A mobile app that lets you annotate measurements with voice, photos and comments. Generate reports and share them instantly. Access your data from anywhere, anytime.
Versatility
Accurately test the widest range of concrete strength classes. Work with the built-in standards-compliant conversions or your own custom material conversions.
Efficiency
Fully assess an entire test region of concrete in less than 10 minutes—saving you days of laborious effort compared with exclusively using coring.
Schmidt App
The Original, now connected
Free updates & releases
Customer-centric development
Ahead of any other solution
The legendary and the Original Schmidt rebound hammer and its Swiss-made accuracy is now even more flexible and connected. Measure, evaluate and fully report even the most extensive inspection projects within just minutes.
Download the app and explore the state of the art of concrete testing
Free updates & releases
Customer-centric development
Ahead of any other solution
The legendary and the Original Schmidt rebound hammer and its Swiss-made accuracy is now even more flexible and connected. Measure, evaluate and fully report even the most extensive inspection projects within just minutes.
Download the app and explore the state of the art of concrete testing
Schmidt App
Custom materials
Flexibility for all applications
Correlation to custom materials in accordance with major standards
Apply user-defined corrections for carbonation, form factors, …
Flexibility for all applications
Correlation to custom materials in accordance with major standards
Apply user-defined corrections for carbonation, form factors, …
Schmidt App
Compliance to standards
Select standard units and form factors
Hammer verification management according to requirements of major standards
Automated EN13791 test region screening report
Select standard units and form factors
Hammer verification management according to requirements of major standards
Automated EN13791 test region screening report
Schmidt App
Collaboration and easy reporting
Visual report generation using lists, bar charts and statistics
Single and multiple series export in PDF or CSV format
Logbook annotations for full traceability (geolocation, text, images, voice)
Visual report generation using lists, bar charts and statistics
Single and multiple series export in PDF or CSV format
Logbook annotations for full traceability (geolocation, text, images, voice)
Schmidt App
Tech Specs
Workflow features
Voice read-out of each impact (only on iOS®) Logbook with geolocation, audio, image and text annotations Series statistics Single series reporting: PDF, CSV Test-region reporting (multiple series): PDF, CSV, uniformity report, EN13791 characteristic strength report
Display
Any compatible Apple® iOS device (please see App Store for details) Any supported Android™ device (please see Google Play Store for details)
Measurements
Test region reporting Select units, form factor and correlation curves Create your own custom curves Create custom curves databases for your own mixes
Verification features
Options: EN12504-2, Manufacturer's recommendation, JGJ-T23 User reminder when verification check on the anvil is required User guidance for verification procedure
What are the formulae used in the compressive strength correlation curves in the OS8000 and OS8200 rebound hammers?
The formulae applied to determine compressive strength correlation curves for the OS8000 and OS8200 rebound hammers are provided in the Schmidt Hammer Conversion Curve Database referenced below:
The formulae applied to determine compressive strength correlation curves for the OS8000 and OS8200 rebound hammers are provided in the Schmidt Hammer Conversion Curve Database referenced below:
Original Schmidt OS8000 Type N
Curve
Min R
Max R
Unit
Form factor
Equation
Proceq B (14 - 56 day mean)
15
55
N/mm2
150 mm cube
Fck = 1.05 x ( 0.01078R2 + 0.904R - 12.91)
Proceq A (7 days mean)
15
55
N/mm2
150 mm cube
Fck = 1.05 x ( 0.012516R2 + 0.706R - 7.49)
Portland Cement J
15
55
kg/cm2
150 mm cube
Fck = 1.05 x ( 0.133R2 +8.82R - 122)
Early strength J
15
55
kg/cm2
150 mm cube
Fck = 1.05 x ( -0.0803R2 + 20R - 253)
Blast Furnace J
15
55
kg/cm2
150 mm cube
Fck =1.05 x ( 0.2R2 + 1.83R + 22.4)
Averag Curve J
15
55
kg/cm2
150 mm cube
Fck = 1.05 x ( 0.0485R2 + 12.3R - 146)
Characteristic strength R
20
75
N/mm2
150 mm cube
Step function (see below)
The characteristic strength curve is based on the reference table for the screening test provided in the Annex to EN13791. This curve provides a safe estimate with <5% probability of over-estimating the strength.
R value - Strength (N/mm2) 20 to 29 - <10 30 to 32 - 10 33 to 34 - 15 35 to 37 - 20 38 to 39 - 25 40 to 42 - 30 43 to 46 - 37 47 to 48 - 45 49 to 50 - 50 51 to 52 - 55 53 to 56 - 60 57 to 59 - 67 60 to 64 - 75 65 to 68 - 85 69 to 75 - 95
Impact angle conversion is applied to the measured R value before calculation of the compressive strength according to these curves. The impact angle correction is based on this formula:
Rcorr=R +(-a0+R*a1)*sin(angle)
a1+
0.08
a0+
7.1
a1-
0.043
a0-
4.3
Take a0+ and a1+ for angles >= 0°, a0- and a1- for angles < 0°
2. Silver Schmidt OS8200 Type N
Curve
Min Q
Max Q
Unit
Form factor
Equation
< 10% (old)
22
75
N/mm2
150 mm cube
fck = 2.77e^0.048Q
Ref EU (old)
21
62
N/mm2
150 mm cube
fck = 1.8943e^0.064Q
Ref CN
20
75
N/mm2
150 mm cube
fck = 0.0244Q^2-0.6129Q+10
Ref RUS
20
77
N/mm2
150 mm cube
fck = 0.03Q^2-0.86Q+9.5
Mean strength
10
75
N/mm2
150 mm cube
fck = 3.6473e^0.0475Q
Characteristic strength Q
10
95
N/mm2
150 mm cube
Step function (see below)
No angle correction is required for measurements with the Silver Schmidt.
Note! The Ref EU curve was determined with very high quality concrete and gives very high strengths.
The characteristic strength curve is based on the reference table for the screening test provided in the Annex to EN13791. This curve provides a safe estimate with <5% probability of over-estimating the strength.
Q value - Strength (N/mm2) 10 to 33 - <10 34 to 39 - 10 40 to 44 - 15 45 to 48 - 20 49 to 51 - 25 52 to 55 - 30 56 to 59 - 37 60 to 61 - 45 62 to 63 - 50 64 to 65 - 55 66 to 67 - 60 68 to 70 - 67 71 to 72 - 75 73 to 74 - 85 75 to 80 - 95
How should I apply impact angle correction to my rebound hammer test result?
Here it is necessary to differentiate between classical rebound hammers (R-value) and the Silver Schmidt hammers (Q-value). Classical rebound hammers require an impact angle correction when the impact is not carried out...
Here it is necessary to differentiate between classical rebound hammers (R-value) and the Silver Schmidt hammers (Q-value). Classical rebound hammers require an impact angle correction when the impact is not carried out horizontally. For the Original Schmidt, the correction can be found in the manual for vertically up and vertically down measurements. The Original Schmidt OS8000 applies a more advanced impact angle correction automatically for any angle. On the app, the user can see both the uncorrected and the corrected values. The Silver Schmidt hammers are intrinsically impact angle independent so no correction is necessary.
Which conversion curve should I use with my rebound hammer?
There is no simple answer to this question.
The answer depends on the region you are in and the standards you are working to. In China for example there are standardized correlation curves, which may be selected in the...
There is no simple answer to this question.
The answer depends on the region you are in and the standards you are working to. In China for example there are standardized correlation curves, which may be selected in the Original Schmidt Live app. Other regions such as Korea and Japan have nationally accepted correlation curves that are widely used. These may also be programmed directly into the Schmidt Live app and used. However, unless the standard you are using provides a method to use standardized curves then you should always calibrate your hammer to the concrete under test using a custom materials curve. If this is not possible we recommend using the lower 10th percentile curve with the Silver Schmidt OS8200 hammer to give a conservative estimate. This is a safer option with a smaller chance of overestimating the strength. Another option is to use the EN13791 screening test with either Original Schmidt OS8000 or Silver Schmidt OS8200 which again gives a conservative estimate. The use of custom material curves is fully explained in the tutorial "12. Custom materials" included in the Original Schmidt Live app.
How do I create a custom materials curve for my rebound hammer?
In order to create a custom materials curve, it is necessary to record rebound values at a number of locations in the structure where cores will be taken. Alternatively, rebound measurements can be made on standard cubes...
In order to create a custom materials curve, it is necessary to record rebound values at a number of locations in the structure where cores will be taken. Alternatively, rebound measurements can be made on standard cubes or cylinders which are then crushed in the press to determine the actual compressive strength. This data is then used to create a custom material curve using a simple spreadsheet function. The complete procedure is explained in the tutorial video "12. Custom materials" included in the Original Schmidt Live app.
Is it possible to use the mushroom plunger with the Original Schmidt OS8000?
No, it is not possible. The mushroom plunger was specifically designed or use with the Silver Schmidt OS8200 type L. It extends the range of the hammer down to approximately 5 MPa and is typically used for the...
No, it is not possible. The mushroom plunger was specifically designed or use with the Silver Schmidt OS8200 type L. It extends the range of the hammer down to approximately 5 MPa and is typically used for the determination of the early strength of concrete. e.g. for formwork removal in tunnel applications.
ГОСТ 22690
ACI 228.1R