News Detail

Advocating for Concrete

7/2/2018

In my first month as ACI President, I was presented with an opportunity to testify before the House Committee on Science, Space, and Technology, Subcommittee on Research and Technology, on the topic of advancing the use of fiber-reinforced polymer (FRP) materials in construction. The hearing was prompted by a 2017 workshop hosted by the National Institute of Standards and Technology (NIST), which resulted in NIST Special Publication 1218, Road Mapping Workshop Report on Overcoming Barriers to Adoption of Composites in Sustainable Infrastructure. The subcommittee hearing was designed to identify barriers and discuss how the federal government might play a role in addressing those barriers.

In addition to reviewing the report, I turned to ACI members to assist in the development of my testimony. Tony Nanni, FACI, Professor and Department Chair at the University of Miami, shared details about how ACI Committee 440, Fiber-Reinforced Polymer Reinforcement, was paving the way for FRP reinforcing bars to be more prominent as a solution to steel corrosion problems in aggressive environments. ACI member Doug Gremel, Owens Corning Infrastructure Solutions, armed me with information about ASTM D7957/D7957M, "Standard Specification for Solid Round Glass Fiber Reinforced Polymer Bars for Concrete Reinforcement," which was recently approved and made available for specifying FRP reinforcing bars. Larry Bank, FACI, City College of New York, provided me with a wealth of information about design of repairs using FRP products such as fiber-reinforced sheets that are used to strengthen concrete elements.

These are great examples of growth areas for FRPs within the concrete industry, but they are not entirely responsive to the concerns of the greater FRP industry as it seeks even more acceptance in heavy construction—seeing opportunities, for example, in the use of pultruded or molded shapes and shell structures made with FRP as alternatives for more traditional solutions for structural applications.

I observed in my testimony that two dominant paradigms—reinforced concrete and structural steel—exist for commercial buildings and bridges, as they have deep tradition, established trades, and design codes. The concrete-versus-steel decision has been with us for over 100 years, just as the concrete-versus-asphalt decision has been with us in paving applications. It is no surprise that industry and design professionals might find themselves advocating for one or another of these alternatives. In the question period of the hearing, I remarked that designers ought to have an open mind that allows for the best materials with the best performance at the best cost-benefit ratios to be selected.

The case for concrete is compelling and persuasive. Concrete has tremendous advantages that have made it a material of choice for many applications. Concrete is a cost-effective material that can be produced with a wide range of properties. Strength can be easily tuned to meet the needs of any project. One can form concrete to amazing shapes to achieve architectural impact, as demonstrated by winning projects of the ACI Excellence in Concrete Construction Awards. Design of reinforced concrete has been refined over many decades, leading to reliable and robust design protocols that can be implemented efficiently. The list goes on and on. In many applications, concrete is the obvious choice based on its performance and cost-benefit ratio.

The NIST roadmap document identified the lack of design code for FRP elements for construction. Indeed, as a university educator, I can attest to the scant attention given to FRP in the civil engineering curriculum. While we have long- established course sequences in reinforced concrete and steel design, we have no dedicated courses on the FRP system for construction. I took a course on composite materials in graduate school, but it was taught by materials science faculty who focused on aerospace applications. So, it seems to me that the hard ground work has yet to be completed to open the door for FRP structural elements to be commonly specified. The body of knowledge that might drive the use of FRP is not well established. Barriers that must be addressed include the development of college curricula, design codes, and sufficient scale and industry critical mass that can deliver FRP structural components cost effectively around the world.

In the meantime, we have our hands full at ACI with advancing the body of knowledge for concrete materials and structures. ACI draws expertise from around the world to advance concrete durability, performance, efficiency, and constructability. Our advocacy is not arbitrary, but rather is based on demonstrable advantages that make concrete the material of choice.

David A. Lange