Which permeameter should you choose for your geotechnical laboratory? (CT0245 vs CT0246 vs CT0248)

In a civil engineering or geotechnical laboratory, determining the permeability coefficient (k) of soils is a fundamental test. Whether it is to verify the watertightness of a formwork base, check the drainage of a sub-base layer or study the behaviour of a clayey soil, choosing the right equipment is crucial.

At CTRMAT, our equipment meets all regulatory requirements (NF EN ISO 17892-11, ASTM D2434, BS 1377). However, given the wide variety of products available, it can sometimes be difficult to make the right choice.

Here is a detailed comparison of our three flagship configurations: the CT0245, the CT0246 and the CT0248.

1. Model CT0245: The specialist in granular soils with constant load

The CT0245 is the benchmark system for measuring the permeability of highly drainable materials such as sand, gravel and aggregates.

• Test principle: Constant head test (Constant Head). The test specimen is continuously supplied with water to a fixed height by means of a constant-level tank fitted with an overflow.
• Design: Transparent reinforced plexiglass chamber (available in Ø 75 mm or Ø 114 mm) framed by anodised aluminium flanges.
• Key strengths:​
  • A transparent body that allows visual observation of soil saturation and water flow.
  • Direct reading of the water flow rate through the sample.

Ideal for: Testing materials with high permeability (k > 10⁻⁵ m/s) where the water flow rate is sufficient to be measured over a given time interval.

2. Model CT0246: Precision for fine soils with variable loads

The CT0246 is designed specifically for the analysis of low-permeability soils such as clays, silts or compacted fine-grained soils.

• Test principle: Variable-load test (Falling Head). A precision manometric tube is filled, and the time taken for the water level to fall from a height H1 to a height H2 as it passes through the soil is measured.
• Design: A robust wall-mounted panel fitted with three glass manometric tubes of different internal diameters (3, 4 and 6 mm), combined with a sealed metal compaction mould (Ø 4‘ or Ø 6’).
• Key strengths:
  • Extremely high measurement accuracy, suitable for low flow rates.
  • Flexibility provided by the three tubes of different sizes, allowing the rate of fall to be adjusted in line with the low permeability of the soil.
  • The soil can be compacted directly in the test mould.

Ideal for: Clay and loam soils with very low permeability (k < 10⁻⁵ m/s).

3. Model CT0248: The complete multi-station workstation for high-speed production

The CT0248 is our top-of-the-range solution designed for high-volume testing laboratories requiring high throughput.

• Test principle: This versatile system allows tests to be carried out at constant load OR variable load.
• Design: Free-standing metal frame (height adjustable from 1.35 m to 3.45 m) incorporating an overhead water tank and up to 4 independent measuring columns.
• Key strengths:​
  • Productivity increased fourfold: Allows up to four compaction moulds (Ø 4‘ or Ø 6’) to be tested in parallel.
  • Centralised management of fluids and pressure gauges on a single, ergonomic workstation.

Ideal for: Construction testing laboratories and research centres that need to process large numbers of sample sets simultaneously.

Need some technical advice or a bespoke quote?

Our technical teams are on hand to advise you on the most suitable equipment for your site or laboratory requirements.

📞 Telephone : +33 (0)1 85 13 27 02

✉️ Email : contact@ctrmat.fr