NRMCA Attends ACI Spring 2012 Convention, Updates Committee Action

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The ACI Spring Convention in Dallas was held during the week of March 18. Below is an update of some of activities that involved NRMCA representation.

130 – Sustainability Committee: NRMCA’s Lionel Lemay is NRMCA’s representative on ACI 130 Committee on Sustainability. The committee continues to march slowly toward an in-depth document on the sustainability of concrete. Lemay has written the chapters on materials, concrete proportioning and production and will have all negatives resolved by mid-April. The chapters reference several NRMCA programs to meet sustainability objectives, including Green-Star and Sustainable Concrete Plant Certification. Lemay is also working on chapters related to sustainability design tools, rating systems, codes and standards. The document is expected to be finalized by the end of 2012.

132 – Responsibilities in Concrete Construction: This is a newly formed technical committee from the previous board committee. The committee is soliciting members to ensure a balanced distribution of stakeholder representation. It has completed a comprehensive document that discusses the individual and joint responsibilities of stakeholders in concrete construction that is in the ACI review process.

201 – Durability: The 201.2R Guide to Durable Concrete is being revised. Revisions to the chapter on sulfate attack were made. Sulfate attack can be due to chemical attack. Physical salt attack due to sulfates was also discussed but the mechanism and mitigation methods are different and are discussed in a different chapter. Physical salt attack resembles surface scaling due to freezing and thawing. Several papers were presented at a couple of technical sessions on physical salt attack.

211 – Mixture Proportioning: The document "Standard Practice for Selecting Proportions for Normal, Heavyweight, and Mass Concrete" is being re-balloted. TAC suggestions on the new chapter on concrete mixture submittals are being addressed by the committee. This chapter includes examples of prescriptive and performance submittals. Mixture proportioning for no slump concrete will be revised substantially. A new chapter on mixture evaluation has been finalized. New task groups are working on mixture proportioning for pumping and mixture proportioning with limestone fillers.

214 – Strength Tests: This committee is looking for project compressive strength test data to update the table showing the standards of concrete control for both testing variability as well as batch to batch variability.

232 – Fly Ash and Natural Pozzolans: ACI 232.2R, Use of Fly Ash in Concrete, has now been finalized after multiple ballots and will be sent for ACI TAC review this spring. The committee is developing a report on high volume fly ash (HVFA) concrete. ACI 232.1R, Use of Natural Pozzolans in Concrete, has been finalized and should be published in the next ACI Manual of Concrete Practice. Tom Adams with ACAA mentioned that S.1751, the "Coal Residuals Reuse and Management Act," has been introduced in the Senate. This is related to a similar resolution HR.2272 that has already passed the U.S. House of Representatives. The legislation will prohibit the EPA from regulating CCR as a hazardous waste and establishes minimum federal requirements for the management and disposal of coal combustion residuals that will ensure safety and the protection of human health and the environment. The federal criteria will be administered by states through enforceable permits and by EPA if a state fails to meet the federal baseline.

In another development, environmental groups have sent a notice of intent of legal action against the EPA and two fly ash marketers have taken similar action. The ACI Fall 2012 convention will feature two technical sessions on Natural Pozzolans. The ACI Fall 2013 convention is likely to feature sessions on Green Binders.

301 – Specifications for Structural Concrete: ACI 301 balloted sections on concrete materials, section 4, Construction, section 5, lightweight concrete, shrinkage compensating concrete and mass concrete, among others as it works toward the next revision of the specification. The ballot on section 4 proposed several revisions to improve the specification and the committee is working through several comments from the ballot. Also in the works will be proposals for including criteria for alkali silica reactivity in the next balloting process. ACI 301 is working toward completing its revised specification by Fall 2013. Colin Lobo maintains representation on ACI 301 as do several members of the NRMCA RES Committee.

318 – Building Code for Structural Concrete: Lobo maintains representation on ACI 318. The primary activity is the development of a reorganized member-based code. The chapters on materials are essentially completed and commentary relevant to these code sections is being added. A significant change was approved by Committee 318 that will remove all the details of proportioning concrete mixtures from the Code and refer this process to ACI 301. Another significant action is the development of a new chapter on what needs to be included in construction documents. This is a new chapter in the Code that will provide a list of design, materials and construction items that need to be addressed in project specifications and drawings, among other documents. ACI 318 is attempting to complete its work to be referenced in the 2015 International Building Code.

325 – Concrete Pavements: NRMCA’s Brian Killingsworth will maintain representation on ACI 325 on Concrete Pavements. The committee currently has five documents under development or revision. The report ACI 325.9R Guide for Construction of Concrete Pavements is currently under complete revision and near final balloting. The committee also decided to work toward re-approval of ACI 325.12R-02: Guide for Design of Jointed Concrete Pavements for Streets and Local Roads after reissuing with dual units, correction of the design thickness tables, and addressing a few editorial changes. Killingsworth will lead this effort for the subcommittee. A complete revision with updated thickness tables and other technical revisions will begin after the document is reapproved.

The committee is developing ACI 325.XR Report on Precast Concrete Pavements - State of the Practice which is based upon work completed by Tayabji for SHRP2. Eventually this document will become a design and construction report for precast and prestressed pavements. The committee is also developing ACI 325.YR Proportioning, Quality Control and Evaluation of Concrete Pavement Strength Relationships. The document is about 90% complete and is being prepared for balloting by the Fall 2012 convention. A revision is underway of 325.11R Accelerated Techniques for Concrete Paving. Work is in the initial stages but progress has been good. The effort will harmonize with the proportioning document. Killingsworth will ensure that considerations for streets and local roads will be included in the revised document.

327 – Roller-Compacted Concrete Pavements: Killingsworth will maintain representation on this committee. Current activities include resolving negative votes on the report ACI 327.XR Report on Roller-Compacted Concrete Pavements. The committee will also begin development of an RCC specification for materials and construction to supplement report 327.XR. The committee also sponsored the session entitled Symposium on Integrated Cement Based Pavement Solutions, Part 3: Sustainable Aspects of Soil Cement Pavements during the spring convention which was well attended. 329 – Performance Criteria for Materials for Ready Mixed Concrete

The committee has completed revisions to the ITG-8 report and will submit this to TAC for approval as a document of Committee 329. The committee has established task groups for public relations on performance specifications by the development of a standard presentation that could be used to various groups. Another task group was established to develop and recommend performance-based alternatives to ACI Committees 301 on specification and 318 on the Building Code. The committee is planning a technical session in Fall 2013 on Case Studies of Performance Based Projects. A draft performance specification in the CSI MasterFormat was provided to the committee from NRMCA’s P2P efforts.

330 – Design and Construction of Concrete Parking Lots: The 330 Committee has been working on creating an additional document that addresses concrete parking lots for industrial and trucking facilities ("330 X"). Several breakout meetings discussed comments on the design chapter of this document as the other chapters have been completed. The negative comments were discussed and voted on in the 330 Committee meeting. Also, negative comments related to the updated 330.1 Specification for Unreinforced Concrete Parking Lots were also resolved.

332 – Residential: Lemay is NRMCA’s representative on the ACI 332 Committee on Residential Concrete Work. The committee finalized changes to ACI 332-13 Residential Code for Residential Concrete. The committee agreed on a change in the concrete requirements section to lower the minimum strength requirements for residential concrete since the current requirements appear to be too high for residential applications. The next step is to send the document for public comment with final approval in time for the next version of the International Residential Code. 522 – Pervious Concrete.

The committee has completed the review of the specification ACI 522.1 through TAC and the specification will be posted for public comment later in summer. This will permit the revised specification to be published later this year if all comments are addressed. An effort is underway to start balloting revisions to the guide document, ACI 522R, with a goal of publishing the next version in 2014. The committee is also working on new standard details for pervious concrete pavements. Matt Offenberg steps down as committee chair after a long term of service; he was recognized during the ACI Awards session. Charles Weiss with the US Army Corps of Engineers will assume the role of chair of ACI 522. (Excerpts from Matt Offenberg’s blog - http://www.perviousblog.com/)

555 – Recycled Materials: The document "Removal and Reuse of Hardened Concrete" is undergoing revisions and will include discussions on crushed returned concrete aggregates based on research work conducted at the NRMCA Research Laboratory.

560 – Insulating Concrete Forms: NRMCA’s Lemay represents the ready mixed concrete industry before ACI 560 Committee on Insulating Concrete Forms. The committee has been plagued with slow progress with regard to developing a design and construction guide for ICFs. The first few chapters are now beginning the balloting process which could help accelerate its development.

Session on Total Water Control: Karthik Obla of NRMCA presented Mixing Water Control during a session sponsored by ACI 121 Quality Assurance Systems of Concrete Committee. Obla quantified the impact of variation of water and air content on variability of strength tests. Reduced variability of compressive strength is achieved by, among other things, better control and reduced variation in water content. Various factors and methods to reduce the variability of mixing water content were addressed by Obla and the other speakers.

For more information, contact Colin Lobo at clobo@nrmca.org, Lionel Lemay at llemay@nrmca.org,  Karthik Obla at kobla@nrmca.org or Brian Killingsworth at bkillingsworth@nrmca.org.