This letter addresses the article titled “Refined Concrete, A Measurable Path to Performance and Sustainability,” published in the January 2026 edition of The Construction Specifier. The article raises important questions about terminology and performance in concrete floor finishing systems. Because specification language directly influences construction outcomes, several aspects of the article’s distinction between “polished” and “refined” concrete warrant technical clarification. It is incumbent upon both the Concrete Polishing Council (CPC) and the ASCC to provide these clarifications before the industry is affected by inaccurate information. Therefore, the CPC Technical Committee, part of the American Society of Concrete Contractors (ASCC), submits this for the record to ensure that accurate information is presented to the industry, which many developers, engineers, and contractors rely on.

In sum, the article suggests that introducing a separate category labeled “refined concrete” improves clarity and accountability in floor specifications. However, many of the characteristics described under this label—progressive mechanical refinement, densification, and measurable surface properties—are already fundamental elements of established polished concrete guidance.

The Concrete Polishing Association of America (CPAA)—now operating as CPC within the ASCC—was established in 2010 to support the development of technical guidance and best practices for mechanically polished concrete flooring.

CPC guidance is developed through collaboration among contractors, manufacturers, engineers, and other industry stakeholders. This framework reflects the same consensus-based approach used throughout the concrete industry for standards development. Further reinforcing this structure, CPC participates in ACI–ASCC Committee 390.1, which focuses on the specification and qualification of polished concrete floor finishes. The committee operates under the American Concrete Institute (ACI) standards process, which includes balanced stakeholder participation and formal technical review.

Clarifying industry terminology

The article at issue suggests that polished concrete is sometimes used as a broad or “catch-all” term for various floor-finishing methods. Within CPC guidance, however, polished concrete is defined as a mechanically processed concrete surface produced using progressively finer abrasive tooling to achieve measurable clarity and gloss.

This process differs fundamentally from flooring systems that rely on film-forming coatings or high-build sealers to achieve reflectivity. In specification practice, these systems are typically categorized separately as coated or sealed concrete flooring.¹

Clear terminology matters because different finishing systems rely on distinct performance mechanisms. Mechanical polishing produces surface reflectivity by progressively refining the concrete substrate, while coatings achieve reflectivity through applied films.

Maintaining this distinction enables design professionals to specify flooring systems more precisely and helps avoid confusion during construction.

Mechanical refinement and surface measurement

Mechanically polished concrete floors are produced through progressive abrasive refinement and densification of the cement matrix. Densifiers react with free lime in the concrete to form additional calcium silicate hydrate (C-S-H), increasing surface hardness and enabling further polishing steps.

On the contrary, finished surfaces can be evaluated using several established measurement methods. For example, surface gloss may be measured with gloss meters in accordance with ASTM D523, Standard Test Method for Specular Gloss. Additional optical instruments, including Distinctness of Image (DOI) meters and haze meters, may be used to evaluate clarity and light reflection characteristics. These tools measure the optical performance of the finished surface and provide repeatable indicators of reflectivity and surface refinement.

Some authors have suggested using stylus profilometers to characterize surface roughness. Profilometry is widely used for measuring micro-scale surface texture in uniform materials, such as machined metals. Concrete, however, is a heterogeneous composite material, consisting of cement paste, fine aggregate, and coarse aggregate. Because surface texture in concrete can vary due to aggregate exposure and finishing conditions, optical measurement tools that assess the overall reflective behavior of the surface are commonly used to evaluate the visual characteristics of polished concrete floors.

Interpreting Mohs hardness in concrete flooring

The article places considerable emphasis on Mohs hardness values in its description of refined concrete systems. The Mohs scale, introduced in 1812 by mineralogist Friedrich Mohs, ranks minerals according to their relative scratch resistance. While Mohs hardness can be useful for comparing mineral scratch resistance, it is important to recognize the limitations of the scale when applied to concrete flooring systems. The Mohs scale is:

• an ordinal ranking system, not a linear measurement scale
• primarily used for mineral identification
• not designed to measure abrasion resistance, compressive strength, or structural durability

Concrete is a composite construction material made of cement paste, aggregates, and supplementary materials. Because aggregates vary in mineral composition, localized scratch resistance may differ across a finished concrete floor.

For these reasons, Mohs hardness is not commonly used as a stand-alone performance classification metric within concrete flooring specifications.

Contractor practices and surface treatments

In the flooring industry, the informal term “pay-juice” is sometimes used to describe the misuse of surface treatments intended to compensate for incomplete polishing processes. Such practices typically occur when finishing procedures are abbreviated or when coatings are used to artificially increase surface gloss.

Professional polishing standards emphasize that surface clarity and reflectivity should result primarily from mechanical refinement of the concrete substrate. Protective treatments applied after polishing are typically intended to enhance stain resistance or simplify maintenance, rather than serve as the primary source of reflectivity.

Over the past two decades, millions of square feet of mechanically polished concrete floors have been installed in commercial, industrial, and institutional facilities. These installations demonstrate the viability of mechanically refined concrete flooring systems when properly specified and executed.

Maintaining clear distinctions between mechanically polished concrete and topical coating systems helps ensure that specifications accurately reflect the intended flooring performance.

Specification and performance criteria

Modern concrete flooring specifications increasingly rely on objective measurements and clearly defined processes to communicate performance expectations. Examples of measurable performance characteristics referenced in flooring specifications may include:

• Surface gloss measurements (ASTM D523)
• Slip resistance testing, such as ANSI/NFSI B101.3 dynamic coefficient of friction measurements
• Surface durability and abrasion resistance of the concrete substrate

When specifications clearly define these criteria, design professionals can communicate project expectations more effectively and reduce ambiguity during installation.

Organizations such as the American Concrete Institute (ACI), the American Society of Concrete Contractors (ASCC), and related industry groups continue to contribute to the development of guidance and best practices intended to support consistent performance in concrete flooring systems.

Conclusion

Discussion surrounding polished and refined concrete reflects the continued evolution of concrete flooring technology.

The distinction presented between “polished” and “refined” concrete, therefore, appears to describe differences in specification and execution rather than fundamentally different flooring technologies. Regardless of terminology, the key factors that determine flooring performance remain consistent:

• clear specification language
• appropriate mechanical surface preparation
• objective measurement of finished surfaces
• qualified contractors and consistent installation practices

Constructive dialogue within the industry is valuable, particularly when it supports clearer standards, improved specifications, and better outcomes for building owners and design professionals.

We appreciate the opportunity to contribute to this discussion.

American Society of Concrete Contractors (ASCC) Concrete Polishing Committee (CPC) Technical Committee: Roy Bowan, Cliff Rawlins, Carla Nickodemus, Ryan Atkinson, Bill Benker, Bob Harris, and Bruce Ferrel.

Notes

¹ Reflectivity in polished concrete is not created by applied films but by specular light reflection that occurs when progressive mechanical refinement reduces surface micro-texture and lowers the peak-to-valley surface profile of the concrete substrate.

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References

• American Concrete Institute (ACI). ACI–ASCC 390.1, Guide for Specifying Polished Concrete.
• ASTM International. ASTM D523, Standard Test Method for Specular Gloss.
• National Floor Safety Institute (NFSI). ANSI/NFSI B101.3, Test Method for Measuring Wet Dynamic Coefficient of Friction of Hard Surface Flooring Materials.
• American Society of Concrete Contractors (ASCC). Concrete Polishing Council (CPC) — Technical Guidance and Industry Resources.