BASICS OF AGGREGATES. Aggregate Quality Monitoring Program Tex-499-A

Transcription

1 BASICS OF AGGREGATES Aggregate Quality Monitoring Program Tex-499-A Michael Dawidczik, P.G. Construction Division/Materials & Pavements Section Geotechnical, Soils, & Aggregates Branch October 11, 2017

2 Table of contents 1 Aggregate Quality Monitoring Program (AQMP) Purpose & Responsibilities of AQMP Products & Laboratory Tests of AQMP Laboratory Tests of AQMP in Detail Process of Adding & Removing Sources from AQMP Questions 41 2

3 Aggregate Quality Monitoring Program Aggregate Quality Monitoring Program (AQMP) managed by the Geotechnical, Soils and Aggregates Branch within TxDOT s Construction Division/Materials & Pavements Section (CST/M&P) Monitors the quality of aggregate products supplied to TxDOT projects Single sources are included based on the testing history of aggregate products used for TxDOT construction projects Bituminous coarse aggregate Concrete fine aggregate Concrete coarse aggregate Micro-surfacing aggregate 3

4 Aggregate Quality Monitoring Program Durability laboratory tests performed biannually for each source: L.A. Abrasion Magnesium Sulfate Soundness Micro-Deval Acid Insoluble Coefficient of Thermal Expansion (CoTE) Statistical evaluation of recent testing history Rated values produced and published online & reported in Site Manager Bituminous Rated Source Quality Catalog (BRSQC) Concrete Rated Source Quality Catalog (CRSQC) 4

5 What is the AQMP? Sources currently in the program are located in: Texas New Mexico Oklahoma Arkansas Louisiana Mexico. 97 sources on the BRSQC 168 sources on the CRSQC 61 sources on both catalogs 5

6 Aggregate Sources on the BRSQC and CRSQC 6

7 The Purpose of the AQMP Provides requirements & procedures for CST/M&P to monitor aggregate products demonstrating continuous quality and uniformity Allows TxDOT Districts to use the rated values from sources on the AQMP without project specific testing Districts do not have to perform laboratory tests on AQMP Expedites acceptance of aggregate meeting specification requirements Provides continuous quality assurance of aggregate products 7

8 Polling Question #1 Which District has the most sources listed on the AQMP? 8

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10 Responsibilities CST/M&P TxDOT Districts Aggregate Producers 10

11 Responsibilities CST/M&P Requesting Quality Monitoring (QM) samples biannually Laboratory testing of QM, project & informational samples for properties listed on AQMP Performing & reporting test results Maintaining the BRSQC and CRSQC Notifying Districts & aggregate producer of any quality concerns Evaluation of source s quality control plan and test results Did you know? Over the last 10 years, CST/M&P - Aggregates Lab on average has completed the testing of 1650 samples annually. 11

12 Responsibilities TxDOT Districts Sampling QM & project samples and providing documentation Shipping or delivering samples to CST/M&P Offering split samples at the time of sampling with aggregate producer Job control (project level) testing Final acceptance of aggregate Submitting a QM sample from project when material has questionable quality Safety - Signing in/out at the quarry & following site specific safety procedures Did you know? The San Antonio District has the most sources on the AQMP and the Tyler District has the least. 12

13 Responsibilities Aggregate Producers Notifying CST/M&P of changes in ownership and maintaining current contact information Submitting a mining & quality control plan, GPS data and requested documents Submitting driving directions to the source from District Lab Maintaining identification of stockpiles at the quarry at all times Notifying CST/M&P and the District if split samples are desired Did you know? Since 2000, the Aggregates Lab has tested aggregate from over 450 sources. 13

14 Polling Question #2 How often are the aggregate MPLs updated within a year? 14

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16 Products and Tests Covered in AQMP Laboratory Tests Aggregate Products L.A. Abrasion (Tex-410-A) MgSO 4 Soundness (Tex-411-A) Micro-Deval (Tex-461-A) Acid Insoluble Residue (Tex-612-J) CoTE (Tex-428-A) Concrete Fine Aggregate Concrete Coarse Aggregate Bituminous Coarse Aggregate Micro-Surfacing Aggregate 16

17 Products and Tests Covered in AQMP SAC A SAC B SAC C Magnesium Sulfate Soundness (Tex-411-A) Maximum value Acid Insoluble Residue (Tex-612-J) Minimum value Crushed Face Count (Tex-460-A) Minimum value Surface Aggregate Classification (SAC) As determined in Tex-499-A, Table 1 17

18 Polling Question #3 How many project samples are necessary to complete before the rated values can be calculated? 18

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20 AQMP Tests L.A. Abrasion Performed in accordance to Tex-410-A (ASTM C131) Resistance to degradation by impact and abrasion forces Test samples of different gradations A, B, C, and D 500 revolutions at 33 rpms Steel spheres with a diameter of ~2 inches and weight of ~1 lb Loss determined by material passing the #12 sieve Specification limits vary 20

21 L.A. Abrasion (Tex-410-A) 21

22 L.A. Abrasion Specification Limits Item 330, 340, 341, 421 Limestone Rock Asphalt (LRA), Dense-Graded HMA, Concrete 40% Item 302, 344 Seal Coat & Superpave HMA 35% Item 342, 346, 347, 348 Permeable Friction Course (PFC), Stone Matrix Asphalt (SMA), Thin Overlay Mixtures (TOM), & Thin Bonded Friction Courses 30% % 22

23 AQMP Tests Magnesium Sulfate Soundness Performed in accordance to Tex-411-A Resistance to degradation/disintegration by wetting and drying cycles Wetting duration of hours submerged in magnesium sulfate solution Drying duration of 4-6 hours in 230 F oven Rinse cycle in 110 F water until samples completely free of salt Magnesium Sulfate soundness solution temperature and specific gravity controls Loss determined by normalized gradation specific to product type Specification limits vary 23

24 Magnesium Sulfate Soundness (Tex-411-A) 24

25 Magnesium Sulfate Soundness (Tex-411-A) 25

26 Magnesium Sulfate Soundness Specification Limits Item 330, 340, 341, 421 Limestone Rock Asphalt (LRA), Dense-Graded HMA, Concrete 30% Item 302, 344, 350 Seal Coat & Superpave HMA, Microsurfacing 25% Item 342, 346, 347, 348 PFC, SMA, TOM, & Thin Bonded Friction Courses 20% % 26

27 AQMP Tests Micro-Deval Performed in accordance to Tex-461-A Resistance to degradation by abrasion forces Aggregate added to 3/8 diameter steel spheres and water for test Tested at 100 rpms for 120, 105, 95 or 15 minutes depending on gradation Rinsed over stacked sieves and oven dried to determine the loss No specification limit, used as quality control test 27

28 Micro-Deval (Tex-461-A) 28

29 AQMP Tests Acid Insoluble Residue Performed in accordance to Tex-612-J Resistance to dissolution by Hydrochloric (HCl) acid Test sample consists of 25 grams HCl acid added to sample until reaction is complete Sample rinsed with distilled or deionized water Specification limits for concrete fine aggregate and bituminous coarse aggregate to determine SAC 29

30 Acid Insoluble Residue Specification Limits Item 421 Fine Aggregate Hydraulic Cement Concrete 60% SAC A Hot-Mix Asphalt & Seal Coats 55% SAC B & C No Requirement % 30

31 AQMP Tests Coefficient of Thermal Expansion (CoTE) Performed in accordance to Tex-428-A Determine the thermal expansion of aggregate in concrete Standard mix design Test cylinders are cured for 28 days before testing Temperature cycling from 50 F to 120 F and reduced to 50 F 3 cycles and continuous data collection Specification limit of 5.5 µstrains/ F for Item 360 No project level testing for a source which has a rated value on the CRSQC 31

32 Coefficient of Thermal Expansion (Tex-428-A) 32

33 Polling Question #4 Does a source have to be on the AQMP in order to supply aggregate to a TxDOT project? 33

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35 AQMP Process of Adding Sources Informational Sample Provide Producer Quarry Information Aggregate Producer and District Informed Supply Aggregate Product to TxDOT Project Testing & Approval of Project Samples Mining Plan Submitted Catalogs Updated Site Manager Updated Ratings Developed for Aggregate Product 35

36 AQMP Process of Adding Sources Informational Sample Provide Producer Quarry Information One informational sample can be sampled and tested from final product stockpiles for each aggregate product per aggregate source Raw uncrushed/unprocessed rock will not be tested The results from the informational sample can be used to solicit material to contractors for potential use for TxDOT projects The informational sample does not count towards the AQMP and does not pre-approve a stockpile or source Owner of aggregate source completes Producer-Quarry Information form Ship samples to CST/M&P at Cedar Park Campus in Austin 36

37 AQMP Process of Adding Sources Supply Aggregate Product to TxDOT Project Testing & Approval of Project Samples Once the aggregate product from a source is being supplied to a TxDOT project(s), the aggregate producer will coordinate with the TxDOT District to begin sampling the stockpiles designated for the project Stockpile approval is on a stockpile by stockpile basis CST/M&P performs durability testing as testing lab for TxDOT Districts 37

38 AQMP Process of Adding Sources The aggregate producer is responsible for furnishing the mining plan and quality control testing of their aggregate Mining plan - a topographical or aerial map showing the property lines and shaded areas of current and future production Mining Plan Submitted Flow chart - description of the production of the aggregate from the ground to the final product in stockpiles Aggregate supplier s quality control testing plan and testing frequency Driving directions to pit or quarry 38

39 AQMP Process of Adding Sources Five project samples per aggregate product conforming to the items found in Section 4 of Tex-499-A are used to develop the rated value One month between each project sample Test results meet all the standard specification quality requirements Statistical ratings of the test results meet the standard specification requirements The results of the aggregate product are reviewed prior to being approved for addition to the AQMP Site Manager updated for District use Site Manager Updated Ratings Developed for Aggregate Product 39

40 AQMP Process of Adding Sources Catalogs Updated Aggregate Producer and District Informed The aggregate producer and the TxDOT District will be notified via of the source s addition to the AQMP The will contain the rated values, the AQMP producer code and the Site Manager producer code The online catalog will be updated accordingly with the next scheduled update For out of state/country sources, TxDOT must have access to aggregate stockpile(s) within Texas to sample for the AQMP to check for routine compliance and material consistency 40

41 Basics of Aggregates Questions? 41