Proper repair concrete methodology should begin with testing, to identify the type and extent of defects and the overall quality of the concrete or steel structure. Gemite provides Non-Destructive testing, which delivers an analysis of the existing conditions, and helps to determine the most appropriate repair method and materials to be used.The Non-Destructive equipment and techniques used by Gemite provide instant and precise information regarding the concrete electrical resistance, probability and rate of rebar corrosion, location of hidden flaws, placement of reinforcement, reinforcement cover, concrete compressive strength and structural rigidity. The diagnosis also includes determination of chloride ion content, its distribution and carbonation depth.
As part of our service, Gemite also provides consulting services for the co-ordination and analysis of laboratory testing such as compressive strength, petrography examination, and alkali aggregate reactivity (AAR). Some of the methods used by Gemite are:
Ground penetration radar scanning and 3D imaging
Radar uses electromagnetic pulses, to penetrate concrete up to 1 m and produces high-resolution images from the reflected waves of embedded volumes, which exhibit different dielectric characteristics. The method is used mainly in determining internal defects, voids, positioning of reinforcing steel and other objects embedded in the concrete.
Impact-Echo is a powerful tool, similar to radar technology, for finding any variations of sonic impedance within concrete. Impact-echo technique is sensitive to dry voids and cracks, as well as the presence of steel and other objects embedded in concrete.
Water Permeability Tests
The concrete permeability is the most important parameter controlling the long-term durability of concrete. The water permeability testing uses equipment in conformance with EN-ISO 7031, to determine the water permeability coefficient.
The corrosion rate of a steel rebar is measured using the polarization method, with the rebar acting as a working electrode and Ag/AgCl as the reference electrode. Galva-Pulse equipment polarizes the steel rebar under an established drop of potential and computes the corrosion loss of mass, using Faraday’s Law. In addition, half-cell potentials and the electrical resistance of the concrete cover layer are also measured.