Hello everyone,
A potential plot for a single-family house presents the following challenges:
- The groundwater is at a depth of 3.5 m (11.5 ft). In theory, it could rise to a depth of 2.2 m (7.2 ft). Part of the planned basement would therefore be below the groundwater level.
- In addition, the soil is contaminated with sulfate (260 mg/l).
A watertight concrete structure (commonly known as a “white tank”) is planned.
- Does the sulfate content (260 mg/l) pose a problem?
- How significantly does the sulfate concentration affect the durability of the watertight concrete structure? What is the expected service life of such a structure under the given conditions (groundwater, sulfate)?
I would appreciate your opinions very much.
A potential plot for a single-family house presents the following challenges:
- The groundwater is at a depth of 3.5 m (11.5 ft). In theory, it could rise to a depth of 2.2 m (7.2 ft). Part of the planned basement would therefore be below the groundwater level.
- In addition, the soil is contaminated with sulfate (260 mg/l).
A watertight concrete structure (commonly known as a “white tank”) is planned.
- Does the sulfate content (260 mg/l) pose a problem?
- How significantly does the sulfate concentration affect the durability of the watertight concrete structure? What is the expected service life of such a structure under the given conditions (groundwater, sulfate)?
I would appreciate your opinions very much.
The composition of concrete is determined based on its classification into an "exposure class," which summarizes all external stresses. There are various DIN standards, guidelines, etc., related to this. A sulfate content of 260 mg/l corresponds to the lowest exposure class "XA1," which is met with a specified water-cement ratio and a compressive strength class of C25/30, representing a standard quality. Defining the concrete quality is the responsibility of the planner.
An excerpt from the cement datasheet Concrete Technology B 9-9.2014
“When concretes are classified into exposure classes XA2 or XA3 due to increased sulfate concentrations, the measured sulfate concentration must always be specified because, depending on the sulfate level, sulfate-resisting (SR) cements or cement-fly ash mixtures may need to be used. Therefore, concrete manufacturers require the sulfate concentration measurement to determine an appropriate concrete composition.
Concrete for exposure class XA3 must also be protected from direct contact with aggressive substances unless an expert report demonstrates the suitability of another solution. Protective measures may include protective layers (paint, coatings) or permanent claddings (waterproof membranes made of plastic sheets or impregnated/coated cardboard, panel claddings).”
An excerpt from the cement datasheet Concrete Technology B 9-9.2014
“When concretes are classified into exposure classes XA2 or XA3 due to increased sulfate concentrations, the measured sulfate concentration must always be specified because, depending on the sulfate level, sulfate-resisting (SR) cements or cement-fly ash mixtures may need to be used. Therefore, concrete manufacturers require the sulfate concentration measurement to determine an appropriate concrete composition.
Concrete for exposure class XA3 must also be protected from direct contact with aggressive substances unless an expert report demonstrates the suitability of another solution. Protective measures may include protective layers (paint, coatings) or permanent claddings (waterproof membranes made of plastic sheets or impregnated/coated cardboard, panel claddings).”
Similar topics