ASTM Proposes New Infrastructure Standards

THURSDAY, NOVEMBER 30, 2023


ASTM International’s composite materials committee has recently developed and proposed two new standards regarding alternative non-metallic materials that are applied to concrete structures for civil and infrastructure uses.

According to the release from ASTM’s D30 committee, the two proposals have direct practical applications to newly built infrastructure.

About the New Standards

The first proposed standard is referred to as WK83812 and is expected to be used to help stop concrete cracking and delamination with a composite mesh sheet. The release adds that this sheet would be used to prevent spalled pieces of concrete from falling off the concrete surface. 

This is expected to reduce the hazard and damage caused by the impact of concrete debris/pieces to vehicles or pedestrians when applied to elements such as bridge floor slabs, girders, wall balustrades and box culverts.

“These proposed standards will help further implement non-metallic materials, while supporting stakeholders properly select composites for their built infrastructure products,” said ASTM member Francisco De Caso.

“While these materials are well-established in many other industries, such as aerospace, automotive, and communications; wide adoption has not reached the civil engineering community, in part due to lack of specifications, such as the proposed standards.”

The second proposed standard is named WK87882 and is being implemented because of the surge of implementation of fiber reinforced polymer (FRP) reinforcement bar in the construction industry. 

The release states that glass and basalt FRP is currently used as internal concrete reinforcement, as described in a recently approved D30 specification standard (D8505/D8505M). Because of this, WK87882 is expected to give the specifications the use of carbon FRP bars, strands and spirals, for use as both a regular concrete reinforcement and a prestressed application.

“It is worth noting that, to date, hundreds of construction projects have been completed using both the non-metallic composite mesh and the CFRP bars/strands,” said De Caso. “These proposed standards build on this experience to enable adaptation by stakeholders across the construction industry.”

ASTM states that these new proposals relate to the United Nations Sustainable Development Goal #9 on industry, innovation and infrastructure, as well as several of the other U.N. goals.

More ASTM Proposals

In February, ASTM International announced that it was developing a proposed standard that would be used to help measure the tensile strength of fiber-reinforced concrete.

The standard, which was being developed by the Concrete and Concrete Aggregates Committee (C09), reportedly gave the engineering community the data and confidence needed to evaluate the performance of fibers.

ASTM International member Luke Pinkerton reported that the use of fiber reinforcement as an alternative to conventional reinforcement of various concrete structures had been limited in the construction industry.

According to the release, the effort also directly related to the United Nations Sustainable Development Goal #9.

The scope of the “New Practice for Direct Tension Testing of Fiber Reinforced Concrete” focused on three key points:

  • This practice evaluated the direct tension performance of fiber-reinforced concrete using parameters derived from the load-displacement curve, which was obtained by testing a tensile coupon under direct tension loading using a closed-loop, servo-controlled testing system. This practice provided for the determination of a load-versus-displacement curve. The results may have been normalized based on the number of fibers in the broken specimen cross section;
  • The values stated in either SI units or inch-pound units were to be regarded separately as standard. The values stated in each system were not to be exact equivalents; therefore, each system was to be used independently of the other. Combining values from the two systems may result in nonconformance with the practice; and
  • This practice did not purport to address all of the safety concerns, if any, associated with its use. It was the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

The draft standard also noted that there is currently no ASTM standard to measure this fundamental property of fiber-reinforced concrete, and tension could only be determined indirectly through flexural testing.

ASTM further explained that a direct testing method was needed to give the engineering community the data and confidence needed to evaluate performance of fibers. Additionally, the Committee added that direct tension testing methods were under development in other countries by competing standards organizations, and the development of a direct tension method would help maintain ASTM as a leader in the field.

Then, in June, ASTM International’s concrete and concrete aggregates committee (C09) reported that they were developing a standard to evaluate the tensile performance of fiber-reinforced concrete using “cylindrical specimens with double-punch loading.”

The method was reportedly based on the double-punch test method (DPTM), the process of loading a cylindrical specimen “with a length-diameter ratio of 1” into a compression testing machine through 1.5-inch diameter holes at the end.

According to Shih-Ho (Simon) Chao, a professor of civil engineering at the University of Texas at Arlington and member of ASTM, the DPTM is reportedly highly regarded since it had undergone extensive testing by researchers across the world.

The proposed standard would reportedly contain “pre- and post-peak tensile properties (that) hold great significance in fiber-reinforced concrete (FRC) and ultra-high-performance concrete (UHPC). These properties served as the fundamental characteristics of FRC and UHPC, playing a vital role in determining the capacities and failure modes of structural members constructed from these materials,” said Chao.

Chao added that FRC and UHPC can provide better durability over traditional concrete, which he stated “has the potential to encourage the adoption of these durable materials, thereby promoting sustainable development within society, particularly in terms of sustainable infrastructure."

   

Tagged categories: ASTM; Building materials; Certifications and standards; concrete; Construction; Infrastructure; Infrastructure; NA; North America; Program/Project Management; Safety; Testing + Evaluation

Join the Conversation:

Sign in to our community to add your comments.