NRMCA Attends ACI Spring 2022 Convention; Files Report on Key Ready Mix Developments

The American Concrete Institute's convention was held in person after a 2-year absence from March 26 - 30 in Orlando, FL. The following is a summary of committee activity involving NRMCA Staff representation:

132 – Responsibilities in Concrete Construction – The committee completed a Technical Note (TN) on responsibilities associated with acceptance testing of concrete specific to care of test specimens at the jobsite with responsibilities for curing at the jobsite. The TN will be published this summer. A new guide to responsibilities in concrete repair and rehabilitation is going through the review process. The committee has begun the process of revising its guide to responsibilities in concrete construction, ACI 132R. The committee will sponsor a Hot Topic session at the next convention related to responsibilities for low carbon concrete. The committee received an update on the CTAC program managed by the Colorado Ready mixed Concrete Association that records observations of testing at the jobsite. Colin Lobo maintains representation on ACI 132.

201 – Durability – The committee is revising the guide to durable concrete (201.2R). The committee reviewed responses to ballots and approved four revised chapters during its meeting. Karthik Obla maintains representation in ACI 201.

216 – Fire Resistance and Fire Protection of Structures – The ACI 216 Committee continues to finalize the revised edition of ACI 216.1, Code Requirements for Determining Fire Resistance of Concrete and Masonry Construction Assemblies. This updated edition of the standard will include a new chapter on loads in fire addressing strength reduction factors, load factors and load combinations. Additionally, the committee is finalizing the new rational design guide on determining fire resistance. The document will provide guidelines for determining fire resistance through analytical methods in addition to the existing prescriptive methods. The technical committee has also developed a new chapter on post-fire assessment and repair in ACI 562, Code Requirements for Assessment, Repair, and Rehabilitation of Existing Concrete Structures. Shamim Rashid-Sumar maintains representation on ACI 216.

232 – Fly Ash – A Tech Note on harvested ash has been published. The committee discussed the development of a new document on the use of crushed bottom ash and harvested fly ash as supplementary cementitious material for concrete. There was an update on the various research projects addressing fly ash supply. Karthik Obla maintains representation on ACI 232.

301 – Specifications for Structural Concrete – The subcommittee responsible for Section 4 on Concrete Mixtures balloted a significant reorganization of the section to consolidate and categorize submittals that proposed other revisions. The section will be reballoted considering the comments and propose other revisions identified during the meeting. Subcommittee responsible for post tensioned systems in Section 9 will separate provisions for bonded and unbonded PT construction. The committee discussed revisions being proposed by subcommittees to other sections of the specification, including construction with expansive cements and defining types of concrete that would require thermal control plans based on section dimension or mixture composition. This will be an attempt to redefine “mass concrete” in the specification. The committee is working toward a revision to the ACI 301 specification to be published after 2025. Colin Lobo maintains representation on ACI 301.

318 – Building Code for Structural Concrete – ACI Subcommittee A on concrete materials is progressing on several code change proposals. Approved items at this meeting include provisions to prevent corrosion of aluminum embedments and to permit two 4 by 8 in. specimens for a strength test (instead of 3). Other change proposals in progress include addressing criteria for field cured specimens for post tensioning and formwork, including additional curing requirements for hot and cold weather concreting to include an option to terminate curing based on age or in-place strength; removing the limits on SCMs for concrete exposed to deicer scaling; revising chloride exposure class to include air-borne chlorides for structures close to the ocean; the acceptance process for density of lightweight concrete and addressing sampling at the point of placement at the option of the designer to include a performance requirement based on ASTM C1202 instead of a limit on w/cm and several other changes.

Subcommittee N on Sustainability balloted a new appendix on sustainability at the main committee; it received several comments that will be resolved to ballot revised content. The appendix is not mandatory but can be used by the designer if there is a sustainability goal on a project. The appendix includes structural system sustainability, concrete materials for reduced environmental impact, and system resilience. ACI 318 is working toward publishing the revised Code in 2025.

Colin Lobo maintains representation on Subcommittees A and N and on the main 318 Committee.

325 – Concrete Pavements – The committee currently has four documents under development or revision. The committee is rewriting ACI 325.12R-02 (Reapproved 2014): Guide for Design of Jointed Concrete Pavements for Streets and Local Roads led by Brian Killingsworth. Revisions to this document have been completed and balloted negatives are being resolved. The committee is developing ACI 325.YR Report on Precast Concrete Pavements - State of the Practice which is based upon work completed by Tayabji for the FHWA. 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. ACI 325.13R-06: Concrete Overlays for Pavement Rehabilitation has also been updated and will be balloted this summer. Killingsworth will ensure that considerations for streets and local roads will be included in all documents. Brian Killingsworth maintains representation on ACI 325 on concrete pavements.

329 – Performance Criteria for Ready Mixed Concrete – ACI 329 is working on developing a guide to writing a performance specification. The committee completed a ballot adding to a chapter that briefly describes various test methods and requirements for concrete. It will reballot Section 1 of the specification based on comments from a previous ballot and complete the chapter on test method descriptions before the next meeting. Karthik Obla and Colin Lobo maintain representation on ACI 329.

330 – Parking Lots – The ACI 330 Committee is awaiting TAC comments on the ACI specification document-330.1. The committee will likely hold a virtual meeting prior to the fall meeting to address TAC comments. The ACI PCR-330.2 Industrial Guide is the next document in need of a revision. Initial discussion began on items that were identified as topics requiring discussion and revisions. The committee is submitting to host mini-session presentations at the Fall meeting. Amanda Hult maintains representation in ACI 330.

332 – Residential Concrete – Extensive discussion occurred surrounding the fate of PCA 100, Prescriptive Design of Exterior Concrete Walls for One- and Two-Family Dwellings, in both the long and short term. The above grade wall subcommittee intends to eventually bring the PCA 100 content into the ACI standards and guidelines. There is support for NRMCA taking on PCA 100 in the short to medium term. Mike Weber will replace Jamie Farny as chair of 332. Scott Campbell maintains membership on ACI 332.

522 – Pervious Concrete – The ACI 522 Committee addressed the remaining TAC comments on the 522R document. Volunteers were solicited for the next student competition in the fall, which is for pervious concrete. The committee is submitting to host mini-session presentations at the fall meeting. Amanda Hult maintains representation in ACI 522.

560 – ICF Buildings – A technical mini-session titled Fire Testing of ICF Walls was presented during the committee meeting by Shamim Rashid-Sumar. The committee’s guide document update of example problems has been finalized and submitted for publication. An update was presented on the two-story limitation of ICF walls and it was confirmed this provision has been removed from ACI 318. The revision will be effective in the 2024 edition of the standard. An additional update was provided on the status of PCA 100. Craig McKee takes over as chair of 560 from Robert Sculthorpe who served as chair for several years. Scott Campbell and Shamim Rashid-Sumar maintain representation on ACI 560.

Concrete Research Council (CRC) – The Research Council of the ACI Foundation solicited research proposals for consideration. Research proposals should support the activity of ACI committees and should indicate support from affected committees. For this cycle, funding was available to support 10 proposals. Of the 20 proposals received, the process of selection recommended funding six proposals in the materials area and four in the structures area. The funded projects will be announced soon. Each proposal receives funding of $50,000 from CRC. Colin Lobo maintains representation on ACI CRC.

Other: Charles Nmai with Master Builders Solutions was elected as president of ACI for a one-year term. Several individual awards were presented at this convention. Of note, honorary membership, one of the highest ACI recognitions, was awarded to Bev Garnant, executive director of the American Society of Concrete Contractors (ASCC). ACI announced the launch of a Center for Excellence for Carbon Neutral Concrete to be headed up by Andrea Schokker; details will be announced soon at www.neuconcrete.org.