NRMCA Staff attended the ASTM meeting held earlier this month in Orlando, FL, and submitted the following detailed report on Committees C09 on Concrete, C01 on Cement and E05 on Fire.
C09.24 Supplementary Cementitious Materials (SCM) - A new specification, ASTM C1945, for natural pozzolans to address these products separately from ASTM C618 (fly ash) has been approved. At this time the requirements for natural pozzolans are the same as for Class N in ASTM C618. New changes on natural pozzolans will be made only to ASTM C1945 and the existing Class N will be removed from ASTM C618 in the future.
The main committee ballot to remove the optional concrete shrinkage requirement in ASTM C618 was approved. The ASTM C618 note (non-mandatory) stating that fly ash is not produced from FBC ash, burning of municipal solid waste or any other refuse with coal, or the burning of industrial or municipal solid waste in incinerators has been moved to the mandatory scope section.
Committee member comments on ballot on the ASTM C1697 specification discussing the addition of limestone as a separate addition to blended SCMs were discussed. The addition of ground glass pozzolans to ASTM C1697 has been approved. The new specification for SCMs received one significant technical negative and will be revised and re-balloted. This specification will apply to alternative SCMs and to materials that fall under the scope of existing specifications like C618, C989 or C1240, but that do not comply with some specification limits.
There were discussions that the calorimetry test for SCM reactivity was more variable than the bound water test and the calorimetry test limit should be removed from the new SCM specification. Several new items were discussed in ASTM C311, including a name change and moving several tests that are not commonly used to the appendix. A task group was formed to develop a test method for measuring the water absorption of natural pozzolans.
The subcommittee continues to debate changing the ASTM C618 required fly ash LOI to “report only” but instead provide more quality control information on LOI variation that will assist concrete producers. The subcommittee has ongoing efforts to develop a specification for colloidal silica and make revisions to the glass pozzolan specification, C1866.
C09.50 Risk Management for Alkali Aggregate Reactions (AAR) - Ballot comments on the proposed revisions to ASTM C1567 to include ASTM C595 blended cements and ASTM C1697 blended SCMs were discussed. The subcommittee will develop ballots to remove the alternative containers and alternative storage requirements in ASTM C1293. Negatives relating to modifying Fig. 1 (flowchart) of ASTM C1778 were discussed. The precision and bias statement of C1567 will be updated with the recent ILS data by the subcommittee as well as the annual CCRL lab proficiency data from multiple labs.
A new ballot item will be developed to address mixing of densified silica fume in ASTM C1567. It was mentioned that lithium nitrate was mentioned in AASHTO R80 and CRD-C 662-10, and should be addressed in ASTM standards. A decision was made to ballot ASTM C441 for withdrawal. The mini concrete prism test AASHTO T 380 will be balloted as a new ASTM standard provided an exception is made to the existing ASTM, AASHTO agreement on avoiding duplication of standards. Prior to that, a round robin program on AASHTO T 380 is planned.
C09.61 Strength - The main committee ballot on changes to ASTM C31, including removal of language regarding the number of beam specimens passed. The language on leaving specimens belonging to highly retarded mixtures beyond 48 hours in the field was withdrawn. ASTM C293 will be balloted for withdrawal.
Several new items are being planned for C39, including an item on loading rate. The Fiber Reinforced Concrete Association conducted an extensive study and found that C31 consolidation procedures, including rodding, led to good consolidation and therefore FRC standards will be changed to reference C31 for consolidation. A new work item has been created to develop a new stiffness damage test to evaluate structures damaged by durability mechanisms. A new practice for end grinding of higher strength concrete specimens will be developed.
C09.66 Fluid Penetration - The subcommittee ballot to include lime water as an alternative to pore solution conditioning received one negative and the item will be reballoted. The subcommittee decided not to pursue a proposed fallen head permeability test standard due to lack of repeatability and reproduceability data. Instead, a constant head test method based on the German DIN 1048 test method was proposed by some of the members as that test is already being used by manufacturers marketing products for water permeability. A new test method to measure the gas permeability, typically in-situ, will be balloted by ASTM C09.64 Subcommittee on Nondestructive and In-Place Testing.
C09.47 Self Consolidating Concrete - This subcommittee is considering a round robin for the ASTM C1610, Static Segregation test.
E05.11 Fire Resistance - The E05.11 Subcommittee is developing revisions to ASTM E119 related to the determination of moisture content for concrete samples. The proposed revisions will adapt the methodology outlined in ASTM F2170 Standard Test Method for Determining Relative Humidity in Concrete Floor Slabs Using in situ Probes.
E05.14 External Fire Exposures - The subcommittee has developed a proposed new standard test method for determining fire propagation of exterior wall assemblies using a direct flame impingement exposure. This standard is based largely on ASTM E2707 and is intended to test the fire performance of exterior wall construction in Type V buildings. The scope of the proposed test standard is generally limited to one-and-two-family residential dwellings. The subcommittee reviewed comments received on the most recent ballot of this proposed standard and discussed revisions for reballot.
E05.23 Combustibility - A recent subcommittee ballot introduced a proposed small-scale test for combustibility as an alternative to ASTM E136. The proposed test method is intended to reduce the stringency of the test by reducing the number of thermocouples measuring temperature rise and relocating thermocouples far from the ignition source which will effectively relax the requirements for passing the test. The ballot received several persuasive negatives and the test methodology will be revised and reballotted.
Other:
A new ASTM subcommittee C09.28 on biochar has been created with Professor Lori Tunstall as chair. Biochar is carbon negative (through avoidance of carbon emissions) and, when incorporated in concrete, can help reduce the GWP of concrete.
A new subcommittee, C09.99 on Embodied Carbon and Energy Reduction, was formed with NIST’s Dr. Nick Barbosa as chair. The subcommittee will develop and maintain standards for technologies used to produce concrete having a lower embodied carbon, embodied energy or both. It will also develop specifications for direct CO2 sequestration in concrete and test methods for measuring CO2 sequestration in concrete. Currently a work item on a Test Method for Determination of CO2 in Cement and Concrete is under ASTM C01.23. ASTM C09.90 (C09 executive subcommittee) has approved the duplication of standards for specific cases where AASHTO and ASTM agree to exchange and harmonize existing standards, owned by one of the organizations and to jointly develop new standards. This will be discussed with AASHTO.
ASTM Training and OnDemand Solutions offer several eLearning standards on cement, aggregate and concrete which can be accessed here. For more information on the above reports, contact Karthik Obla at kobla@nrmca.org.
National Ready Mixed Concrete Association