Shaping Modern Infrastructure
For 100 years, C09 has developed concrete standards that are essential to the world's infrastructure.
When the members of ASTM International Committee C09 on Concrete and Concrete Aggregates celebrate the group's centennial anniversary this year, they can look back on a body of work highlighted by diligence, industry cooperation and market responsiveness while also taking aim at a future agenda filled with new goals and continued innovation.
From its founding in 1914 and through the decades that have followed, ASTM Committee C09 has made an enduring impact throughout the global construction, industrial, transportation, defense, utility and residential sectors. Concrete is the most widely used man-made product in the world, forming the backbone of homes, office buildings, bridges, sidewalks, superhighways, dams and more. Over six billion tons of concrete are produced annually. And for 100 years, the test methods and specifications developed by Committee C09 have helped to ensure the quality, durability and sustainability of this vital material and advance the application of new technologies in the concrete industry.
Today, Committee C09 has more than 1,400 members from 62 countries worldwide who manage a growing portfolio of more than 176 standards. The overall scope of C09 focuses on assembling and studying data pertaining to the properties of hydraulic-cement concrete and its constituent materials as well as the development of standards for concrete and the constituent materials of concrete (except cement). Standards development activities take place across 50 subcommittees in four main groups: materials, systems, testing and administration. While C09 efforts over the years have brought forth an impressive array of standards in such areas as ready-mixed concrete, self-consolidating concrete, chemical admixtures, supplementary cementitious materials, pervious concrete and much more, some members are eager to celebrate the journey just as much as the results.
"Looking at C09's book of standards alone doesn't tell the complete story of the committee's success and accomplishments over the past century," notes long-time member Richard Szecsy, Ph.D., P.E., president of the Texas Aggregates and Concrete Association and chairman of Subcommittee C09.40 on Ready-Mixed Concrete. "To produce the defining concrete industry documents that stakeholders around the world rely on every day has taken countless hours of dedicated effort and cooperation from thousands of international experts. Over the years, C09 has embodied everything that is great about the ASTM process. That itself is truly worth celebrating."
The foundation for Committee C09's cooperative efforts with the concrete industry came early in the committee's evolution through a partnership with the American Concrete Institute. The long-standing agreement between ASTM International and ACI was first established in 1936 and provides that standards focused on engineering design and concrete construction will be the purview of ACI while ASTM has the responsibility for the development of test methods for concrete, concrete products and constituent materials.
Having endured and grown for nearly eight decades, the partnership between ASTM C09 and ACI has been enormously beneficial for safe construction around the world. Numerous C09 standards are referenced in ACI standards, including its flagship code specification: ACI 318, Building Code Requirements for Structural Concrete. Fifty-eight ASTM standards are embedded in ACI 318, strengthening its utility as the model code that provides the legal framework for local and state building regulations throughout the United States.
ASTM C09 and ACI also cooperate on a wide range of certification programs designed to form a minimum qualification for personnel employed in the concrete construction industry. Certification efforts are aided by ASTM's construction materials technician training, which provides comprehensive training focused on construction material testing. ASTM training modules demonstrate proper concrete testing procedures and are consistent with national certification programs.
Concrete industry veterans Anthony Fiorato, Ph.D., and James Pierce, both long-time C09 members, have had the unique opportunity to witness the influence of the longtime ASTM/ACI relationship from both sides. Fiorato and Pierce both are former presidents of ACI and past chairmen of Committee C09, and they have served on the ASTM board of directors. "ASTM and ACI bring great synergy and collective expertise in serving the standards needs of the concrete industry," says Fiorato. "Their efforts have laid the groundwork for safe and reliable concrete design and construction practices around the world."
Pierce emphasizes that the relationship has thrived because of its member-driven focus. "The hard-working members of both ASTM and ACI deserve the credit for the partnership's long-term success. They have evolved and enhanced a very equitable and workable agreement to jointly deliver valuable technical standards to the marketplace."
For many years, Committee C09 has also worked closely with ASTM Committee C01 on Cement on their often synergistic missions. Among their areas of collaboration is the joint sponsorship and management of the ASTM International Cement and Concrete Reference Laboratory, which operates programs that promote the quality of testing at construction materials laboratories. CCRL's laboratory inspection and proficiency sample programs provide laboratories with mechanisms for determining the quality of their work in testing concrete and concrete aggregates, hydraulic cement, steel reinforcing bars, pozzolans and masonry materials according to ASTM standards. CCRL serves nearly 2,000 laboratories around the globe.
When reviewing the important contributions of C09 during the past century, ASTM members and industry stakeholders quickly point to the committee's first, and arguably still most important, standard today: C94/C94M, Specification for Ready-Mixed Concrete.
With properties that can be customized for different applications and durability to withstand diverse environmental conditions, ready-mixed concrete is one of the most widely utilized building materials. It is batched for delivery from a central plant instead of being mixed on the job site. Each batch is tailor-made according to the specifics of the contractor and is delivered to the contractor by truck in a plastic condition. According to the National Ready Mixed Concrete Association, the value of ready-mixed concrete produced by the industry is estimated at $30 billion annually.
Early members of Committee C09 tackled the area of ready-mixed concrete as one of their initial major actions. The committee approved the first version of standard C94 in 1933, covering many of the fundamental topics involving mixing and hauling that are still part of C94 decades later. The standard has been revised many times since its first release and continues to undergo revisions to remain in step with such technological advances as load-cell weighing and such environmental issues as limiting plant runoff water by the use of nonpotable water in the batching process. One thing that has not changed is C94's preeminent role in the concrete industry.
"C94 is one of the most important, universally accepted standards around the world for concrete manufactured and delivered to a purchaser in a freshly mixed and unhardened state," says Pierce.
Committee C09's responsiveness to the concrete industry was further evidenced in the release of two additional standards related to ready-mixed concrete. Since concrete is one of the few building materials whose quality and performance characteristics can be altered after it is transported from the manufacturing facility, testing requirements and qualifications for the use of water - especially recycled water - are crucial. For years, the concrete industry had grappled with establishing better practices for the addition of water to concrete on the job site. At the same time, tighter environmental regulations surrounding the management and use of discharged water at concrete production facilities heightened the need for standards for the manufacturing community.
In 2004, the members of Committee C09 filled the void, releasing two companion standards that - for the first time - specified the use of water in the production of ready-mixed concrete. Designers, contractors and concrete producers now rely on ASTM C1602/C1602M, Specification for Mixing Water Used in the Production of Hydraulic Cement Concrete, to help define the compositional and performance requirements for various sources of water used in the mixing of hydraulic cement concrete. Further utility is offered by ASTM C1603, Test Method for Measurement of Solids in Water, which is used to determine the solids content of mixing water used to produce concrete when one or more of the water sources is wash water from concrete production operations or water that contains solids.
Szecsy, who was closely involved in the development of C1602 and C1603, views the release of the two standards as one of most significant events in his tenure on the committee. "For a long time, there was a belief that water was just another ingredient in producing ready-mixed concrete, without deeper consideration to the various water sources. To better ensure the long-term performance of products and to address growing environmental pressures on manufacturers, standards were sorely needed. Thanks to C1602 and C1603, all industry stakeholders have proven tools to better manage and use all of their potential water sources without compromising the concrete's durability."
Chemical admixtures, such as water reducers, retarders and accelerating agents, which are added to concrete immediately before or during mixing, play a vital role in improving the characteristics and durability of concrete. Producers use admixtures primarily to modify the properties of hardened concrete\; control strength development\; ensure quality during mixing, transporting, placing and curing\; and enhance finish. In cold weather environments in particular, admixtures can accelerate the setting time of concrete to avoid freezing and provide enhanced frost and sulfate resistance. The National Ready Mixed Concrete Association estimates that 80 percent of concrete produced in North America contains one or more types of admixtures.
Several C09 subcommittees are actively engaged in advancing and supporting the use of admixtures and supplementary materials in concrete production, including C09.23 on Chemical Admixtures, C09.24 on Supplementary Cementitious Materials, C09.27 on Ground Slag and others.
Among the notable C09 standards in this field are C494, Specification for Chemical Admixtures for Concrete, which is the most widely accepted guide for admixture usage among concrete producers. C494 covers the materials and the test methods for use in chemical admixtures to be added to hydraulic-cement concrete mixtures in the field and defines seven common types of admixtures. Another C09 standard providing related utility is C260/C260M, Specification for Air-Entraining Admixtures for Concrete. Air entrainment, the creation of tiny bubbles in concrete, increases the durability of the hardened concrete, especially in climates subject to freeze-thaw cycles.
Although concrete is deeply entrenched in the global construction industry, concrete technology continues to move forward. As these technologies develop and advance over time, the members of Committee C09 have remained resilient and steadfast in their commitment to be responsive to the standards needs of its stakeholders. Long-time members of Committee C09 see this responsiveness as job number one.
"During my 20 years as a member of Committee C09, there has been an ongoing evolution in concrete technology," notes Steven E. Parker, North American sales and marketing manager at CHRYSO Inc., and current C09 chairman. "I believe that maintaining pace with these advancements and delivering standards that are directly relevant to industry needs has been and continues to be our top priority as a committee."
In recent years, the committee has seen growing interest and demand for self-consolidating concrete technology. SCC is highly workable concrete that can flow through densely reinforced and complex structural elements under its own weight and adequately fill all voids without segregation, excessive bleeding, excessive air migration (air popping) or other separation of materials, and without the need for vibration or other mechanical consolidation. From an installation standpoint, SCC offers many benefits over conventional concrete, including reduced labor requirements, quicker production rates and lower project costs.
Addressing the advent of this concrete technology, C09 formed Subcommittee C09.47 on Self-Consolidating Concrete to develop standards in this evolving area. Through its focused agenda, C09.47 has delivered a number of valuable standards to the marketplace, including C1712, Test Method for Rapid Assessment of Static Segregation Resistance of Self-Consolidating Concrete Using Penetration Test. This standard helps concrete producers develop quality control procedures when measuring and maintaining the stability of self-consolidating concrete mixtures. Another well-referenced standard is C1610/C1610M, Test Method for Static Segregation of Self-Consolidating Concrete Using Column Technique.
The developing topic of alkali-aggregate reactions in concrete has also been taken up on Committee C09's standards development agenda. AAR is a chemical reaction of alkali in concrete and certain alkaline reactive minerals in aggregate producing a hygroscopic gel which, when moisture is present, absorbs water and expands. Gel expansion causes cracking in the concrete, resulting in major structural problems and sometimes necessitating demolition.
AAR is the focus of subcommittee C09.50 on Risk Management for Alkali Aggregate Reactions. The group is spearheading the development of standards on the mitigation of deleterious alkali-aggregate reactions in concrete. C09.50's first standard is currently in development and will address the process of identifying both potentially alkali-silica reactive and alkali-carbonate reactive aggregates through standardized testing procedures and the selection of mitigation options.
Continued growth in sustainable building design and construction is also helping fuel many dynamic initiatives within Committee C09. One area that is drawing increased attention is the use of fly ash as an admixture in concrete production. Fly ash is a byproduct from burning pulverized coal in electric power generating plants. When used in concrete production, it improves workability, cohesiveness, finish and durability while also consuming less energy, improving efficiency and enhancing building performance - all important goals in green construction. Currently, fly ash is used in more than 50 percent of all ready-mixed concrete placed in the United States, according to data from the National Ready Mixed Concrete Association.
Committee C09 has developed several standards to assist industry stakeholders in the selection, testing and blending of fly ash in concrete production, ultimately supporting greater concrete usage and furthering sustainable practices. C1697, Specification for Blended Supplementary Cementitious Materials, provides core guidance for blending of two or three ASTM compliant supplementary cementitious materials, including coal fly ash, for use in concrete or mortar. This standard is used in conjunction with two fly ash standards: C311/C311M, Test Methods for Sampling and Testing Fly Ash or Natural Pozzolans for Use in Portland-Cement Concrete, and C618, Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete.
An important consideration in sustainable construction is also the proper management of stormwater. Impervious surfaces typically found in residential driveways, sidewalks and urban parking lots are susceptible to large amounts of stormwater runoff, which can have harmful environmental impacts: increased pollution and frequent flooding, stream channel instability, concentration of flow on adjacent properties, and damage to transportation and utility infrastructure.
To address these challenges, green building developers are turning to pervious concrete, an environmentally friendly solution for the surfaces of streets, driveways and parking areas that are part of or adjacent to homes and office buildings. Pervious concrete captures stormwater and allows it to seep into the ground, reducing runoff and helping to meet U.S. Environmental Protection Agency stormwater regulations.
Subcommittee C09.49 on Pervious Concrete is filling the market need for standards for pervious concrete. As a result of its porous nature, pervious concrete cannot be tested using traditional concrete standards. Filling the void is C1688/C1688M, Test Method for Density and Void Content of Freshly Mixed Pervious Concrete, which helps verify that the pervious concrete delivered to a project corresponds to the producer's mix proportions\; and C1701/C1701M, Test Method for Infiltration Rate of In Place Pervious Concrete, which is used to detect a reduction of infiltration rate of the pervious concrete, thereby identifying the need for remediation.
Along with the global growth in sustainable building construction has come a rise in "green" product claims from material manufacturers and other industry suppliers. One of the key tools available to help manufacturers assess the true greenness of their products is the environmental product declaration - a detailed report outlining a product's effect on the environment over the course of its lifetime.
In 2012, ASTM International became a program operator for developing product category rules and verifying EPDs in response to the growing need to understand the real environmental impact of products from raw material extraction to disposal and recycling. Committee C09 members are supporting ASTM lead stakeholder groups in this effort, providing specific industry knowledge to the development process for PCRs for concrete and concrete aggregates. ASTM is currently working with numerous concrete industry organizations in developing PCRs and verifying new EPDs, including the Portland Cement Association, Slag Cement Association, National Concrete Masonry Association and several others.
In a year of celebration, the accomplishments and contributions of ASTM Committee C09 to the global concrete and construction industries, and the built environment as a whole, could fill many more pages of this magazine. From its promising beginnings in 1914 when a small group of professionals gathered to work on methods for making and testing field specimens of concrete\; to its international membership of more than 1,400 technical experts addressing today's dynamic industry challenges, Committee 09 and its members - past and present - can reflect on its accomplishments and its ongoing work to meet standards needs.Doug Clauson is a freelance writer based in Wynnewood, Pa.