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Asphaltic Concrete Mix Design Seksyen Loji Dan Kuari JKR Woksyop Persekutuan KL.

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Presentation on theme: "Asphaltic Concrete Mix Design Seksyen Loji Dan Kuari JKR Woksyop Persekutuan KL."— Presentation transcript:

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2 Asphaltic Concrete Mix Design Seksyen Loji Dan Kuari JKR Woksyop Persekutuan KL

3 Construction Of Road in the 60’s by JKR

4 STILL Little PROBLEMS IN ROAD RESURFACING ! Is this JKR Works After 100 Years

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6 Subgrade Road Structure Wearing Course BinderCourse` Roadbase Sub-base

7 Cracking

8 Cracking Why cracking in asphalt surfacing undesirable? 1.It allows surface water to penetrate into the lower pavement layers, causing localised weakening of the pavement structure. 2.It reduces the dynamic modulus of the surfacing, making it less able to distribute imposed traffic loads.

9 Possible Causes of Cracking 1.Excess fines in mixture. 2.Insufficient bitumen. 3.Insufficient compaction. 4.Improperly proportioned mixture. 5.Voids content too high. 6.Rolling when mixture too cold. 7.Overheating the bitumen. 8.Wet mixing time too long. 9.Improper joint preparation & construction. 10.Over Rolling - vibratory roller. 11.Too high amplitude - vibratory roller.

10 Rutting

11 Rutting Why rutting in asphalt surfacing undesirable? 1.It creates an irregular road profile, thus poor riding quality, dangerous to traffics. 2.It increases roughness, thus increases vehicle operating costs. 3.It allows surface water to accumulate, thus increases risk of skidding and aquaplaning, and water infiltration into pavement structure.

12 Possible Causes of Rutting 1.Excess bitumen. 2.Excess fines in mixture. 3.Improperly proportioned mixture. 4.Excessive tack coat. 5.Excessive segregation.

13 Skidding

14 Skidding Does asphaltic concrete road surfacing lack the necessary macrotexture for skidding resistance at high speeds ?

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16 Possible Causes of Smooth Surface Texture 1. Excess fines in mixture. 2. Excess bitumen. 3. Over rolling. 4. Rolling when mixture too hot. 5. Excessive segregation. 6. Abrasion of aggregates by traffic.

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18 Porous Asphalt The solution ?

19 Stone Mastic Asphalt

20 Component Of Asphalt Aggregate Aggregate Filler Filler Bitumen Bitumen

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24 Aggregate - The Major Component Of Premix Production.

25 BasaltGranite

26 Coarse Aggregate Testing 1 Test Per Stockpile Per 2,500 Tons Of Asphaltic Concrete Produced; * Aggregate Crushing Value. * Sodium Sulphate Soundness. * Flakiness Index. * Water Absorption. * Polished Stone Value (Wearing Course Only).

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28 Limestones in wearing course?

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31 Fine Aggregate Testing 1 test per stockpile per 2,500 tons of asphaltic concrete produced; * Sodium Sulphate Soundness. * Water Absorption.

32 Sand or quarry dust? Fine aggregate: Natural sand, mining sand or quarry fines.

33 Cement or limestone? Mineral filler: Rock dust, limestone dust, hydrated lime or hydraulic cement. Anti-stripping agent: Ordinary Portland cement. Material passing 75 um to bitumen ratio by weight Mineral Filler / Anti Stripping Agent

34 Bitumen grade: Penetration grade (MS 124) or ?

35 Bitumen Testing * Penetration. * Softening point. * Solubility in Trichloroethylene. * Ductility. * Flash point. * Retained penetration after thin film oven. * Loss on heating. Test frequency: Not stated in JKR Guidelines or JKR/SPJ. Recommends one set of test per every bitumen delivery to the plant.

36 BITUMEN QUALITY PENETRATION TEST penetration value in 0.1 mm 100 gramme needle bitumen at 25 degrees Celsius 5 seconds

37 Mix Design

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40 Mix Design Requirements 1.Grading of combined aggregates + filler - Table 4.8 JKR/SPJ. 2.Bitumen content - Table 4.9 JKR/SPJ. 3.Marshall method of mix design - Clause JKR/SPJ. 4.Test parameters of Marshall specimens - Table 4.10 JKR/SPJ. 5.Establish design aggregate grading and bitumen content with tolerances in Table 4.11 JKR/SPJ.

41 Mix Design Requirements 1.Grading of combined aggregates + filler - Table 4.8 JKR/SPJ. 2.Bitumen content - Table 4.9 JKR/SPJ. 3.Marshall method of mix design - Clause JKR/SPJ. 4.Test parameters of Marshall specimens - Table 4.10 JKR/SPJ. 5.Establish design aggregate grading and bitumen content with tolerances in Table 4.11 JKR/SPJ.

42 Table Gradation Limits For Asphaltic Concrete B.S. Sieve Size, mm% Passing By Weight

43 Mix Design Requirements 1.Grading of combined aggregates + filler - Table 4.8 JKR/SPJ. 2.Bitumen content - Table 4.9 JKR/SPJ. 3.Marshall method of mix design - Clause JKR/SPJ. 4.Test parameters of Marshall specimens - Table 4.10 JKR/SPJ. 5.Establish design aggregate grading and bitumen content with tolerances in Table 4.11 JKR/SPJ.

44 Mix Design Requirements 1.Grading of combined aggregates + filler - Table 4.8 JKR/SPJ. 2.Bitumen content - Table 4.9 JKR/SPJ. 3.Marshall method of mix design - Clause JKR/SPJ. 4.Test parameters of Marshall specimens - Table 4.10 JKR/SPJ. 5.Establish design aggregate grading and bitumen content with tolerances in Table 4.11 JKR/SPJ.

45 Table Design Bitumen Contents Class of MixNormal Range of Design Bitumen Content by Weight of Mix ACW 20 - WC % ACB 20 - BC % ACB 28 - BC %

46 Clause Asphaltic Concrete Mix Design 1.Prepare specimens for standard stability and flow tests as per AASHTO T 245 using 75 blows/face. 2.Determine bulk specific gravity of specimens as per AASHTO T Determine stability and flow values as per AASHTO T Voids analysis; VMA, VFB, VIM.

47 Mix Design Method MS 535 Specification for asphaltic concrete for road pavement and airfield runway by the Marshall test method. Asphalt Institute MS-2 Mix design methods for asphalt concrete.

48 Mix Design Requirements 1.Grading of combined aggregates + filler - Table 4.8 JKR/SPJ. 2.Bitumen content - Table 4.9 JKR/SPJ. 3.Marshall method of mix design - Clause JKR/SPJ. 4.Test parameters of Marshall specimens - Table 4.10 JKR/SPJ. 5.Establish design aggregate grading and bitumen content with tolerances in Table 4.11 JKR/SPJ.

49 Table Test Parameters For Asphaltic Concrete ParameterWCBC Stability S> 500 kg> 450 kg Flow F> 2.0 mm> 2.0 mm Stiffness S/F>250 kg/mm >225 kg/mm Air voids in mix % % VFB % %

50 Mix Design Requirements 1.Grading of combined aggregates + filler - Table 4.8 JKR/SPJ. 2.Bitumen content - Table 4.9 JKR/SPJ. 3.Marshall method of mix design - Clause JKR/SPJ. 4.Test parameters of Marshall specimens - Table 4.10 JKR/SPJ. 5.Establish design aggregate grading and bitumen content with tolerances in Table 4.11 JKR/SPJ.

51 Table Tolerances For Asphaltic Concrete Mixes ParameterPermissible Variation % by weight of total mix Bitumen content.+/- 0.2 % Fractions of combined aggregate passing 5.0 mm and larger sieves.+/- 5.0 % Fractions of combined aggregate passing 3.35 mm and 1.18 mm sieves. +/- 4.0 % Fractions of combined aggregate passing 425 µm and 150 µm sieves.+/- 3.0 % Fraction of combined aggregate passing 75 µm sieve.+/- 2.0 %

52 Trial Lay A minimum of 10 tons of each mix shall be placed in trial areas to demonstrate to the satisfaction of S.O. that the mixing, laying and compacting equipment conforms to the requirements of the specification, and that the proposed mixes are satisfactory. 1. Rollers. 2. Paver. 3. Trial site. 4. Tests on premix sample : Binder content & aggregate grading. Theoretical maximum specific gravity. Prepare Marshall specimens. Specific gravity, volumetric properties, Marshall stability and flow of Marshall specimens.

53 Trial Lay - Continue 5. Record temperatures of premix on lorry, at plant and site. 6. Record laying temperatures. 7. Record laying thickness. 8. Check texture of paved surface. 9. Record rolling temperatures. 10. Record rolling pattern. 11. Check texture and condition of compacted surface. 12. Record compacted thickness and density from core samples. 13. Check consistency in production. 14. Check at least one longitudinal joint.

54 Temperature Of Bitumen < 177 C (350 F)

55 Aggregate Stockpile Each aggregate shall be stored in a separate stockpile. Stockpiles of sand and other fine aggregates shall be kept dry using waterproof covers or other means.

56 Aggregate Grading Test Batch plant - 1 test per hot bin per day of production. Drum mix plant - 1 test per cold bin per day of production.

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59 Temperature < 163 C (325 F)

60 Sampling of premix

61 Sampling of Premix Sample quantity: > 20 mm (eg. ACB28) - minimum 24 kg. < 20 mm (eg. ACW20) - minimum 16 kg. Sampling from lorry: > 20 mm - take 4 increments. < 20 mm - take 3 increments. One increment approx. 7 kg (use size 2 square- mouth shovel). Scoop 100 mm below surface.

62 Testing of Premix 1 test per 200 tons of asphaltic concrete produced; * Bitumen content & grading. * Maximum specific gravity. * Preparation of Marshall specimens. * Bulk specific gravity of Marshall specimens. * Volumetric properties (VMA, VFB, VIM). * Marshall stability & flow.

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68 Density and Thickness Requirement 1. Required compacted density; Wearing Course : % Marshall density Binder Course : % Marshall density 2.The average thickness over any 100 metre length shall be not less than the required thickness. The minimum thickness at any point shall be not less than the required thickness minus 5 mm.

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71 Terima Kasih


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