The Concrete Insight team uses concrete petrography and other analytical methods to investigate concrete and other cement-based construction materials, natural rock products, and geological resources. With straightforward thinking, meticulous detail, and impeccable customer service, we provide our clients the information they need to understand the performance of construction materials.

Petrographic examination is useful for identifying aggregates that are susceptible to alkali-aggregate reactions, lack freeze-thaw durability, are soft or incompetent, have deleterious coatings or excessive fines, and more. DRP has extensive experience with aggregate QA/QC for use in concrete or other cement-based materials following procedures described in ASTM C295, Guide for Petrographic Examination of Aggregates for Concrete. We have done petrographic examination on aggregates from all over North America, Central and South America, Asia, and scattered Pacific Islands.

Our team of experts are available to provide a wide range of solutions your concrete projects from providing quality assurance to diagnosing causes of deterioration. With extensive experience in concrete materials and early age problems, durability mechanisms, and the performance of slabs ranging from pavements to industrial floors, we help engineers formulate solutions that range from minor repairs to removal and replacement. We can provide:

We routinely perform petrographic analyses on aggregates and microscopical air void analyses to help provide quality assurance of ready-mixed and precast concrete elements. We have extensive experience in troubleshooting early-age issues such as unusual setting behavior, curing issues, low strength and cracking.

• Concrete Aggregates
• Air Void Analysis
• Early Age Cracking
• Strength

Our team is available to sort out complex problems regarding durability issues that include alkali-aggregate reaction, sulfate attack, salt weathering, freeze-thaw damage and scaling, chemical attack, corrosion and more.

• Alkali-Aggregate Reaction
• Sulfate Attack
• Salt Weathering
• Scaling
• Freeze-Thaw Damage
• Chemical Attack
• Carbonation and Corrosion

You can rely on our team’s experience in working with slabs and pavements that show excessive cracking, delamination, blisters, low wear resistance and other surface defects. We are also seasoned investigators of moisture migration issues and floor covering failures.

• Surface Defects
• Floor Coverings

Electron Microscopy Scanning

Electron Microscopy Scanning (EMS) allows our team to examine materials at higher magnifications and with superior resolution than optical microscopes. When equipped with energy-dispersive x- ray spectrometers (EDS), the electron microscope allows in situ determinations of the chemical composition of an area of interest. Our Concrete Insight experts possess extensive experience in the use of SEM/EDS methods to study microstructural aspects of cement hydration and strength development, fly ash quality and characteristics, and durability mechanisms that include sulfate attack, alkali- aggregate reactions, salt weathering and freeze-thaw damage as influenced by deicers.

Condition Surveys

Twining’s team of experts have a background in geological field work, which hinges on the compass, offers a seamless translation to investigating concrete in the field. We have extensive experience looking at flooring failures, stucco failures, excessive cracking, and a host of durability mechanisms in the field. This capability enhances the development of sound sampling plans and contributes key observations that help link findings under the microscope to performance in the field.

Optical Microscopy

One of Concrete Insight’s core competencies is classical petrography, which is the branch of geology that deals with the systematic description of rocks and minerals. Optical microscopes, which manipulate photons to produce the images that inform our understanding of the performance of a material, serve as the foundation of our work. In our flagship office in Boulder, CO, we house a full complement of Nikon microscopes for stereomicroscopy, transmitted light microscopy and air void analyses.

Electrical Resistivity

Our team uses bulk electrical resistivity for a variety of purposes relevant to assessing the quality and durability of cementitious materials. Bulk resistivity measurements are the foundation of the Formation Factor, which provides a robust method to evaluate the potential durability of a concrete mixture. The Formation Factor is a central pillar in determining transport properties of concrete mixtures and developing service life models of the time to reach chloride corrosion thresholds for embedded steel reinforcement. Finally, we use bulk resistivity with residual expansion testing and quantitative microcracking measurements to the potential for damage to occur in concrete affected by alkali-aggregate reaction.

Fluorescence

Concrete Insight uses fluorescent microscopy to highlight key aspects of concrete in both reflected and transmitted light. We use epoxy with fluorescent dye to stabilize fragile and damaged samples, which allows us to observe and document cracks and microcracks on polished slabs with great resolution. We produce thin fluorescent sections to the highest standards that allow us to measure the w/cm of hardened cementitious materials.