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Showing posts from April, 2017

Steps to Follow While Using a Schmidt Hammer

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The Schmidt Hammer is a valuable instrument for testing concrete. Inside the hammer is a sensor that measures the rebound value of the test impact with repeatability and high resolution. The hammer is also known as a ‘rebound hammer’, with ‘rebound’ pertaining to the effective, non-destructive way to measure the compressive strength of concrete to within a 20 percent range, and the control of uniform concrete quality in prefabricated structures and in-situ concrete. Certain steps must be followed to ensure accuracy and proper use of the Schmidt Hammer . Here are some of the guidelines to consider: Refer to ASTM C805-13 – The standard test method with a Schmidt hammer is listed under ASTM. The latest standard provides the procedures for the test method for rebound number of hardened concrete.   Calibrate the hammer – A good supplier offers equipment with calibration certificates and recalibration services.   Make sure the concrete is ready f

Measuring Metallic Corrosion with Half Cell Potential Test

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When reinforcing steel corrodes inside concrete, an electro-chemical process occurs and its characteristics can be identified with a half-cell potential (HCP) measurement, also known as a ‘half cell potential test’. HCP measures metallic corrosion to determine the regions of potential corrosion and the risk it can impose on the structure. Date interpretation is nuanced and specific to particular sites, but generally a more negative potential means a risk of corrosion occurring in unsaturated marine exposed concrete. To conduct the test, an electrode is used to form one part of the bimetal cell, while the reinforcing steel within the concrete serves as the other half. Silver/silver chloride in a potassium chloride solution or a simple Copper/Copper Sulphate cell is the ideal reference electrode for use on-site. An electrode that is made of copper/copper sulphate is widely used, too. An advanced half cell potential meter is a great instrument to have for a more reliable way to

Useful Applications of Ground Penetrating Radar

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Ground penetrating radar (GPR) is state-of-the-art equipment used for exploring the subsurface of the earth. The cutting-edge imaging technology found in high-end GPR systems measures electromagnetic wave propagation and echo from the subsurface, which images and identifies changes in the magnetic and electrical properties beneath the surface of the earth. Hence, GPR systems are useful in locating underground utility lines in earth or post tensioning and reinforcing in concrete. Ground penetrating radar is surprisingly versatile for many other applications, including forensic research, land surveying, detecting unexploded land mines, conducting groundwater studies, and monitoring the structural integrity of airplane runways. GPR is useful in many different fields. It is used to study ice, groundwater, soil, and bedrock under earth sciences and it may be helpful in finding diamonds and gold nuggets in alluvial gravel beds. In that case, ground penetrating radar is used to fi

Precautions to Be Taken While Using a Piezometer

The piezometer is a measuring device that determines pore pressures underground and liquid pressure. By determining pore pressure, you can understand the behaviour of the ground before, during, and after a construction project. Certain precautions must be taken when using a piezometer to ensure proper usage and the accuracy of results. Here are some of them: Have the right equipment – Invest in a state-of-the-art piezometer that uses a proven method of converting fluid pressures on the sensitive diaphragm into frequency signals which are ideal in the demanding environment common with civil engineering applications. Modern piezometers are capable of long distance signal transmission without degradation. They can tolerate wet wiring conditions and resist external electrical noise, too. Some manufacturers make piezometers specific for different applications, for instance, you should be able to find one with a heavy-duty body that can be b

Know About Concrete Strength Test and Its Application

Hardened concrete can be tested to determine its strength and quality. Concrete strength tests are designed to determine the compressive strength of the material and its ability to resist loads. Here are some of the things you should know about it: Why it’s done – Compressive strength tests are conducted to ensure that the concrete mixture being used for construction can meet the requirements for specified strength in a given job specification. How it’s done – Concrete cylinders must be created and cured following the procedures described in the AS1012.8 for cured specimens before they are tested.  That way, you can be sure that you can conduct the concrete strength test correctly and the results will be reliable.. Cylindrical specimens are tested following AS1012.9, under the test method for compressive strength of cylindrical concrete specimens. The formula - Concrete’s compressive strength is measured by div