before testing. C Location of test area s. 70 engineering judgment and concluding the hammer must be held in the same.

150 mm cube specimens are preferred for calibrating rebound hammers of lower impact energy 22 Nm whereas for rebound hammers of higher impact energy for example 30 Nm the test cubes should not be. Block-1 Block-2 Block-4 Block-5 Block-7 Block-8 Block-9 Block-10. STEPS 1 Make 15 hammer rebound readings per floor using tape and centre point 5 on each of 3 vertical lines 120 apart against the side surface in the middle two thirds of each cylinder.

Additional investigations would need to be done if the layer of carbonated concrete is thick it by the engineer. This rebound number is shown on a scale and will be between 10 and 100. The rebound hammer measures the surface hardness of the concrete.

If the surface is very rigid ie high modulus the ball bearing would be expected to bounce back to a. ASTM C805 Standard Test Method for Rebound Number of Hardened Concrete summarizes the procedure as A steel hammer impacts with a predetermined am ount of. A Dateperiod of testing.

The test procedure includes the following series of steps. The Schmidt hammer rebound test has been briefly described in Chapter 3. Various empirical correlations have been proposed for estimating the unconfined compressive strength of rocks from the Schmidt hammer rebound number.

If the rebound the surface to be tested must be free from numbers in the area being tested were lower then water. After the rebound hammer impact press the button was pressed and the test hammer was lock. The test specimens should be as large a mass as possible in order to minimise the size effect on the test result of a full-scale structure.

It weighs about 4 lbs and is suitable for use in laboratory and in the field. 3 Temperature and humidity affects the result. Finally at the end of the test rebound pole was pushed back into the test hammer just like above test procedure.

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. 1 It does not give yield point in metals. Rebound hammer test is conducted around all the points of observation on all accessible faces ofthe structural element.

Among the NDT procedures the rebound Schmidt hammer test is largely used in common engineering practice because of its simplicity and the low price of the equipment. The test was continued at other test points. It is also known as impact hammer or Sclerometer test.

The rebound hammer is first calibrated. The rebound hammer often a Schmidt hammer measures the rebound of a weight from the back of an anvil pushed against the concrete surface. The reliability of the test is still substantially unknown thus opening the way to a.

Botswana International University of Science and Technology. TENSILE AND COMPRESSIVE STRENGTHS OF ROCKS. Hold the Rebound Hammer at right angles to the test surface with the plunger pin pointing towards the test location Push the plunger against the concrete and force the cylinder body towards the concrete.

The amount the plunger rebounds or bounces back is measured. 4 It is time-consuming and require more skill to obtain results. There are following disadvantages in rebound hammer test.

The output of the rebound hammer is referred to as rebound number and are correlated with surface hardness of. For tests conducted in situ on a rock mass the rebound hammer can be used at any desired orientation provided the plunger strikes perpendicular to the surface tested. The calibration is done by testing the hammer against an anvil that is made up of steel whose Brinell hardness number is 5000 Nmm².

Avoid testing the same spot twice. Precision and Bias 101 PrecisionThe single-specimen single-operator ma-chine day standard deviation is 25 units 1s as deﬁned in Practice E 177.

Rebound Hammer Test Of Concrete Procedure Applications

Case Study Of Strength Evaluation Of Structural Concrete Using Rebound Hammer Test Semantic Scholar