Geneq > Materials testing > Hammers

The Original SCHMIDT fully integrated electronic concrete test hammer
Extended Range of Applications
Conversion curves are provided for a wide range of compressive concrete strength, including low and high strength concrete fc <10 N/mm2 (1.450 psi) and up to 170 N/mm2 (24.650 psi) Conversion curves for different types of modern concrete are preset in the SilverSchmidt, based on tests performed by an independent institution
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 JGJ/T 23-2001 (China)
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 dependendability of test results Registration of true rebound coefficient yields extended resolution across a wider range SilverSchmidt 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 Tightly sealed instrument providing a higher number of impacts without servicing
On concrete walls, decks and pillars...at any angle
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
Primary Customers
Contractors Engineers, consultants Quality control, site supervision Universities, education and research establishments Laboratories Geologists
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 (N/mm2, 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
Performing the Impact Test
1. Place the unit perpendicular to the test surface	2. Load the unit by pushing it towards the test surface	3. Impact is triggered when the end position is reached
Determine the Compressive Strength
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.
Typical Display Window
Single Impact A typical display after an impact shows: • The actual "Q"-value • A pseudo-analog scale • A counter with double function either displays the last two digits of the 4-digit-totalizer or the actual number of valid impacts in a test series
Measuring Series
Median/Mean after a test series; compressive strength displayed in N/mm2, psi, kg/cm2
Measuring the 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 drag pointer on the scale, the influence of gravity during its travel, the relative velocity between unit and mechanical parts. This is true for all concrete test hammers currently on the market. The "Q"-value [=rebound velocity divided by inbound velocity] 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. The SilverSchmidt acquires the "Q"-value by measuring the velocity of impact and of rebound immediately before and after the impact. The "Q"-value need not be corrected for impact direction. There is however a clear relationship between the "Q" and the "R"-value.
Technical Information
Mechanical data	BN–type	BL-type
Impact energy	2.207 Nm	0.735 Nm
Hammer mass	115 g	115 g
Spring constant	0.79 N/mm	0.26 N/mm
Spring extension	75 mm	75 mm
Housing dimensions	55 x 55 x 250 mm (340 mm to tip of plunger)
Dimensions (visible part of plunger)	105 x ø15 mm / radius of spherical tip 25 mm
Weight	600 g
Electrical data
Display	17 x 71 pixels; graphic / alphanumeric
Power consumption	~13mA measuring, ~4 mA setup and review, ~0.02 mA idle
Accumulator duty	> 1'000 chocs (before recharging)
Charger connection	USB, type B (5 V, 100 mA)
Useful ranges
Concrete compressive strength	10 N/mm2 to 170 N/mm2 (1.450 psi à 24.650 psi)
Operating temperature	0 to 50 °C
Storage temperature	-10 to 70 °C