Silver Schmidt Hammer

TRADITIONAL HAMMERS VS SILVERSCHMIDT

The classical hammers suffer from the following insufficiencies:

The rebound value is dependent on the impact direction.
The rebound value is affected by internal friction.
Limited tightness of sealing causes premature loss of accuracy.

The unique design and high quality construction of the SilverSchmidt address all of these issues and makes rebound hammer testing quicker and more accurate than ever before. Conversion curves are provided for a wide range of compressive concrete strength, including low and high strength concrete fc <10 MPa (5MPa using Mushroom Head) and up to 100MPa. Conversion curves for different types of modern concrete are preset in the Silver Schmidt, based on tests performed by an independent institution

DEPENDABLE MEASURING RESULTS

High accuracy due to differential optical absolute velocity encoder
Measurement inherently independent of impact direction, meaning no corrections necessary
Built-in correction for carbonation and form factor gives increased test accuracy and dependability of test results
Registration of true rebound coefficient yields extended resolution across a wider range
Silver Schmidt can also display the classic R value

CONTROLLED AND EXTENDED FUNCTIONALITY

Automatic control of functionality by monitoring impact energy
Low power consumption, high capacity lithium-ion battery
The Mushroom Head attachment has a larger surface area and is used for early age strength or softer materials

APPLICATIONS

Suitable for testing a wide variety of concrete, mortar, rock, paper and plastics
Ideally suited for on-site testing
Handy for difficult to access or confined test areas (i.e. working overhead)
Especially convenient for testing on tunnel linings as measurements are independent of impact direction

OPERATION

Simple operation with the "one button" user interface
Language independent through the use of graphic user interface
Automatic conversion to the required measurement unit (MPa, kg/cm2, psi),
Various statistics to comply with standards or user specified procedures
Custom presets of test parameters for various testing scenarios can be stored and later recalled
Quick review of previous measurements

To obtain a reading in units of compressive strength select:

Desired unit
Length of series and averaging mode
Carbonation depth (if applicable)
Conversion curve for concrete mixture
Form factor

Perform a test series of specified length. Manual cancellation of obvious outliers is possible. At the end of the series, the instrument will display the average converted to the desired unit.

MEASURING TRUE REBOUND COEFFICIENT ("Q"-VALUE)

The classic "R"-value is the mechanical travel of the mallet on rebound. It is affected by its friction on the guide rod, the friction of the gauge, gravity, the relative velocity between unit and mechanical parts. This is true for all concrete test hammers currently on the market.
The Silver Schmidt acquires the "Q"-value by measuring the velocity (V) of impact and of rebound immediately before and after the impact. The "Q"-value need not be corrected for impact direction. There is a clear relationship between the "Q" and the "R"-value.
The "Q"-value [=rebound V divided by inbound V] represents the physical rebound coefficient. It is virtually free of all the above error sources. It is thus the indicator of choice to be used as a basis to convert to compressive strength.

NEW IMPROVED PLUNGER

The lightweight hybrid design of the impact plunger is made from aerospace alloy, matched to the elastic properties of the concrete and equipped with a hardened steel cap. Independent validation testing by BAM in Berlin has shown the SilverSchmidt to have less dispersion than the classical hammer over the entire range.

HAMMERLINK

The ST Model Silver Schmidt only has the capacity to display the last 20 results. The PC Model Silver Schmidt on the other hand is the extended data logging model, it can log 1300 single impacts or over 465 measurement series, each with 10 readings. The data is then downloaded to PC using the Hammerlink application and a USB cable.

Extended memory usage
Rapid uniformity assessment with the summary view
Sorting of data
User-defined conversion curves
User-defined statistical methods
Highlighting of mean, median and outliers
Carbonation correction
Export to third party software

10th PERCENTILE CONVERSION CURVE

A lower 10th percentile curve is recommended by the major standards EN 13791 and ASTM C805/ACI 228.1 to provide a safety margin to take into account the various factors that may affect the in-situ tests. 90% of the data pairs lie above the curve and 10% lie below. This curve is intended to give a conservative estimate in those cases that the hammer is not calibrated for the specific mix under test. For older hammers firmware release v1.0.3 adds the new curve to your hammer.

ROCK TESTING

Schmidt hammers are used internationally for testing of rocks as well as concrete/cementitious material. ASTM D5873 (Rock) has been developed as a stanadrd for this form of testing. Generally an L Type Hammers is used. Conversion to UCS also rely on the mineralogy of the rock in question. Many conversion curves exist, but none are included on the Silver Schmidt. Schmidt Hammers lend themselves to grading rock core in the lab and testing rocks in the field.

COMPLIANCE WITH INDUSTRY STANDARDS

Data collection and processing of test results comply with major industry standards: EN 12504-2, ENV 206 ASTM C805, ASTM D5873 (Rock), BS 1881, part 202

SPECIFICATIONS

Test Hammer	Type N	Type L
Impact Energy	2.207 Nm	0.735 Nm
Compressive Strength Range	10 - 100 MPa	10 - 100MPa (5 - 100 MPa with Mushroom Head)
Weight	600g
Battery Life	>4000 impacts (before recharging)

Additional Information

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