Original Schmidt Hammer: Concrete Test Hammer, Type N
The Original Schmidt Concrete Test Hammer is the classic analog rebound hammer for accuracy, reproducibility and reliability. When you hit the surface the piston is automatically released onto the plunger, so you get accurate measurements. It’s a fast, non-destructive method for compressive strength of hardened concrete, concrete uniformity and rock hardness, but the readings can be affected by the orientation of the hammer during the test.
Digital systems like the Schmidt Live have automatic calculations for various test parameters including impact angle correction to improve non-destructive testing methods.
The Type N test hammer is the most popular and cost effective way to test concrete strength, integrity and uniformity. Designed for testing concrete 4inches (100 mm) or more in depth, it’s a must have tool for professionals in the construction and civil engineering industry in the USA and beyond. For concrete with cross-section less than 4 inches (100 mm) see the HM-75L Original Schmidt Hammer, Type L, with 0.735 Nm (0.54 ft-lb) impact energy for better reproducibility.
Specs:
-
Overall length: 11.1 inches
-
Width: 2.2 inches
-
Height: 2.2 inches
-
Weight: 3.3 lbs
-
Impact energy: 2.207 Nm (1.63 ft-lb)
-
Compressive strength range: 1450 - 10,152 psi (10 - 70 MPa)
Features:
-
Time-tested, Swiss-made design
-
Works on concrete with compressive strengths from 1,450 to 10,152 psi (10 to 70 MPa)
Includes:
-
Original Schmidt Concrete Hammer (Type N)
-
Plastic carrying case
-
Carborundum stone for preparation
-
Reference chart
-
Certificate of conformity
These concrete testing hammers come with everything you need to calibrate them using a specific calibration test anvil provided by the manufacturer. The plastic carrying case protects the hammer and its accessories during transport, perfect for field use. The carborundum stone prepares the concrete surface for accurate and consistent test results. For those working with asphalt surfaces, Certified Material Testing Products offers a variety of asphalt tools to ensure professional results.
Our Schmidt Type N Concrete Hammers meet:
-
ASTM C 805
-
BS 1881-202
See the full range of Schmidt Concrete Test Hammers and Non-Destructive (NDT) concrete equipment and boost your testing capabilities with our wide range of tools and accessories for accuracy and durability.
Overview
Schmidt hammers also known as rebound hammers or concrete hammers are essential tools to estimate the mechanical properties of concrete and rock materials. Getting multiple measurements is key to ensure accuracy when testing surface strength. These non-destructive devices measure surface hardness and penetration resistance by bouncing a spring-loaded mass against the material’s surface. The rebound value obtained from this process is then used to calculate the compressive strength of the material, with mean R values calculated from multiple measurements. We offer several models, including the Original Schmidt Hammer, Silver Schmidt, and Schmidt Live, each designed with varying impact energy and features to meet your specific needs.
What is Concrete Testing?
Concrete testing is a critical process in the construction industry, to ensure concrete structures meet the required standards of strength, durability and safety. One of the most popular tools for testing concrete is the Schmidt hammer, also known as a rebound hammer or concrete hammer test. The Schmidt hammer measures the surface hardness of concrete by rebounding a spring-loaded mass against the surface, giving an indication of the concrete’s compressive strength. This non-destructive testing method is essential for evaluating the condition of existing concrete structures and ensuring the quality of new constructions. By using the Schmidt hammer, professionals can quickly and accurately assess the integrity and durability of concrete, making it a must have tool in the construction industry.
History of Schmidt Hammers
The Schmidt hammer was invented by Ernst Heinrich Wilhelm Schmidt, a Swiss engineer, in the 1950s. The original Schmidt hammer was introduced into the market by Proceq and has since become the world’s most widely used instrument for non-destructive estimation of concrete strength properties. Over the years the design and technology of Schmidt hammers have evolved, new models have been developed to improve accuracy, precision and user experience. Today there are several types of Schmidt hammers available, including the Original Schmidt, Silver Schmidt and Schmidt Live, each with its own features and applications. These advancements have made Schmidt hammers more versatile and reliable, making them a must have tool in the construction and civil engineering industry.
Principle of Operation
The principle of operation of a Schmidt hammer is based on the measurement of the rebound from a controlled impact on an area. The device has a spring-loaded piston that when pressed perpendicularly against a surface releases onto a plunger. During this impact some of the energy is absorbed and transformed, the rest is the impact penetration resistance of the surface. The energy from the impact, which is not absorbed or transformed into heat and sound, represents the hard or impact resistance of the surface. The harder the surface the higher the rebound value. The Schmidt hammer measures this rebound value on an arbitrary scale from 10 to 100, where the remaining energy represents the surface hardness and compressive strength.
Types and Applications
Schmidt hammers have many applications:
-
Structures: Used to estimate the strength of structures such as buildings, bridges and roads, Schmidt hammers provide a quick and non-destructive way to test structural integrity.
-
Rock Material Characterization: In geology and construction hammers are used to estimate the mechanical properties of rock materials and penetration resistance. Correlation curves are used to analyze and predict the mechanical properties of rock materials, reflecting microstructural changes and the relationship between different rebound values.
-
Geomorphological Research: In geomorphological studies hammers are used to test the strength of bedrock and boulder surfaces to understand landscape formation and erosion processes. The Type N Schmidt hammer is most frequently used in geomorphological research to test rock hardness through non-destructive methods.
-
Paper and Mortar Testing: In addition to rock, hammers are also employed to assess the hardness of paper and mortar materials, showing their versatility. Variations in weathering degrees can significantly affect test results and correlations in rock mechanics.
Maintenance
To ensure the accuracy and durability of hammers maintenance and repair is key. Here are some tips:
-
Calibration: Calibration with a calibrated test anvil supplied by the manufacturer is mandatory to keep the hammer accurate.
-
Cleaning: Regular cleaning prevents dirt and debris to affect the hammer’s performance and results.
-
Storage: Store in a dry and safe place to prevent damage and extend the life of the hammer.
-
Repair: Repair by a qualified technician if damaged to keep the hammer
It is important to show the mean value and the 95% confidence interval for each site sampled to have clarity in data reporting.
By following these maintenance and repair guidelines users can ensure their Schmidt hammers will give precise and reliable results for years to come.
