APPENDIX B

Detailed Survey Responses

Table B1. States responding to survey questionnaire.*

^*Names and contact information of responding persons are not included in the report.

Table B2. Q2: Does your DOT specification allow the use of SCMs in concrete?

Responded: 43

Table B3. Q3: In which concrete applications does your specification allow the use of SCMs?

Responded: 40

Table B4. Q4: Does your DOT specify SCMs in concrete to satisfy the conditions below?

Responded: 41

Comments by respondents who marked “none of the above” or “other”:

• MA – We require SCMs in all mixes.

• VA – All concretes except patches

• DE – ASR mitigation

• TX – ASR mitigation

• PA – Also used for potential ASR mitigation

• IL – SCM use is optional, but they are often used, most commonly to mitigate for ASR and thermal control of mass pours (not a specified requirement, more of an accepted fact).

• VT – ASR mitigation

• NC – For use with high alkali cements (>= 0.6%)

• RI – ASR mitigation

• CT – We have performance specifications. Concrete producers can use SCMs to meet criteria.

• AZ – ASR mitigation

• MN – Silica fume for deck overlays and SCMs specified for ASR mitigation

• NE – ASR mitigation

• ME – ASR mitigation

• SD – Prevention of ASR

• TN – SCMs are allowed in these areas, but not required.

• CO – Used to mitigate ASR and sulfate attack

• MI – ASR mitigation

Table B5. Q5: Does your DOT specification allow the use of the following SCMs in concrete?

Responded: 41

Other responses:

• MA – Looking into nanosilica, sublime systems, and recycled ground glass

• LA – Metakaolin

• TX – Metakaolin

• IL – High-reactivity metakaolin, and blended SCMs per ASTM C1697, except commingling is not an acceptable means of blending and the component SCMs do not need to conform to their individual standards (i.e., we’re allowing “in spec” and “off spec” fly ashes to be blended to create an “in spec” product)

• VT – GGP

• NC – Class N pozzolans

• MN – Recently approved natural pozzolans haven’t really been used yet

• CA – Ultrafine fly ash

• WA – WSDOT specifies fly ash conform to AASHTO M 295; if a harvested fly ash was submitted it would be allowed as long as it conformed to AASHTO M 295 Class C or F along with optional chemical requirements in table 2.

Table B6. Q6: What percent SCM is permitted by your DOT specification as replacement of cement in pavement concrete?

Responded: 41

Other:

• MA – silica fume 15%

• LA – Pavements allow up to 50% replacement of Portland cement (including PLC/Type IL) with combinations of slag and ash. Structural and mass concrete allow up to 70% replacement of Portland cement (including PLC/Type IL). Do not exceed the percent slag with fly ash. When using fly ash add at equal rates.

• IL – Max 35% slag allowed

• VT – We do not currently pave with concrete at all.

• NC – Fly ash C – No maximum set.

• CT – Silica fume max % waived for low-permeability concrete.

• MN – 33% Class C or Class F fly ash, 35% slag. Silica fume not used.

• NE – Slag – 38%

• ME – No spec limit on silica fume

• TN – 35% slag; 10%–20% silica fume

• NY – NYSDOT is moving toward Performance Engineered Concrete mixes. Starting with projects let after May 1st, 2024, there will not be limits on the amount of SCM permitted. The contractor/producer will determine how much is needed to meet the performance criteria in the specification and show performance is met through test results.

• CA – For pavement, individual SCMs must be proportioned in accordance with the requirements of Sec. 90-1.02B (3), which allows for the use of multiple SCMs in amounts related to the total specified cementitious material quantity.

• UT – Need to use 20 – 30% Fly ash F or natural pozzolans

• FL – 70% slag for pavements and bridges

• WI – Up to 30% for fly ash, if on Approved Products List for both pavements and structures

• WA – 35% for F and C ash for pavements and bridges

• MS – In combination with Type IL cement, fly ash F replacement is allowed up to 35%

• PR – Slag is also allowed at 65% for pavements and structures.

• IA – 35% for GGBFS, total replacement limited to 50% for pavements and structures.

• MT – Silica fume may be included up to 5% when a minimum of 15% FA [fly ash] or slag is included in the design or acceptable blended cements for pavements and structures.

Table B7. Q7: What percent SCM is permitted by your DOT specification as replacement of cement in bridges and other structures?

Responded: 41

Table B8. Q8: What percent natural pozzolan is permitted by your DOT specification as replacement of cement in concrete mixtures? Place “0” if not allowed or natural pozzolans not included in specification.

Responded: 41

Comments:

• CA – For concrete structures, natural pozzolans must be proportioned in accordance with the requirements of Sec. 90-1.02B (3), which allows for the use of multiple SCMs in amounts related to the total specified cementitious material quantity. SCMs must be proportioned in accordance with Sec. 49-3.01B (2) for mass concrete piles, 90-1.02I(2)(a) for structures in freeze–thaw zones, 90-1.02I(2)(b) for concrete exposed to deicing chemicals, and 90-4.02 for precast concrete elements. The use of rice husk is only allowed in minor concrete, per the requirements of Sec. 90-2.02B.

• NY – No limit specified. Allowed in PEM concrete to achieve desired performance characteristics. Also, natural pozzolans are not commonly used but are allowed.

• MA – Natural pozzolans have not been included in specifications, but 30% shall meet fly ash type F.

• VA – Metakaolin 7%–10%.

• LA – Allowable metakaolin at 50%

• IL – Natural pozzolans have not been included in specifications, but being considered

• MN – Natural pozzolans have not been included in specifications – recently allowed, determining percentages based upon type of natural pozzolan

• NE – Natural pozzolans have not been included in specifications – 25%

• OH – Natural pozzolans have been included in specifications but are not used at this time.

• FL – Natural pozzolans have not been included in specifications.

• WA – 35% calcined pumice

• MS – Allowable percent metakaolin 15%

• IA – Calcined clay, shale, and pumice, and metakaolin, 20%, provided material complies with ASTM C618

• MT – Metakaolin 20%. Natural pozzolans have not been included in specifications, approved only if meets AASHTO M 295 class F or C specifications.

Table B9. Q9: Does your DOT specification allow the use of the two SCMs in concrete mixtures (ternary mixtures)?

Responded: 33

Table B10. Q10: What SCM percentages in ternary concrete mixtures are permitted by your DOT specification or special project provisions?

Responded: 29

Other percentages:

• TX – Slag + silica fume: 35% +<10

• LA – Pavements allow up to 50% replacement of Portland cement (including PLC/Type IL) with combinations of slag and ash. Structural and mass concrete allow up to 70% replacement of Portland cement (including PLC/Type IL). Do not exceed the percent slag with fly ash. When using fly ash, add at equal rates. Silica fume content is usually limited to a maximum of 10% by the producer.

• PA – Fly ash F 15%, fly Ash C 15%, slag 25%. Silica fume 5%–10%

• IL – Max 35% total SCMs, and each cannot exceed specified individual limits (25% F, 30% C, 35% Slag, 10% silica fume or HRM). However, mass pours allow 65% SCMs with individual limits of 40% fly ash, 65% slag, and 5% silica fume or HRM.

• VT – 25% slag + 5% SF [silica fume]

• NC – Ternary mixtures are rare. No limits have been set.

• MN – Ternary mixes not specified anywhere except for ASR mitigation when using ternary

• ME – We only have limits on individual SCMs. The limits will apply to ternary blends.

• TN – Require 50% minimum cement in ternary concrete mixtures

• MI – Total SCM content for fly ash and slag cement is 40%, slag + silica fume is 25% slag + 4% silica fume.

• OH – Max per spec. For each item and total max of 50. Silica fume is max 10%, ashes are max 25%, and slag is max 30%. Any combination to get to 50% is allowed. Mass concrete is allowed more freedom based on Thermal Control Plan submittals.

• NY – 20% Fly ash or slag, with 6% silica fume is what is typically used. PEM concrete will not [have] restrictions on the amount of SCM if performance is met.

• CA – For concrete structures, individual SCMs must be proportioned in accordance with the requirements of Sec. 90-1.02B (3), which allows for the use of multiple SCMs in amounts related to the total specified cementitious material quantity. SCMs must be proportioned in accordance with Sec. 49-3.01B (2) for mass concrete piles, 90-1.02I(2)a) for structures in freeze–thaw zones, 90-1.02I(2)(b) for concrete exposed to deicing chemicals, and 90-4.02 for precast concrete elements.

• UT – One plant uses 25% natural pozzolan and 5% fly ash.

• FL – Also allow 40% FA and 10% SF

• WA – Slag up to 50% with silica fume could use 10% silica fume. Also allow fly ash and slag allow up to 40% or 50% by weight of the cementitious materials depending on concrete mix type.

• MS – Only ternary mixtures currently allowed in concrete with blended cement + SCM

• MT – Furnish low-alkali hydraulic blended cement in accordance with AASHTO M 240, Type IL, IP, IS or IT. When fly ash or ground granulated blast-furnace slag (GGBFS) is used in blended cement, limit the replacement amount to the maximums specified in Subsection 551.03.2(A) (5). Same as noted in question 7.

• CO – No set blend. Total substitution not to exceed 50% by mass.

Table B11. Q11: Does your DOT specification allow the use of the three SCMs as replacement of cement in concrete mixtures (quaternary mixtures)?

Responded: 39

Table B12. Q12: Does your DOT specification require concrete with SCMs to meet the acceptance strength requirements at 28 days?

Responded: 33

Comments:

• MN – We have allowed 56-day for HPC bridge deck mixes.

• CA – Sec. 90-1.01D (5) of the Standard Specifications allows for 42 days to attain required strength for mix designs with specified strength greater than 3,600 psi. For mix designs meeting specific SCM proportions described in this section, and not for use in freeze–thaw areas, this may be extended to 56 days.

Following are URLs for specifications that include acceptance of concrete strength at later ages than 28 days:

Florida:

https://fdotwww.blob.core.windows.net/sitefinity/docs/default-source/programmanagement/implemented/specbooks/fy-2023-24/fy2023-24ebook.pdf?sfvrsn=6b69416d_2 Section 346-3.4

Montana:

https://www.mdt.mt.gov/business/contracting/standard-specs.aspx - Section 551.03.2(A)(8)(b).

Rhode Island:

https://www.dot.ri.gov/business/bluebook/docs/Blue_Book_08_2023.pdf

Texas:

https://ftp.dot.state.tx.us/pub/txdot-info/cmd/cserve/specs/2014/prov/sp421012.pdf (Table 8)

Vermont:

https://outside.vermont.gov/agency/VTRANS/external/docs/construction/02ConstrServ/PreContract/2024%20Spec%20Book/2024%20Standard%20Specifications%20for%20Construction%20(2009%20MUTCD).pdf

Table B13. Q13: Does your DOT specification require the tests below when SCMs are used in concrete?

Responded: 24

States shared these URLs for their specifications:

Colorado:

https://www.codot.gov/business/designsupport/cdot-construction-specifications/2023-construction-specifications/2023-specs-book/2023-division-600

Florida:

https://fdotwww.blob.core.windows.net/sitefinity/docs/default-source/programmanagement/implemented/specbooks/fy-2023-24/fy2023-24ebook.pdf?sfvrsn=6b69416d_2 Section 346-7

Iowa:

https://www.iowadot.gov/erl/current/GS/content/2301.htm

Montana:

https://www.mdt.mt.gov/business/contracting/standard-specs.aspx, Deck structure and overly.

Rhode Island:

https://www.dot.ri.gov/business/bluebook/docs/Blue_Book_08_2023.pdf

Utah:

https://www.udot.utah.gov/connect/business/standards/

Vermont:

https://outside.vermont.gov/agency/VTRANS/external/docs/construction/02ConstrServ/PreContract/2024%20Spec%20Book/2024%20Standard%20Specifications%20for%20Construction%20(2009%20MUTCD).pdf

Washington:

https://wsdot.wa.gov/engineering-standards/all-manuals-and-standards/manuals (Note: this is for deck concrete: 4000D).

Table B14. Q14: Have SCMs affected the performance of concrete mixtures with Type IL cement?

Responded: 33

Table B15. Q15: What impacts do SCMs have on concrete with Type IL cement?

Responded: 9

Comments:

• LA – Generally the move to IL has been very positive. Increased long-term strengths with minor adjustments compared to regular Type I/II mixtures containing SCMs. We have not observed shrinkage issues and delayed strength issues.

• IL – Anecdotally, it seems the primary complaints since switching to Type IL cement are that early strengths can be impacted and that admixture use/dose may need considerable adjustment. But these complaints are not widespread and are typically considered specific to individual concrete plants. I think the net effect of these SCMs with Type IL is still positive, but there may be aspects of our specs (e.g., 14-day strength) that are made problematic by the use of less ordinary Portland cement.

• ME – Our state commonly uses SCMs but recently switched to Type IL with a 1:1. Our experience isn’t how SMC effect Type IL but how Type IL is different than Type II.

• OH – Contractor complaints are ability to get on earlier than normal. Admixture adjustments and other controls by ready-mix suppliers occur regularly and they are still learning.

Table B16. Q16: Is your state experiencing shortage of fly ash to supply DOT projects, or has your state experienced shortages in the past?

Responded: 33

Table B17. Q17: What actions are being taken (or have been taken in the past) by your DOT to address the challenge of fly ash shortages?

Responded: 29

Other actions:

• DE – Primarily use slag

• TX – Proposing off-spec SCM specifications

• IL – Our largest district will prohibit the use of fly ash on certain large paving projects so as to not tie up supply. One large concrete supplier imports slag due to unreliable ash supply.

• AZ – Using 100% cement

• MN – Currently exploring a performance-based spec for off-spec ashes

• WA – In the process of working with industry to update specifications for alternative SCMs

Table B18. Q18: Does your DOT allow use of alternative SCMs (ASCMs) in concrete?

Responded: 33

Table B19. Q19: Does your DOT permit the use the of following ASCMs in concrete mixtures?

Responded: 13

Comments:

VT – Any ASCM with an ASTM or AASHTO spec will be allowed in our performance-based concrete spec if industry asks for it.

MN – Exploring alternative materials at MnROAD Research Facility through NRRA pooled fund

CO – Any ASCM that meets AASHTO M 321

Table B20. Q20: What percent ASCM is permitted by your specification as replacement of or in addition to of cement in concrete?

Responded: 9

Respondents from a few states that permit or have specifications for ASCMs shared their specifications:

Colorado:

https://www.codot.gov/business/designsupport/cdot-construction-specifications/2023-construction-specifications/2023-specs-book/2023-division-600

Florida:

Specification 929-6 (page 1036) – https://fdotwww.blob.core.windows.net/sitefinity/docs/default-source/programmanagement/implemented/specbooks/fy-2023-24/fy2023-24ebook.pdf?sfvrsn=6b69416d_24

New York:

https://www.dot.ny.gov/main/business-center/engineering/specifications/english-spec-repository/2024_5_specs_usc_tc_vol4.pdf. Ground Glass is under Standard Specification 711-15 “Miscellaneous Supplementary Cementitious Materials.” The specification was written prior to ASTM C1866 and there are future plans to align this specification with the ASTM.

Vermont:

https://outside.vermont.gov/agency/VTRANS/external/docs/construction/02ConstrServ/PreContract/2024%20Spec%20Book/2024%20Standard%20Specifications%20for%20Construction%20(2009%20MUTCD).pdf

Table B21. Q21: Which test results does your DOT typically require for ASCM consideration for approval?

Responded: 10

Colorado and Utah ASCM specifications:

Colorado:

https://www.codot.gov/business/designsupport/cdot-construction-specifications/2023-construction-specifications/2023-specs-book/2023-division-600

Utah:

https://www.udot.utah.gov/connect/business/standards/

Table B22. Q22: Would your department accept test results on ASCM performance from producers, private laboratories, vendors, product champions, or other states to support approval of ASCMs for use?

Responded: 13

Table B23. Q23: Has your agency supported/performed field trials of ASCMs?

Responded: 13

Other comments:

New York:

Ground glass is under Standard Specification 711-15 “Miscellaneous Supplementary Cementitious Materials.” The specification was written prior to ASTM C1866 and there are future plans to align this specification with ASTM.

https://www.dot.ny.gov/main/business-center/engineering/specifications/english-spec-repository/2024_5_specs_usc_tc_vol4.pdf

Table B24. Q24: What type of field trial(s) has your department supported/performed or will support/performed to evaluate ASCM performance?

Responded: 7

Minnesota DOT shared the final report of its completed filed trials and indicated that three more trials are underway: https://www.dot.state.mn.us/mnroad/nrra/structure-teams/rigid/sustainable-concrete-mix-selection.html.

Table B25. Q25: Would you agree to participate in a short case example interview?

Responded: 24