AASHTO T288

AASHTO T288 is a laboratory procedure used to determine the minimum resistivity that a soil may exhibit under varying moisture conditions.

The standard is specifically designed to identify the lowest resistivity condition likely to occur within a soil sample because this condition is often associated with the highest corrosion potential. 

The method involves:

• sample preparation 
• particle size reduction 
• controlled moisture additions 
• repeated resistivity measurements 

The lowest measured resistivity value is reported as the minimum soil resistivity.

Corrosion can significantly reduce the service life of buried metallic assets.

AASHTO T288 testing may support evaluations involving:

• steel pipelines 
• ductile iron pipes 
• water mains 
• transmission towers 
• grounding conductors 
• underground storage systems 
• buried steel foundations 
• utility infrastructure 

Understanding soil resistivity helps engineers identify environments that may accelerate corrosion.

Unlike a simple field resistivity measurement, AASHTO T288 progressively increases the moisture content of the sample until the lowest resistivity value is identified.

The standard recognizes that the most corrosive condition may not occur at the natural moisture content observed at the time of sampling.

By identifying the minimum resistivity condition, engineers can evaluate the worst-case corrosion potential of the material.

Although originally developed for soils, the methodology can also provide valuable information regarding the electrical behavior of aggregates and engineered backfill materials.

Applications may include:

• utility installations 
• buried infrastructure projects 
• corrosion-sensitive environments 
• specialty aggregate qualification 

This is where you can legitimately connect to your aggregate resistivity capability without overstating grounding applications.

AASHTO T288 testing is frequently requested by:

• geotechnical engineers 
• corrosion engineers 
• municipalities 
• utility companies 
• pipeline operators 
• consulting engineers 
• transportation agencies 
• infrastructure owners 

Typical projects include:

• buried utility installations 
• pipeline corridors 
• municipal infrastructure 
• corrosion investigations 
• soil characterization programs 
• environmental and geotechnical studies

Soil resistivity is one of the most commonly used indicators when evaluating the potential corrosivity of soils surrounding buried metallic infrastructure.

AASHTO T288 provides a standardized laboratory procedure for determining the minimum resistivity that a soil may exhibit under varying moisture conditions. The resulting data can assist engineers and asset owners in evaluating environmental conditions that may contribute to corrosion of buried steel, ductile iron and other metallic infrastructure.

LAB-ELITE supports municipalities, utility companies, engineering consultants and infrastructure owners by providing reliable AASHTO T288 resistivity testing services for soils, aggregates and engineered backfills throughout Quebec and Canada.

• Buried pipelines 
• Water mains 
• Utility corridors 
• Underground storage systems 
• Steel foundations 
• Transmission infrastructure 
• Corrosion investigations 
• Asset management programs

Low soil resistivity values are often associated with environments that may accelerate corrosion of buried metallic infrastructure. For this reason, electrical resistivity testing is frequently performed together with:

• Soil pH testing 
• Soluble chloride analysis 
• Soluble sulfate analysis 
• Moisture content determination 
• Geotechnical characterization 

Combining these parameters can provide a more comprehensive understanding of soil aggressiveness and long-term infrastructure durability.

LAB-ELITE offers integrated analytical testing programs to support corrosion assessments and infrastructure investigations.