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  • 1.  Type 1L Cement

    Posted 07-20-2022 01:07 PM
    In a recent concrete paving sumbittal I received, there was a letter attached which stated the following:
    "Please note all local cement suppliers are ceasing production of Type I & Type II cement to meet greenhouse gas emission limits. All cement will be Type 1L meeting ASTM C595 specifications moving forward."

    Does anyone know of any changes that we should make on our end with this upcoming change as we specify pavement (besides the cement type)?

    Heidi C. Wallace, P.E., M.ASCE
    Tulsa, OK

  • 2.  RE: Type 1L Cement

    Posted 07-21-2022 10:04 AM
    In my view use of 1L cement type ( Portland limestone cement)   required very less significant changes in mix designs. However one needs to change the safety data sheet because this cement when mix with water create a calcium hydroxide solution. It splashed in eyes or skin. So avoid contact with eyes and skin. The SDS should be consulted prior to use this cement. 

    Sukhjinder Singh CP, M.ASCE

  • 3.  RE: Type 1L Cement

    Posted 07-22-2022 10:36 AM
    Heidi, it would depend somewhat on what your pavement specifications currently contain or do not contain.  The industry seems to be moving more toward environmentally friendlier cement products across the board, and with that I see more performance specifications vs. the old school prescriptive specifications.  Have you read ASTM C595, and if so, does anything need to be adjusted in your pavement specifications to accommodate this new cement type?

    Douglas Hula P.E., M.ASCE
    Geotechnical Engineer
    Traverse City MI

  • 4.  RE: Type 1L Cement

    Posted 07-25-2022 10:05 AM
    If sulfate resistance is needed, there are other limits on the mix design and possibly other cement types required.

    Brad Watson P.E., M.ASCE
    Senior Engineer
    Freese & Nichols Inc
    Alvarado TX

  • 5.  RE: Type 1L Cement

    Posted 03-02-2023 12:07 PM

    My cousin passed this along, and I thought it might be helpful to anyone else that has questions about Type 1L cement


    Heidi C. Wallace, P.E., M.ASCE
    Tulsa, OK

  • 6.  RE: Type 1L Cement

    Posted 03-13-2023 11:26 AM

    Hello Heidi,

    We've experienced this recently as well.  On a very basic level, Type IL is noncompliant with typical specifications used by many design firms, which have called prescriptively for Type I/II for decades.  As the submittal note suggests, most major US concrete producers have switched over to exclusively IL in the last year or so.  Thoroughly researched data and ASTM-sanctioned paths to approval have been available for some time (ASTM C595), but only recently has Type IL become ubiquitous in the US.  It is great that a marginally lower-carbon product is replacing traditional concrete, but we do have a couple concerns about the transition:

    1. Research on Type IL indicates a high degree of sensitivity to particle size after grinding of the limestone.
    2. Many batch plants are swapping the cement in their mixes without additional testing.  This is a violation of the ACI requirement that test cylinders be provided for the specific mix to be used.
    3. GC's are swapping Type IL in mix submittals rather than substitution requests, which is a little sneaky if the project specifications do not list IL.  This conversation needs to be more transparent.
    4. Some data suggests possible durability issues with Type IL.  Personally, I am not convinced that this is still a serious concern, but I would be worried if the producer is unaware of the issue.

    I'm told that limestone production for Type IL is cheaper than Portland Cement, so regardless of the environmental impact, batch plants are saving money by phasing out Type I and Type II.  With all of that said, we do live under an urgent need to reduce greenhouse gas emissions, and getting greener concrete mixes on our projects should be a priority for all structural engineers.  I think engineers need to bring this up at pre-con and design assist meetings as early as possible.  General Contractors need to push their suppliers to develop mix-specific test data, and understand that they've bid on a set of project specifications and have a responsibility to address supply chain and cost issues in a timely and transparent manner.  As with any eleventh-hour substitution request, reviewing engineers should understand risks and benefits to the project before accepting--or outright rejecting--a switch to Type IL.  In the meantime, we need to revisit our specifications post haste.  Designers are already behind the curve on this.

    Christian Parker P.E., M.ASCE
    Structural Project Engineer
    Washington DC

  • 7.  RE: Type 1L Cement

    Posted 03-14-2023 05:20 PM

    I am curious as to how these changes impact those large projects that are 3-5 years in the making with several years to go. The EORs probably have this in mind and are prepared to address.  

    When required, I will do the deep dive into the research for the next small concrete slab I have to design. 

    Thank you for the posting. 

    James Williams P.E., M.ASCE
    POA&M Structural Engineering, PLC
    Yorktown, VA

  • 8.  RE: Type 1L Cement

    Posted 03-19-2023 08:18 PM

    This feels like a major change. Who 'signed' off on the change and were they sufficiently informed as to the known unknowns and the unknown unknowns? This may sound trite but moving from a formulation that's tried and true to a new formulation poses an immense risk if the approvers got it wrong.

    Mitch Winkler P.E., M.ASCE
    Houston, TX