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Germann Instruments - Model COMA-Meter -COncrete MAturity-Meter

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The COMA-Meter is a state-of-the-art maturity reader designed for newly cast concrete, providing key metrics for engineers and construction professionals. Utilizing a glass capillary tube containing a specially formulated liquid, the device measures the evaporation rate, which varies according to the temperature, to determine the concrete’s maturity. Embedded at a depth of 80 mm into the concrete, it operates based on the Arrhenius equation for temperature-dependent rate processes. The maturity level, expressed in M20 units, equates to days of curing at 20 ºC, allowing precise monitoring of early-age compressive strength and effective in-place curing temperature. With models reading up to 5 or 14 M20 days, this tool is crucial for managing concrete curing and timing pullout tests like LOK-TEST.

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The COMA-Meter (COncrete MAturity-Meter) is used to measure the maturity of newly cast concrete at a depth of 80 mm from the surface.
A glass capillary tube contains a special liquid for which the rate of evaporation varies with temperature according to the Arrhenius equation that is used to determine maturity of concrete from its temperature history. After the concrete is cast, the COMA-Meter is pushed into into the fresh concrete and the liquid in the capillary tube will evaporate at a rate determined by the temperature and time. The level of the liquid, readable on the scale, measures the maturity of the concrete stated in M20 units, which is the number of equivalent days of curing at 20 ºC.

• Estimating the compressive strength at an early age using a pre-established strength-maturity relationship
• Timing of pullout testing with LOK-TEST (consult Technical Data Sheet) for early-age strength measurement
• Evaluating the effective in-place curing temperature.

  • Measuring ranges:
    • COMA-5 = 0 to 5 M20 days
    • COMA-14 = 0 to 14 M20 days
  • Precision: ±0.1 M20 days
  • Accuracy: ±5 % compared with maturity values calculated from direct temperature readings
  • Activation energy, E ≈ 40 kJ/mol.