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SPECIFYING MANUFACTURED SANDS FOR CONCRETE APPLICATIONS

SPECIFYING MANUFACTURED SANDS FOR CONCRETE APPLICATIONS. Vute Sirivivatnanon Associate Professor of Construction Materials University of Western Sydney Ion Dumitru Chairman – Manufactured Sands Research Steering Committee Cement Concrete & Aggregate Australia. CONTENTS.

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SPECIFYING MANUFACTURED SANDS FOR CONCRETE APPLICATIONS

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  1. SPECIFYING MANUFACTURED SANDS FOR CONCRETE APPLICATIONS Vute Sirivivatnanon Associate Professor of Construction Materials University of Western Sydney Ion Dumitru Chairman – Manufactured Sands Research Steering Committee Cement Concrete & Aggregate Australia

  2. CONTENTS • Sustainability measures in construction materials • Optimum use of natural & manufactured sands • Important sand characteristics to all concrete • Important sand characteristics to concrete pavement • CCAA/RMS collaborative study • Performance-based specifications 2

  3. SUSTAINABILITY MEASURES INCONSTRUCTION MATERIALS 3

  4. OPTIMUM USE OF SANDSNATURAL SAND Recovered from geologically recent deposits such as • Morton Bay, • Kurnell dunes, and • Nepean River flood plain Excellent fine aggregate from geological processes of shaping and sorting resulting in • Rounded to sub-rounded and smooth surface • Removal of weaker minerals 4

  5. OPTIMUM USE OF SANDS MANUFACTURED SAND Suitable source rock purpose-made throu • Crushing, • Screening (sizing & blending), and • possible washing to control microfines ≠crusher dusts as blend component in road bases, fills, fines, and stabilized crusher fill. 5

  6. IMPORTANT CHARACTERISTICS TOALLCONCRETE GRADING, SHAPE & TEXTURE, FREE OF DELETERIOUS FINES, DURABLE & NON REACTIVE, GOOD SKID RESISTANCE The challenge is to apply engineering knowledge to the best & economical use of manufactured sands through appropriate specifications 6

  7. IMPORTANT CHARACTERISTICSTO ALL CONCRETE 7

  8. IMPORTANT CHARACTERISTICSTO ALL CONCRETE 8

  9. IMPORTANT CHARACTERISTICSTO CONCRETE PAVEMENT Concrete pavement must be fit for purpose • Resistance to wear (abrasion of texture) • Good skid resistance in wet and dry condition Skid resistance depends on the complementary functions of macro- & microtexture • Microtexture: λ< 0.5mm • Macrotexture: 0.5<λ< 50mm 9

  10. MACROTEXTUREIN SKID & ABRASION RESISTANCE MACROTEXTURE Weller and Maynard (1970) • Tyned grooves provide drainage to prevent hydroplanning • Mechanical resistance to skiding Shackelet al.,(1994) • Dependent on mix & curing ICAR Barborak and Rached, (2010) • Effect of textures & travel speed on skid (friction) S Bulahdelah Mittagong Bypass 10

  11. Effect of textures on skidICAR Barborak and Rached, (2010) Tined+Carpet Broom Finish Carpet Drag Smooth Grass 11

  12. Mineralogical compositions Silica Content MAN SAND TESTING Micro-Deval - abrasion Na2SO4 Soundness - stability Absorption – stability MBV x Passing 75-micron - durability Historical perspective Source Rocks ▼ Coarse Aggregates ▼ Man Sands Micro-Deval Apsortion LAB CONCRETE TESTING Skid before & after wear Wear loss (AS 1141.41) Abrasion loss (AS 4456.9) Performance Criteria Lab-prepared Concrete Specimens Natural Sand FIELD ASSESSMENTS SCRIMS and other by Road Authority Field-retrieved Concrete specimens Figure 1 EFFECT OF SAND ON MICROTEXTURESKID & ABRASION RESISTANCE 12

  13. MANUFACTURING & TESTING OF CONCRETE3 Natural sands and9 Manufactured sands at 50% & 80% of total fine 13

  14. Sand durability tests • Micro-Deval • % abrasion in water • Sodium Soundness • stability due to expansive salt crystallization • Absorption • Porosity • Free Silica Content • Petrography • Chemical 14

  15. RMS Collaboration - Tarcutta Range test site 15 Truck Rest Test site is on the S/B, opposite the entrance to the Truck Bay To Wagga Wagga 2820

  16. Skid of various surfaces from lab-prepared & field sampled Tynedsurface Field sample skid after wear of workmanship-independentsurfaces Sawn surface Lab sample Off-form surface 16

  17. Pendulum friction test (AS 1141.42)Friction Value FV 17

  18. PAFV abrasion resistance (AS 1141.41)33-35 revs/min (8,000&16,000 cycles after 4 & 8 hours) 2-hr with coarse abrasion [Balck silicon carbide No. 320 @ 2g/min] 2-hr with fine abrasion [Optical emery No. 600 @ 2g/min] 18

  19. Abrasion index (AS 4456.9)4 circular faces subjected to 600 steel balls60 rev/min x 1 hr = 3600 cycles 19

  20. Skid (friction) after abrasion by PAFVof off-form concrete Intrinsic Skid 20

  21. Skid (friction) after abrasion by PAFVof saw-cut concrete

  22. “Characteristic skid resistance ”Common skid resistance of off-form & saw-cut surfaces after 4-5 hrs of polishing Characteristic skid 22

  23. Relating skid resistanceof various surfaces Lab-prepared concrete Field-sampled concrete SCRIM Intrinsic Skid Characteristic Skid Resistance Sand properties Off-form 8-hours polishing Off-form 4-hours polishing Saw-cut 4-hour polishing Saw-cut 4-hour polishing Tyned 23

  24. Skid after wear of concrete with various sands SCRIM results: Mittagong 68, 71 Tarcutta 74, 68 24

  25. Intrinsic Skid and micro-Deval or free silica content of Sands 83% Corr 25

  26. Fowler and Rached, ‘Evaluation of the Polish Resistance of Fine Aggregates in PCC Pavements’,( to be published in TRR) 26

  27. Abrasion is largely a function of strengthand independent of type of sand 65% Corr 27

  28. Possible performance-based specifications for concrete pavement NATURAL & MANUFACTURED SANDS • Micro-deval≤15% for skid after wear or CONCRETE PAVEMENT (LAB) • Characteristic skid > 50 for off-form surface • A nominated concrete strength for abrasion resistance (independent of sand used) 28

  29. CONCLUSIONS CCAA research has lead to • Abetter understanding of how to specify fit-for-purposemanufactured sands for all concrete applications. Specifications are introduced into AS 2758.1 (2012) • Critical property of sands to concrete pavements is durability (Micro-Deval) for skid after wear& concrete strength for abrasion resistance • Important properties to concrete producer are shape, surface texture & consistent grading. 29

  30. CCAA PUBLICATIONS ON MANUFACTURED SAND Manufactured Sand – National test methods and specification valueshttp://www.concrete.net.au/publications/pdf/ManSand.pdf Guide to the Specification and Use of Manufactured Sand in Concrete http://www.concrete.net.au/publications/pdf/GuideManSand.pdf Manufactured Sand - Abrasion resistance and effect of manufactured sand on concrete mortarhttp://www.concrete.net.au/publications/pdf/ManuSandReport2.pdf Effect of manufactured sands on surface properties of concrete pavement (to be available on CCAA website shortly) 30

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