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At Durability Engineers, our engineers and materials scientists are regularly implementing, evaluating and investigating changes in our industry. Our comprehensive understanding  of concrete materials used in the field is further leveraged by our laboratory experience and involvement in the industry organizations that develop construction practices and testing methods for concrete and concrete constituents . We use this knowledge to assists our clients evaluating and performing specialized testing for the development of novel building concepts and products.

Image by Scott Graham


pir-uh-tahyt - Fe(1-x)S (x=0 to 0.2) - is an iron sulfide mineral that occurs as a trace constituent in many igneous, sedimentary, and metamorphic rocks.  The iron sulfide reacts with water and oxygen inside concrete elements, causing staining on exposed surfaces and cracking of the concrete.

In cold regions, concrete structures containing pyrrhotite have been shown to be susceptible to more severe mechanisms of degradation due to internal sulfate attack, resulting in degradation of the cement paste and loss of structural capacity.

What is Our Approach?


The Durability Engineers Building Materials Laboratory provides advanced testing and forensic capabilities to solve the complex  problems with construction materials and structures.  Equipped with state-of-the-art equipment for standardized and specialty testing and applied research.  The laboratory includes equipment for chemistry, petrography, mortar, concrete, corrosion, and structural testing.

  • Cement and Supplementary Cementitious

  • Aggregate Testing

  • Concrete and Materials Testing

  • Durability and Specialty Testing

Cement powder in bag before mix. Concrete texture background.jpg
Laboratory Testing
Image by Misael Moreno


Durability Engineers, in partnership with RJ Lee Group, performs  petrographic examinations and laboratory analyses to investigate material failures, incompatibilities, and deterioration of cementitious materials, aggregates, mortars, grouts, and concretes.  Petrographic analysis uses stereo, petrographic, and scanning electron microscopes to examine and evaluate the optical properties and microstructural characteristics of the materials.

Petrographic Services
Pyrrhotite Test Methods


Durability Engineers tests materials in accordance with CSA specifications such as:

CSA A23.1:19 P2 Test Method for Detection of the Oxidation Potential of Sulphide-Bearing Aggregates by an Oxygen Consumption Test

CSA A23.1:19 P3 Test Method for Detection of Potential Reactivity of Sulphide-Bearing Aggregates by Accelerated Expansion of Mortar Bars

ASTM C295 Standard Guide for Petrographic Examination of Aggregates for Concrete

ASTM D4239 Standard Test Method for Sulfur in the Analysis of Sample of Coal and Coke using High Temperature Tube Furnace Combustion

ASTM D2492 Standard Test Method for forms of Sulfur in Coal


As quality aggregates become exhausted, quarries with less historical data and desirable aggregate properties are beginning to be utilized. In a recent article by the United States Geological Survey (USGS), the distribution of pyrrhottite in the United States was provided. In addition, the article discussed the lack of ASTM International standards for assessing allowable sulfur or sulfide mineral content for aggregates used in concrete. 

Durability Engineers Can Help...

Our team assists our clients through the development of standardized and specialty testing programs. 

USGS Map of Pyrrhotite Across the United States

Let's Work Together

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