Non Destructive Testing
Non Destructive Testing
Our inspections, checks and surveys are based on non-destructive tests that do not alter any structure or material of the building and also do not require any removal of test samples from its structure.
We employ a variety of tests to evaluate the concerned parts of a building without interfering with the structure in any form.
ULTRASONIC PULSE VELOCITY (UPV) TEST
The UPV method works by initiating a pulse on the boundary of a material and measuring the time taken for the pulse to travel to an apposite boundary or be reflected back to the first boundary. Employed in situ, the UPV method is widely used to measure concrete uniformity/continuity in the stone masonry / effectiveness of lime mortar, in detecting cracks and honeycombs, estimating the strength and concrete deterioration, measuring elastic modulus, and monitoring strength development.
REBOUND HAMMER TEST
We use the Rebound Hammer Test to measure the compressive strength of concrete, or in simpler terms, the surface hardness of concrete. A Schmidt Hammer is pressed against the surface of concrete to be tested, and the extent of the print-controlled mass rebound is recorded as a measure of the concrete’s surface hardness.
The underlying principle of the test is that surface hardness and the rebound generated are related to compressive strength of the concrete. Rebound value is read from a graduated scale as the Rebound Index, which is calibrated by the manufacturer to indicate the compressive strength, made visible on the body of the hammer.
CARBONATION TEST
This test measures the pH of concrete. A freshly placed concrete has an alkaline pH of 12 to 13, which protects the underlying steel from corrosion, even under high moisture conditions. However, at pH levels of 11.5, even normal levels of moisture cannot prevent corrosion of concrete, which occurs in the form of carbonation. If the depth of cover for concrete is low, the carbonation can soon reach the steel underneath. Further, corrosive products occupy more volume as compared to the original metal; tensile stresses ensue, leading to cracking of the concrete. Testing of concrete for carbonation using a chemical indicator can help determine the presence and extent of corrosion undergone by it.
The test is conducted on a freshly broken face of concrete, which is first washed with distilled water to remove dust and any other contaminant present on the surface that may interfere with test results. An indicator solution is sprayed on the surface and color changes are recorded.
POTENTIAL METER TEST
Simple, economical and virtually non-destructible, the Half-cell Potential Meter Test assesses the corrosion risk to steel in a concrete structure. Reinforced steel that is protected by a passive film of high-alkalinity pore water is susceptible to exposure through carbonation of concrete or penetration of Chloride ions (from the sea or rock salt)
An indicator of steel corrosion is the development of macrocells or Galvanic corrosion cells, a combination of protected and corroding areas of the reinforcement bar. A flow of current through the steel bar generates an electric field that is measured at the concrete surface, indicating the highest corroded areas.
We conduct this test on concrete columns, beams and slabs by making an electrical connection to an exposed steel reinforcement in concrete and measuring its half-cell potential with respect to a number of reference electrodes that are inserted in the galvanic corrosion circuit. The greater the negative value of potential readings, more active is the corrosion process.
Concrete Core Test
Cores are generally taken out from the Concrete Slabs , Beams, columns of old structures. The cores are taken at the selected points generally avoiding the positions of the reinforcement.
