NRMCA Engineering Staff Files Detailed Summary from Key ASTM Committee Meetings

Following is a summary of activity which took place at the ASTM meeting in Philadelphia in June on Committees C09 on Concrete, C01 on Cement and E05 on Fire attended by NRMCA staff.

C09.20 Aggregates - A revision was approved to specification C33 on normal-weight aggregates for concrete, to simplify the limits for deleterious materials for coarse aggregate by establishing durability class designations based on potential exposure of concrete and eliminating that based on U.S. weathering zones. The committee will consider as new business if soundness requirements should be stated for aggregates used in wetting and drying applications and a suggestion to use the micro-Deval method as an alternate to soundness test (C88).

ASTM C127 on Measuring Characteristics of Coarse Aggregate expired due to the date it was last revised and was reinstated. Revisions to C142 on Clay Lumps and Friable Particles are being developed. A request was made to revise some of the requirements of the specification for mineral fillers, ASTM C1797, to accommodate some new manufactured mineral fillers. NSSGA noted the collection of blind aggregate samples that would be tested for the presence of pyrrhotite mineral by several research groups through a funded effort. Hadi Rashidi at NSSGA can be contacted for more information.

C09.23 Chemical Admixtures - The subcommittee is working on specifications for anti-washout, shrinkage reducing, durability enhancing and ASR control admixtures in various stages of development. Revisions to ASTM C494 and C260 will permit the qualification of admixtures using ASTM C595 Type IL (portland limestone cement) as an alternate. A revision to C494 proposes to eliminate the compressive strength requirements at one year for most admixture types. The subcommittee will attempt to define mid-range water reducing admixtures in C494 and address the appropriate use of Type S for special performance, as there is concern that some products are being qualified not consistent with the intent of this type.

C09.24 Supplementary Cementitious Materials (SCM) - The subcommittee has revised ASTM C311 to allow the use of Type IL cement for strength activity index of coal ash and natural pozzolans. A new specification for natural pozzolans to address these products separately from ASTM C618 has been approved. At this time the requirements for natural pozzolans are the same as for Class N in ASTM C618 and changes will be made to address these types of materials.

The subcommittee has ongoing efforts to develop a specification for colloidal silica and make revisions to the glass pozzolan specification, C1866. The subcommittee ballot to change ASTM C618 required LOI to “report only” drew negatives which were discussed. The new specification for SCMs received several negatives 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.

FHWA is completing a tech note on R3 SCM reactivity tests covered in ASTM C1897. These tests have value in product development, R&D, internal QC and for differentiating between inert and reactive materials. It was generally felt that the bound water test was more robust than the calorimetry. The PCR for coal ash has been completed and an Industry wide EPD is being developed. EPDs for harvested coal ash will be developed by individual companies. EPRI has developed an LCA of harvested ash. The American Coal Ash Association reported that about 3M tons of harvested ash was used in the U.S. last year.

C09.40 Ready Mixed Concrete - Revisions approved to ASTM C94, Specification for Ready Mixed Concrete to clarify a requirement to maintain availability of mix designs at the plant and to include the quantity of jobsite water addition permitted at the request of the purchaser. Other revisions in progress include revisions to reporting time and revolution limits to discharge on the delivery ticket; to remove Option C that specifies minimum cement content; to include performance properties other than strength and to correct some of the other information in the ordering section; to clarify curing of test specimens and to address retesting concrete that failed to meet slump and/or air content requirements before rejecting a load.

ASTM C1798 was revised to use the term “producer” instead of “manufacturer” in the standard.

C09.50 Risk Management for Alkali Aggregate Reactions (AAR) - A revision has been made to permit the use of Type IL cement in ASTM C1260, ASTM C1778 and ASTM C1293. Similar changes are being proposed for ASTM C1567. Observations in inter-lab programs suggest that using Type IL cement in mortar bar tests seemed to reduce ASR expansions; the committee will propose some cautions on the use of these data for projects mix qualification. Revisions to ASTM C1567 will address the evaluation of ASTM C595 cements and ASTM C1697 blended SCMs mitigating ASR.

The subcommittee will develop ballots to remove the alternative containers and alternative storage requirements in ASTM C1293. Negatives related to removing Fig. 1 and 3 from ASTM C1778 were discussed. A new ballot will address the use of ASTM C441 for evaluation of the effectiveness of SCMs in ASTM C1778. The subcommittee supported the development of a more concise ASR specification based on ASTM C1778 (a guide) and that can be referenced in ACI Codes and specifications.

C09.51 Sulfate Resistance of Concrete - A new subcommittee has been established to harmonize how sulfate resistance is addressed in ASTM standards and to develop a guide or practice to address requirements to minimize sulfate resistance of concrete, similar to the Guide for Alkali Aggregate Reactions, ASTM C1778.

C09.60 Fresh Concrete Tests - Minor revisions were approved to C138 (density) to check viberator frequency and to C173 (air by volumetric method) on the procedure for taking readings. Revisions are in the works for ASTM C172 (sampling) to state uniform requirements for wet sieving concrete with larger aggregate and to C173 (air by volumetric method) to clarify the calibration procedure. The subcommittee is developing standards for the sequential air meter (SAM) and the measurement of water content of fresh concrete using a high-power oven at the jobsite (referred to as the Phoenix).

C09.61 Strength - Revisions were approved to the practice for making and curing strength specimens, ASTM C31, to clarify some of the procedures and terminology used. A revision to C39 was approved to include precision information of tests of 4 x 8-inch specimens made in field conditions. Revisions are being developed for standards for capping - C617 to eliminate the method to cap fresh concrete with neat cement paste and C1231 to permit unbonded caps with higher durometer hardness. The subcommittee discussed several issues that will be proposed as revisions to C31.

C09.66 Fluid Penetration - The subcommittee has revised ASTM C1876 to add a step of rinsing the specimens conditioned in simulated pore solution under tap water before measuring bulk resistivity. This step originally proposed by NRMCA considerably improved the precision and improved the stability of the measurement. A new ballot will propose permitting conditioning specimens in lime water.

Several changes are being planned for ASTM C642. A new test method to measure the gas permeability, typically in-situ, has been developed and will be balloted by ASTM C09.64 subcommittee on Nondestructive and In-Place Testing.

C01.10 Cement - Some revisions approved to cement standards: removal of Type II(MH) and Type IV cements in C150, with the option for the purchaser to request heat of hydration information; removal of special property heat of hydration MH and LH in C595 (heat of hydration at 3 days determined by isothermal calorimetry, ASTM C1702, at the request of the purchaser); permit interground limestone from manufactured sources and to change the requirement for limestone to accommodate dolomitic limestones (higher MgO content).

Items proposed for ballot or being discussed: Increase the LOI limit for blended cements to accommodate the use of natural pozzolans; clarify reporting of alkali content of components and of the finished product for blended cement (to support the calculation of concrete alkali loading); consider reporting oxide composition of clinker in blended cements; change the qualification of Type IL cements for sulfate resistance (to use C452 instead of C1012); change the limits for MgO in blended cements to the basis of the clinker; permit the use of two SCMs in addition to limestone in Type IT (ternary) blended cements; proposed a new type of blended cement (tentatively Type IC) that will have a minimum limit on the clinker content; standardize the various terms used for “mill test reports” and to revise the definition “limestone” for cement standards.

There are initiatives to develop specifications for geopolymer and non-hydraulic cements in Committee C01.

E05.11 Fire Resistance - NRMCA presented the results of its most recent ballot to revise ASTM E119 Standard Test Methods for Fire Tests of Building Construction and Materials. The ballot was successful and the published revisions provide clarifications to ASTM E119 Table X3.1 Guide for Determination of Restrained and Unrestrained Conditions of Construction. The E05.11 Subcommittee is also 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.

Symposium - Committee C09 organized a symposium on June 9: Workshop on Next Generation Cements and SCMs: Towards Specification that was attended by more than 150 people. Representatives from several evolving cementitious materials presented on the concepts of their products, impact to carbon reduction of concrete and progress to scaling for industry use: Terra CO2, Carbon Upcycling Technologies, Fortera Corporation, Brimstone, Sublime Systems, CarbonBuilt, Inc., Carbon Limit Co were among the companies.

Other presentations covered some challenges with evaluating SCMs for use in concrete; the need for performance specifications for cements and SCMs; role of demonstration projects toward achieving acceptance of innovative materials and ending with a panel discussion discussing forward progress.

NRMCA’s Karthik Obla presented on Innovation in the Concrete Industry by outlining some of the innovations accepted and used by the industry.

Other - ASTM’s highest award, the Award of Merit was presented to Chris Slate with NRMCA Producer member Alamo Concrete and to Mark Niemuth with NRMCA Producer member Cemex.

ASTM Training and OnDemand Solutions offer several eLearning standards on cement, aggregate and concrete which can be accessed here. NRMCA staff involved in these summaries are Colin Lobo, Karthik Obla and Shamim Rashid-Sumar.