Petrography
Petrographic Analysis of Concrete, Aggregate & Other Construction Materials
We are the world’s leading testing, inspection and certification company. Our petrographic analysis lab has operated for more than 20 years and maintains ISO 17025 and AASHTO laboratory accreditations.
Our team of expert petrographer, geologist, and engineers actively contributes to the advancement of industry standards through participation in ASTM and other regulatory organizations. Our specialists hold leadership and committee positions within ACI, ASTM, ICRI, FRCA, ASCE, and SWRI, bringing practical field experience and technical expertise to every project.
Petrographic examination provides the detailed material insights needed to make confident, standards-based decisions. Using advanced microscopic examination techniques, our petrographers evaluate concrete, aggregate, rock, mortar, and other cementitious materials to determine their composition, quality, and condition.
Petrography can reveal how a material was manufactured, identify the causes of deterioration or distress, and help explain unexpected performance, support effective troubleshooting, quality assurance, and forensic investigations.
The results help engineers, contractors, and owners diagnose problems, verify material quality, support failure investigations, and make informed decisions about repair and long-term durability.
Ready to learn more?
Accredited Laboratory
ISO/IEC 17025 American Association for Laboratory Accreditation
AASHTO Accreditation Program (R18)
Members of American Society for Testing & Materials
Petrography Testing
Our petrography laboratory provides a comprehensive range of testing services. These are some of the most frequently requested tests performed.
Petrographic Examination of Hardened Concrete
ASTM C856
ASTM C856 applies to samples of all types of hardened hydraulic-cement mixtures, including concrete, mortar, grout, plaster, stucco and more. Common tests include:
- Water Content
- Air Content
- Chemical Attack
- Alkali Silica Reactions (ASR)
- Freeze Thaw Damage
- Paste Carbonation
- Corrosion of Rebar
- Fire Damage
- Cause of Cracking
- Sulfate Attack
- Improper Finishing
- Fly Ash, Slag, Silica Fume
- Aggregate Lithology
- Specification Compliance
- Service Life
Petrographic Examination of Aggregates
ASTM C295
ASTM C295 is the test method for petrographic examination of aggregates used in cementitious mixtures, such as concrete and can include:
- Alkali-Silica Reactivity (ASR) Potential
- Alkali-Carbonate Reactivity (ACR) Potential
- Aggregate Lithology (Rock Type)
- Durability
- Staining Potential
- Rock Core Petrography
- Quarry Approvals
- Mica Content
- Quality
- Water Demand Effects
- Pyrrhotite Content
Petrographic Examination of Masonry Mortar
ASTM C1324
ASTM C1324 is the test method for petrographic examination and chemical analysis of hardened masonry masonry mortar. Our lab performs:
- Sand lithology, gradation, texture, and color
- Type of cementitious material and lime content
- Air content and presence of entrained air voids
- Porosity, quality, and durability
- Equivalent ASTM C270 mortar type
- Indications of previous repointing material
- Recommended proportions of repointing mortar
Related Services
- X-Ray Diffraction (XRD)
- Concrete Testing
- Aggregate Testing
- Petrography Laboratory
- Construction Materials Testing Lab
Related Resources
Related Articles
Frequently Asked Questions About Petrography
Our petrographer typically use:
• Visual examination of the sample
• Stereo microscopy to inspect surfaces and fracture features
• Polarized light microscopy to examine thin sections of the material
• High-resolution photography and photomicrographs
• Sometimes supplemental testing such as chemical analysis or scanning electron microscopy (SEM)
A petrographic examination can help answer questions such as:
- Why are my compressive strength values less than the design?
- How do I know the provided concrete matches the mix design?
- Was too much air entrainment added to the concrete?
- Is it time to remove and replace the existing concrete slab?
- Why do I have so much efflorescence on my concrete?
- Did the material quality contribute to the building collapse?
- What is the condition of the concrete in the old building?
- What is the probable future performance of my concrete?
- Why is my slab surface color blotchy?
- How much surface preparation is required?
- Why are there so many cracks in my slab?
- Why did the surface of the concrete flake off?
- What materials were used in the historic mortar?
- Can this aggregate be used in concrete?
- Why is this concrete cracking?
- Is the aggregate causing deterioration?
- Was the concrete made according to the specified mix design?
- Is there evidence of poor workmanship or improper curing?
- Is this an alkali-silica reaction (ASR)?
- Has freeze-thaw damage occurred? • Is sulfate attack present?
- Are there signs of delayed ettringite formation (DEF)?
- Why did this pavement, bridge deck, or structure fail prematurely?
- What minerals are present in the aggregate?
ASTM C856: Used for hardened concrete investigations ASTM C856 is the standard practice for petrographic examination of hardened concrete.
ASTM C295: Used to evaluate aggregates before use or during failure investigations. ASTM C295 is the standard guide for petrographic examination of aggregates for concrete.
ASTM C1324: Used for mortar analysis. ASTM C1324 is the standard test method for examination and analysis of hardened masonry mortar.
Petrography is the microscopic analysis of rocks, minerals, and other materials used to determine their mineralogical composition, fabric, and physical characteristics. By preparing samples as thin sections and examining them under optical and analytical microscopes, petrographers can characterize constituent phases, assess material performance, and investigate the causes of degradation and failure.
Petrography is most valuable during:
- Failure investigations – determining why a structure deteriorated.
- Pre-construction material qualification – assessing aggregate suitability.
- Litigation and insurance claims – providing independent technical evidence.
- Condition assessments – evaluating existing structures.
- Quality assurance and troubleshooting – verifying materials and workmanship.
Used by engineers, consultants, contractors, DOTs, attorneys, and owners, petrography often provides the evidence needed to answer the most important question: “What happened, and why?”
