NRMCA Engineering Staff Files Report on ACI Fall 2024 Convention

The American Concrete Institute's Fall Convention was held from November 2 - 6 in Philadelphia; the following summaries of committee activity involved NRMCA Engineering Staff representation.

122 – Energy Efficiency of Concrete and Masonry Systems – With the publishing of ACI 122.2 and 122.3 Thermal Properties of Concrete and Masonry for Residential and Commercial Buildings, the ACI 122R-14 Guide will be transitioned to a historical document. The committee also hosted a full session at the convention titled, Chill Out! Reduce Operational Energy and Carbon with Thermal Mass, featuring presentations on Threats to Mass Walls in the Energy Codes, The Benefits of Using ACI 122.1 for Compliance with Thermal Bridging Requirements and Reducing Energy Use with Mass Walls. Darryl Dixon maintains representation in ACI 122.

132 – Responsibilities in Concrete Construction – The committee has addressed comments from Technical Activities Committee (TAC) to finalize its primary document on responsibilities in concrete construction. Some considerations by the committee include developing a standard on responsibility in concrete construction; rewriting the section on responsibility of forensic engineers and developing a section of the guide to discuss responsibility of special inspectors. The committee sponsored a panel discussion that reviewed its newly published Responsibility in Concrete Rehabilitation Construction Guide. Colin Lobo maintains representation on ACI 132.

201 – Durability – The committee continues to work on incremental changes to its Guide to Durable Concrete. Revisions to the chapter on freezing and thawing were discussed. Other chapters on mass transport, chemical attack, aggregate reactions and corrosion are being revised. Exposure classes and applicable requirements for concrete requirements for all of these categories are being developed. A chapter on aggregate reactions will address ASR management of structures. Karthik Obla maintains representation in ACI 201.

211 – Mixture Proportioning – The committee continues to work on several draft documents: Assessing Combined Aggregate Gradings Guide, Tech Note on three-point curves for mixture evaluation, report on aggregate packing models for optimizing mixtures and the Guide to Troubleshooting Concrete Mixture Issues as Influenced by Constitutive Materials and Jobsite Conditions. The committee discussed updating the water demand table based on a producer survey. The 211 survey indicated that no changes were needed to the coarse aggregate proportions (b/bo table) in the mixture proportioning guide. Karthik Obla maintains representation in ACI 211.

214 – Evaluation of Results of Tests – The committee balloted changes to two chapters of the Guide to Evaluation of Strength Test Results of Concrete. The committee will take up the following in the future: addressing outliers in core tests; developing tech notes on establishing required averages for specified properties and using easy statistical concepts in mixture development. Karthik Obla is the committee chair.

216 – Fire Resistance and Fire Protection of Structures – Revisions to ACI 216.1, Code Requirements for Determining Fire Resistance of Concrete and Masonry Construction Assemblies, are currently in the Comment Resolution Phase. A Rational Design Guide document is also being developed in parallel. A task group of the committee continues to develop a Tech Note regarding the equivalence of portland limestone cement to portland cement in terms of fire resistance. Additional revisions to ACI 219.1 based on revisions to ASTM 119 Table X3.1 published in June 2024 may be incorporated during the Public Comment phase. Shamim Rashid-Sumar maintains representation on ACI 216.

240 – Natural Pozzolans – The committee is working on a Tech Note titled What is a Pozzolan and reports on Calcined Clay and Ground Glass Pozzolan. The committee is also updating the existing natural pozzolan document ACI 232.1. Karthik Obla maintains representation on ACI 240.

301 – Specifications for Structural Concrete – The committee continues making changes to several sections of the specification, submittal requirements for sustainability, requirements for alkali aggregate reactions, post tenstioned systems, lightweight concrete, handling placing and constructing, architectural concrete and shrinkage-compensating concrete. ACI 301 will also incorporate approved revisions to ACI 318 that impact the specification. Colin Lobo maintains representation on ACI 301.

318 – Building Code for Structural Concrete – The committee received close to 800 public comments, developed responses and balloted these responses through the committee. This generated a large number of issues to address on possible changes to the Code at its last meeting. The committee finalized its responses to public comments. There were some resulting minor changes to the Code, but most of the issues raised by public comments were collected to be addressed as new business in the next code cycle. The committee has completed its work for this cycle and will be disbanded when the Code is published in January.

ACI 318 has some revisions to the chapters on requirements for concrete and durability (19) and construction documents (26). A new Appendix N addresses sustainability. ACI 318-25 is scheduled to be published in January with the goal that it can be referenced by the International Building Code.ACI is selecting a chairman for Committee 318, following which subcommittee chairs and committee members will be selected for the next cycle that goes for a period of six years. Colin Lobo maintained representation on Subcommittees A (concrete materials) and N (sustainability) and on the 318 main committee.

323 – Low Carbon Concrete Code – The ACI 323 Low-carbon Concrete Code Committee wrapped up its work on the Low-Carbon Concrete - Code Requirements and Commentary. The Code is now available for download and new committee members will be selected for the next version. Tiffany Reed-Villarreal maintains representation on ACI 323.

325 – Concrete Pavements – The committee currently has four documents under development or revision. The committee is rewriting ACI 325.12R-02 (Reapproved 2019): Guide for Design of Jointed Concrete Pavements for Streets and Local Roads led by Killingsworth. Revisions to this document have been completed and TAC has returned comments and the committee is balloting the response to those comments. The updated guide should be published in 2025.

The committee is developing ACI 325.YR Report on Precast Concrete Pavements - State of the Practice which is being formatted for committee review. Work is also underway to update ACI 325.ZR: Design and Construction of Continuously Reinforced Concrete Pavements. This work will continue over the next year and will be re-balloted. ACI 325.13R-06: Concrete Overlays for Pavement Rehabilitation has also been updated, balloted and submitted to staff for TAC review. Brian Killingsworth maintains representation on ACI 325 on concrete pavements. 

327 – Roller-Compacted Concrete Pavements – The committee continues to work on ACI SPEC-327.Y – Construction of Roller-Compacted Concrete Pavements – Specification. The subcommittee working on the specification document has made a lot of progress and is planning to have something to share with the main committee for comments by the end of 2024. The main committee is also rewriting ACI PRC-327 – Guide to Roller-Compacted Concrete Pavements led by Halsted. The Guide document has been completed and is now at TAC with a scheduled publication date by the end of 2024.

A mini session titled Revolutionizing RCC Pavements: Design Parameters, Construction Techniques, and Sustainable Advantages was presented before the recent committee meeting and attracted approximately 45 participants. Halsted will ensure that considerations for sustainable streets and local roads will be included in all documents. Greg Halsted maintains representation on ACI 327 as chair.

329 – Performance Criteria for Ready Mixed Concrete – The committee did not meet. It is working on developing a guide to writing a performance-based specification and will ballot proposed chapters that cover Section 1 on General Requirements and Section 2 on Products, including performance requirements for concrete mixtures. The guide is using the MasterSpec 033000 format with commentary as advisory information for specifiers. Karthik Obla and Colin Lobo maintain representation on ACI 329.

330 – Parking Lots – The ACI 330.1 Specification has been successfully processed through all ACI review procedures. The committee reviewed the work from ACI 117 for tolerances which is referenced in the 330 specification. Discussion was had on pavement over expansion and the committee determined to address in the revision of the ACI 330.2R Industrial Guide.

Revision of 330.2R Guide for the Design and Construction of Concrete Site Paving for Industrial and Trucking Facilities has begun. Amanda Hult maintains representation in ACI 330.332 – Residential Concrete. The committee continues to work on revisions to ACI 332, Code Requirements for Residential Concrete, and resolve negatives from its most recent ballot. The current proposed revisions include incorporation of NRMCA 100-23 provisions into ACI 332. In addition, the committee discussed updates from ITG12 on 3D Printed (Additive Concrete) Houses and wire reinforcement in residential concrete work.  Julian Mills-Beale maintains membership on ACI 332.

522 – Pervious Concrete – The 522 committee discussed acceptance criteria discrepancy between ASTM C1688 and ACI SPEC-522.1. Committee voted to revise the specification and distribute for vote. The transition of the Pervious Contractor Certification from NRMCA to ACI was presented to the committee. Members provided ideas on how the ACI version of the certification/certificate would look once ACI took over. The committee will continue to work with NRMCA and ACI on the transition. Amanda Hult maintains representation in ACI 522.

551 – Tilt-Up Concrete Construction – ACI 551 Committee is looking for guidance on energy efficiency and sustainability in concrete tilt-up construction. Build With Strength will collaborate to get the ACI 551 committee educated on the benefits of concrete sustainability and energy efficiency. The education session will be planned for ACI 2025 in Toronto. Darryl Dixon maintains representation in ACI 551.

555 – Recycled Materials – The committee is working on a Tech Note on processing returned concrete for use as aggregate. It also discussed developing content on managing returned fresh concrete. Karthik Obla maintains representation on ACI 555.

560 – ICF Buildings – The committee continued its update on ACI PRC-560-22 Insulating Concrete Form Design and Construction after discussions on the negative public comments received. The update is earmarked to be completed before the next ACI Spring Convention in Toronto. A mini session was hosted titled NRMCA 100: Introduction and Overview.

Furthermore, the committee proposed strategies for developing a concrete consolidation standard for the ICF industry while updates were provided on the NFPA 285 testing program. Potential synergistic efforts between the committee and the National Association of Home Builders (NAHB) was also discussed at the meeting. Julian Mills-Beale and Shamim Rashid-Sumar maintain representation on ACI 560.

Concrete Research Council (CRC) – The Research Council of the ACI Foundation annually funds research programs. The ACI Foundation is changing the process of funding research in the future. Project ideas will be developed by a steering group and request for proposals for topics of primary interest to ACI committees will be solicited.

Four projects under this concept are being evaluated currently for funding. Reports of previous and ongoing projects are available on the website of the ACI Foundation. Colin Lobo maintains representation on ACI CRC.

Other ACI Convention News – NRMCA staff delivered several presentations at this convention:

• Karthik Obla presented on Overdesign of Concrete Mixtures at a mini-session.
• Brian Killingsworth presented Sustainable Solutions: Low Carbon Pavement Strategies and Successes as part of a session titled Demonstrating Low Carbon Concrete In Pavement Applications.
• Brian Killingsworth presented The Concrete Industry’s Perspective on Public Procurement of Low Carbon Construction Materials as part of a session titled Impact of Buy Clean and Low-Carbon Policies on the Sustainability of Concrete.
• Julian Mills-Beale presented a mini-session on Introduction and Overview of NRMCA 100.
• Tiffany Reed-Villarreal presented on Sustainable Concrete in Codes, Standards, and Policy as part of a Hot Topic Session: Here Come EPDs – Are You Prepared?
• Shamim Rashid-Sumar presented on Model Codes: Proposals for the 2027- I-Codes as part of a session titled Destiny of Concrete – Rules and Regulations.

Click here to access contact information for any of the NRMCA staff listed above should you need more information.