Sulphate acidic soils: Preventing corrosion in buildings through soil analysis

For construction projects on sulphate acid soils, WESSLING supports the risk assessment in advance through soil analysis. This enables you to take measures in good time to prevent corrosion on building components and thereby avoid delays in the construction process.

swamp soil

Sulphate acidic soils occur near seacoasts, in marshlands, moors and mudflats, among other places. Due to the constantly high groundwater levels in these areas, reduced inorganic sulphur compounds, for example iron sulphides such as pyrite or marcasite, are preserved in the soils. These can attack structural elements such as concrete pillars and thus lead to instability of the building. This is why it is so important to be aware of risks, in advance, when preparing a construction project. With comprehensive soil analysis, WESSLING provides the basis for action in order to excavate the soil to required levels, prepare it and, if necessary, change the building materials. Our experts provide support with analyses in compliance with BBodSchV (German Soil Protection Ordinance) for the further disposal or recycling of the soil.

WESSLING is one of the few laboratories that can determine the acidification potential due to reduced inorganic sulphur compounds in the soil according to the Geofacts 25 recommendation.

Moreover, the need for extensive excavation of sulphate acid soils poses significant risks to the environment. PASS soils (potential acid sulphate soils) do not pose a risk when they are in an undisturbed state. However, when the soil is excavated, aeration causes acid and sulphate to form; and oxidation and acidification usually occur very quickly. If the soil is then not sufficiently secured or properly disposed of, this can both inhibit plant growth in the surrounding area and contaminate the groundwater.

Hazard potential of sulphate acid soils*:

  • Extreme acidification (pH <4.0), which causes plant damage or prevents plant growth
  • Increased availability or solubility of aluminium and heavy metals and increased metal concentrations in leachate (test, measure or precautionary values according to BBodSchV may be exceeded)
  • Effects on aquatic fauna and plant growth; deposits of ochre in drainage pipes and ditches due to iron discharge
  • Significantly increased sulphate concentrations in soil or leachate (limit/threshold values may be exceeded: the threshold value for groundwater according to GrwV (German Groundwater Ordinance) is 250 mg/l)
  • High risk of corrosion to concrete and steel structures

*Geofacts 25

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