UFGS 32 13 14 Airfield Concrete Mix Design LESSONS LEARNED By: - PowerPoint PPT Presentation

UFGS 32 13 14 Airfield Concrete Mix Design LESSONS LEARNED By: Richard L. Allen, PE BOWSER-MORNER, INC.

AGGREGATE QUALIFICATION ISSUES • It can be difficult to identify aggregates that meet UFGS 32 13 14 in some regions. • Aggregate producers are often unfamiliar with the specification. • Do not assume that an aggregate meeting State DOT requirements will meet UFGS 32 13 14 Table 5. • The desire for 1 ½” NMA sizes (AASHTO #4) contributes to problems in sourcing aggregates. Large coarse aggregates tend to have more issues with ASR-deleterious materials than smaller sizes (i.e. #57s, #67s) due to less beneficiation during production. • Extra beneficiation ($$) may be necessary to qualify some materials. • Consider allowing well-graded mixes without #4s when appropriate.

AGGREGATE TESTING TIME LINE Sampling ± 2 days ASTM C666A Freeze/Thaw Durability ± 90 days ASR Rapid Mortar Bar ± 35 days ASR Mitigation Trials ± 35 days UFGS 32 13 14 Table 5 Deleterious Exam ± 30 days ASTM C33 Full Quality Analysis ± 30 days Even when tests are run concurrently it takes a minimum of 92 days to qualify aggregates per UFGS 32 13 14. ALSO - Per spec, these tests cannot be run sooner than 120 days before production.

MIX DESIGN TESTING TIME LINE TIME REQUIREMENTS: The time requirements for mix review and approval also need to be considered. • Sampling (± 18 - 55 gallon drums of material are required) ± 2 days • Proportioning by Design Engineer ± 2 days • Trial Batching (Small Batches – ASTM C192) ± 7 days • Production Batching (large batches – ASTM C192) ± 14 days • Strength testing – Compressive & Flexural (ASTM C39 & C78) ± 90 days • Final Data Review and Lab Report ± 2 days It takes a minimum of ± 115 days to perform trial mixing per UFGS 32 13 14 and prepare a design report

June 2020 July 2020 August 2020 September 2020 Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 6 4 1 6 1 2 3 4 5 1 2 3 1 2 3 4 7 10 11 12 13 5 10 11 2 8 7 10 11 12 13 8 9 6 7 8 9 3 4 5 6 7 8 9 14 15 16 17 18 19 20 12 13 14 15 16 17 18 9 10 11 12 13 14 15 14 15 16 17 18 19 20 21 22 23 24 25 26 27 19 20 21 22 23 24 25 16 17 18 19 20 21 22 21 27 AGGREGATE TESTING 28 29 30 26 27 28 29 30 31 23 24 25 26 27 28 29 28 30 31 NORMAL TIMELINE October 2020 November 2020 December 2020 January 2021 Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 3 1 7 5 2 AGGREGATE 4 10 8 14 6 12 3 9 Qualify Aggregate First, AGGREGATE AGGREGATE TESTING AGGREGATE 11 17 15 21 13 TESTING & MIX 19 10 TESTING & MIX 16 TESTING then run Mix Designs DESIGN TESTING DESIGN TESTING 18 24 22 28 20 26 17 23 AGGREGATE & MIX DESIGNS 25 29 27 24 30 February 2021 March 2021 April 2021 May 2021 Minimum 207 days Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 6 6 3 1 7 13 7 13 4 PLANT SET-UP 10 2 TRIAL BATCHING 8 MIX DESIGN MIX DESIGN & UNIFORMITY 14 TESTING & 20 14 REVIEW & 20 11 17 9 15 REPORT ACCEPTANCE 21 27 21 27 18 PLANT 24 16 22 TEST STRIP CERTIFICATION 28 28 25 31 23 29 30 31 June 2021 July 2021 August 2021 September 2021 Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 5 1 2 3 1 2 3 4 5 6 7 1 2 3 4 6 12 4 10 8 10 11 12 13 14 5 10 11 5 6 7 8 9 9 6 7 8 9 PRODUCTION 13 19 11 12 13 14 15 16 17 15 16 17 18 19 20 21 12 13 14 15 16 17 18 PAVING 20 26 18 19 20 21 22 23 24 22 23 24 25 26 27 28 19 20 21 22 23 24 25 27 33 25 26 27 28 29 30 31 29 30 31 26 27 28 29 30

June 2020 July 2020 August 2020 September 2020 Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 1 2 3 4 5 6 1 2 3 4 1 6 7 8 9 10 11 12 13 5 6 7 8 9 10 11 2 3 4 5 6 7 8 7 13 AGGREGATE 15 16 17 18 19 13 14 15 16 17 14 20 12 18 9 15 14 20 TESTING AGGREGATE 21 22 23 24 25 26 27 19 20 21 22 23 24 25 16 22 21 27 TESTING 28 29 30 26 27 28 29 30 31 23 29 28 30 31 “COMPRESSED” October 2020 November 2020 December 2020 January 2021 Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa TIME LINE 3 1 7 5 2 AGGREGATE 4 10 8 14 6 12 3 9 TESTING AGGREGATE MIX DESIGN MIX DESIGN 11 17 15 21 13 19 10 16 TESTING TESTING TESTING 18 24 22 28 20 26 17 23 MIX DESIGN Begin trial batching as soon TESTING 25 29 27 24 30 as Table 5 Deleterious and ASTM C33 Results are done. February 2021 March 2021 April 2021 May 2021 (RISKIER) Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 6 6 3 1 7 13 7 13 4 PLANT SET-UP 10 2 8 TRIAL BATCHING & MIX DESIGN MIX DESIGN TESTING & REVIEW & UNIFORMITY 14 20 14 20 11 17 9 15 REPORT ACCEPTANCE 21 27 21 27 18 24 16 22 PLANT TEST STRIP Minimum 152 days CERTIFICATION 28 28 25 31 23 29 30 31 June 2021 July 2021 August 2021 September 2021 Su Mo Tu We Th Fr Su Mo Tu We Th Fr Su Mo Tu We Th Fr Su Mo Tu We Th Fr Sa Sa Sa Sa 5 1 2 3 1 2 3 4 5 6 7 1 2 3 4 6 12 4 5 6 7 8 9 10 8 9 10 11 12 13 14 5 6 7 8 9 10 11 PRODUCTION 13 19 11 12 13 14 15 16 17 15 16 17 18 19 20 21 12 13 14 15 16 17 18 PAVING 20 26 18 19 20 21 22 23 24 22 23 24 25 26 27 28 19 20 21 22 23 24 25 27 33 25 26 27 28 29 30 31 29 30 31 26 27 28 29 30

AGGREGATE OPTIMIZATION FOR MIX DESIGNS Recommendations: 1) Obtain aggregate gradation data for previous ± 6 months (CA & FA) • Determine average gradations as produced. • Determine min/max limits for each sieve size. • Compare to samples submitted during lab quality testing. 2) Use the average gradations for aggregate blending calculations and for calculating the Coarseness Factor (CF) and Workability Factors (WF) for the mix. 3) Use the min/max data from recent gradations to check likely range of aggregate variation during the project. This can give you insight into what type of mix variability you can expect during the project.

AGGREGATE OPTIMIZATION FOR MIX DESIGNS Min/Max Aggregate Data can be used to predict likely range of variations during project

AGGREGATE OPTIMIZATION FOR MIX DESIGNS This approach allows you to tailor (to some degree) mix properties to fit planned methods of placement. Need 2 or 3 Coarse Aggregates for Maximum Flexibility

AGGREGATE OPTIMIZATION FOR MIX DESIGNS

AGGREGATE OPTIMIZATION FOR MIX DESIGNS “Tarantula” Curve

TRIAL BATCHING REQUIRES A LOT OF LABORATORY EFFORT! 3 Mixes x 6 break dates x 6 samples per break result in 108 samples and 18 different batches LOW POINT MID POINT HIGH POINT

OTHER MIX DESIGN ISSUES re: Supplementary Cementitious Materials for ASR Control Fly Ash • Will the design source be available at the time of construction? • What is your back-up plan if it is not & what acceptance procedure will be needed? • Some clients are duplicating mix designs with other SCM’s just in case. • Remember that Fly Ash will suppress early strengths (including 28-day strengths) Lithium Nitrate • Lithium is in high demand for batteries of electronic devices, hybrid cars, etc., etc. Natural Pozzolans • Meta kaolin is being considered for some non UFGS projects. • Some regions are seeing cement blended with limestone micro fines

OTHER MIX DESIGN ISSUES

OTHER MIX DESIGN ISSUES (Cont.) HANGAR SLABS • Will these be AE or NAE Mixes? • Will a separate mix design be required? • What slump limits will be allowed? • Will contractor have to work around hydronic heating elements?

PRE-PRODUCTION ISSUES CONDUCT PRE-PRODUCTION BATCHING TO VERIFY MIX PROPERTIES. Do not assume that mixes will perform the same in regular production as they did in the laboratory setting! You will need to adjust mixing times, admixture dosages and air adjustments to adapt the trial mix for field purposes. Do not wait until the day of the test lane placement to figure this out! When adjusting for air and slump, always put all of the design mix water in, then adjust admixtures . Failure to include all of the design mix water will result in: 1. Surfaces that are stickier and more difficult to finish. 2. Wide fluctuations in test results. 3. Non- predictable strength performance (you’ve changed the mix from what was designed). Only change the water content with the designer’s knowledge and approval.

CONCRETE PRODUCTION CQC ISSUES The loader operator at the batch plant will have a significant impact, for better or for worse, on the success of the project.

CONCRETE PRODUCTION CQC ISSUES (Cont.) CF and WF ratios are controlled by a very small portion of the aggregate, so getting representative samples is a critical process. It is possible for individual aggregate gradations to be within specification limits, but for CF & WF to vary outside of project limits!