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Electronic device diagnoses corrosion in concrete structures
international
news
features a cartridge-type seal assembly which allows dynamic seals to be replaced in minutes. Since the size of the lance is changed to suit the materials being handled, the machine has its own hydraulics to disengage the lance from its seals without physical effort The machine, the first of which has been installed in Bradford University, is suitable for use with a range of commercially available injection heads and with its option of closed loop computer control on all lances and injection head plungers, it is possible to carry out research involving special IPN (interpenetrating network) heads, where sequencing of injection streams and effects may be studied. *RIM is the process whereby reagents (chemicals) in the liquid state are simultaneously mixed and injected into a mould where they react and form a solick Reinforced RIM
involves the addition of reinforcing materials- typically glass fibres, carbon fibres - to the reagent to enhance the mechanical properties of the resultant polymer and finished product. The current interest in RRIM stems mostly from its applications in the automotive industry, which sought to replace steel body parts with lower weight, less corrosionprone, impact-resistant panels. RIM and RRIM have the advantages of relatively low cost equipment, low energy requirements and the choice of a wide range of properties when using existing polyurethane formulations.
Electronic device diagnoses corrosion in concrete structures
The operator, by taking readings at regular intervals (equal to the spacing of the half-cells), can build up a grid pattern of the corrosion potentials and the logger will analyse these and re-print them as a corrosion potential map. The resulting map will indicate the regions of the structure where rebars are corroding. It will also give some idea of the source of the problem, since the map allows the corrosion to be traced back to and associated with surface damage, spalling or variations in the concrete composition. Colebrand: 20 Warwick Street, Regent Street, London W l R 6 B E . Tel: 01-439 9191
The condition of reinforcing bars in concrete structures has to be regularly checked for deterioration, but, ideally, an effective non-destructive testing procedure is required. Scientists have been using the N D T technique of half-cell measurements for a number of years, but the time-consuming nature of the technique prompted the Transport and Road Research Laboratory to develop a microprocessor-based version, now produced under licenee. The equipment consists of two parts. An array of half-cells and a data logger complete with a miniature printer. In operation, the array of half-cells is pushed forward by the operator, while the electronics are carried over the shoulder. When measurements are taken, the array of half-cells is pressed into the concrete surface by tilting the bar into the contact position. The voltage readings between the reinforcing bar in the concrete and the eight half-cells of the test equipment are taken via a high impedance buffer to a temporary data store. After each scan of the array, the numerical values of the potentials are printed out on the miniature printer.
Oil changes eliminated by purifier/conditioner The Pura-Trol purifier/conditioner is designed for all petrol and diesel powered engines that use oil for lubrication, coolin~ cutting or hydraulics. Filtration is accomplished by
4
Holden Hydromar~ Station Industrial Estate, Bromyard, Herts HR7 4HP
the basic physical principles of particle collision, pressure, gravity and sedimentation. These processes all take place within a multi-chamber arrangement constructed from the stem and plates, which are permanently sealed inside the base and housing assembly. Oil enters the upper chamber at high speed, throwing particles against a knurled inside wall. The particles are then forced downward into a second chamber where the oil continues to rotate, but at a lower speed. By the time the oil is forced through a perforated disc into a third chamber it is almost at a standstill. Finally, it is forced through another, precision-perforated disc, into a sedimentation chamber,
MATERIALS & DESIGN Vol. 6 No. 1 FEBRUARY/MARCH 1985
news
features a cartridge-type seal assembly which allows dynamic seals to be replaced in minutes. Since the size of the lance is changed to suit the materials being handled, the machine has its own hydraulics to disengage the lance from its seals without physical effort The machine, the first of which has been installed in Bradford University, is suitable for use with a range of commercially available injection heads and with its option of closed loop computer control on all lances and injection head plungers, it is possible to carry out research involving special IPN (interpenetrating network) heads, where sequencing of injection streams and effects may be studied. *RIM is the process whereby reagents (chemicals) in the liquid state are simultaneously mixed and injected into a mould where they react and form a solick Reinforced RIM
involves the addition of reinforcing materials- typically glass fibres, carbon fibres - to the reagent to enhance the mechanical properties of the resultant polymer and finished product. The current interest in RRIM stems mostly from its applications in the automotive industry, which sought to replace steel body parts with lower weight, less corrosionprone, impact-resistant panels. RIM and RRIM have the advantages of relatively low cost equipment, low energy requirements and the choice of a wide range of properties when using existing polyurethane formulations.
Electronic device diagnoses corrosion in concrete structures
The operator, by taking readings at regular intervals (equal to the spacing of the half-cells), can build up a grid pattern of the corrosion potentials and the logger will analyse these and re-print them as a corrosion potential map. The resulting map will indicate the regions of the structure where rebars are corroding. It will also give some idea of the source of the problem, since the map allows the corrosion to be traced back to and associated with surface damage, spalling or variations in the concrete composition. Colebrand: 20 Warwick Street, Regent Street, London W l R 6 B E . Tel: 01-439 9191
The condition of reinforcing bars in concrete structures has to be regularly checked for deterioration, but, ideally, an effective non-destructive testing procedure is required. Scientists have been using the N D T technique of half-cell measurements for a number of years, but the time-consuming nature of the technique prompted the Transport and Road Research Laboratory to develop a microprocessor-based version, now produced under licenee. The equipment consists of two parts. An array of half-cells and a data logger complete with a miniature printer. In operation, the array of half-cells is pushed forward by the operator, while the electronics are carried over the shoulder. When measurements are taken, the array of half-cells is pressed into the concrete surface by tilting the bar into the contact position. The voltage readings between the reinforcing bar in the concrete and the eight half-cells of the test equipment are taken via a high impedance buffer to a temporary data store. After each scan of the array, the numerical values of the potentials are printed out on the miniature printer.
Oil changes eliminated by purifier/conditioner The Pura-Trol purifier/conditioner is designed for all petrol and diesel powered engines that use oil for lubrication, coolin~ cutting or hydraulics. Filtration is accomplished by
4
Holden Hydromar~ Station Industrial Estate, Bromyard, Herts HR7 4HP
the basic physical principles of particle collision, pressure, gravity and sedimentation. These processes all take place within a multi-chamber arrangement constructed from the stem and plates, which are permanently sealed inside the base and housing assembly. Oil enters the upper chamber at high speed, throwing particles against a knurled inside wall. The particles are then forced downward into a second chamber where the oil continues to rotate, but at a lower speed. By the time the oil is forced through a perforated disc into a third chamber it is almost at a standstill. Finally, it is forced through another, precision-perforated disc, into a sedimentation chamber,
MATERIALS & DESIGN Vol. 6 No. 1 FEBRUARY/MARCH 1985