cttp Testing Technician Refresher Info Math / Conversions Terminology ARDOT Specifications Standard Specifications Supplemental Specifications

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1 cttp Center for Training Transportation Professionals Testing Technician Refresher Info Math / Conversions Terminology Sampling Where to sample How to sample Reducing Samples What size is required Methods of reduction ARDOT Specifications Standard Specifications Supplemental Specifications 1

2 Test Methods % Passing # 200 by Washing Sieve Analysis Moisture Content Test Methods % Deleterious Matter % Crushed Particles Organic Impurities Specific Gravity Fine Aggregate Coarse Aggregate Absorption Written Exam 60 Questions Closed Book Exam 2 Hour Time Limit 70 % Overall Required to Pass Results Letter & Certification Performance Exam 6 Exam Stations Fine Agg SpG Coarse Agg SpG Washing Sieve Analysis Quartering / Splitting Organic Impurities 2

3 5 Year Certification To prevent expiration: Take online Basic Aggregates Certification Renewal course Pass final quiz after all online modules are complete Cost - $0 (none) Extends Basic Aggregates Certification 5 years If not completed prior to expiration date, other CTTP certifications will be suspended Soils, Hot-Mix Asphalt, Concrete, Concrete Strength Help? Mobile Accessible Basic Math for Transportation Covers symbols, order of operations, averaging, rounding, calculating percentages, conversions, using random numbers, and working with field stations. Basic Math for Aggregates Covers moisture content, % passing # 200 sieve by washing, sieve analysis, specific gravity, and percent absorption. If you need help with mathematical calculations, just ask. Your instructor will be happy to assist you. If you need further practice or assistance, please see our website for online training. 3

4 Grouping Parentheses ( ) Brackets [ ] Addition + Subtraction - Multiplication = = ( )( ) Division = =( ) Equal = Greater than > Less than < Greater than or equal to Less than or equal to Order of Operations (1st) (parentheses) or [brackets] Work from the inside out (2rd) exponents (2³)( 4) (3th) multiply & divide (4th) add & subtract What s the answer? + = a. 23 b = a. 23 b. 48 ( ) = a. 0.2 b. 5 4

5 Percent (%) a comparison of a portion to the whole % = % What % does the dark portion represent? Convert to a percent x 100% = 36.2% Convert to a decimal 5.3 % 5.3% / 100% = %= % % =. % = % Unit Conversions Weight / Mass 1 ton 2000 lb 1 lb g 1 kg 1000 g Convert 15 lb to grams. Convert 6804 g to pounds = =. 5

6 Unit Conversions Length 1 yard 3 ft 1 station 100 linear ft Volume = length x width x depth 1 yd³ 27 ft³ Area = length x width 1 yd² 9 ft² 1 yd 1 yd 1 yd 1 yd Oven Dried Dried to a constant mass at a temperature of 230 ± 9 F (110 ± 5 C) Air Dried Dried at a temperature of 140 F (60 C) Constant Mass The mass at which additional drying of the sample would result in less than an additional 0.1% loss in mass % = ( ) % W 1 = Weight 1 (wet) W 2 = Weight 2 (dry) 6

7 Terminology Sieve A rigid frame surrounding a wire mesh material with square openings Used to separate particles into individual sized fractions Sieve size is determined by the perpendicular distance between the parallel wires. U.S. (#) sieves Approximate number of openings in one linear inch U.S. (mm) U.S. (mm) U.S. (mm) # # ½ 37.5 # # # # ¾ 19.0 # # ½ 12.5 # # /8 9.5 # # ¼ 6.3 # #

8 % Passing The percentage of the total material which will pass through the sieve % Retained The percentage of the total material which will be retained on top of the sieve % Passing + % Retained 100 % Maximum Aggregate Size (MAS) ASTM C Smallest sieve opening through which the entire amount of aggregate is required to pass Smallest sieve opening size that 100 % of material passes What is the maximum aggregate size? 1 ¾ ½ Sieve Spec ¾ ½ - # ¾ 1 8

9 Nominal Maximum Aggregate Size (NMAS) ASTM C Smallest sieve opening through which the entire amount of aggregate is permitted to pass First sieve to retain any aggregate What is the nominal maximum aggregate size? 1 ¾ ½ Sieve Spec ¾ ½ - # ½ ¾ Coarse Aggregate Most of material is retained on the # 4 sieve Typically Clean Gravels / Crushed Stone Fine Aggregate Most of material passes the # 4 sieve Clean - Sands Dirty - Screenings Coarse Fine & Coarse Fine 9

10 Stations Used to mark distances along roadways 1 station = 100 linear feet 1 station 100 feet Station stations + 63 from start (50 x 100 ) from start Stations Stations may be added and subtracted to compute distances and locations Replace + sign with a decimal point when using a calculator Drop + sign for distance in feet Carry units over like ordinary Start : End What is the distance in feet between the stations? = = = 844 or 8.44 x 100 =

11 What is the distance in feet between stations and ? What is the above distance in stations? If you go 5,530 feet from station toward station , what station number do you end up at? Random Sampling Single Source Random numbers are used to determine Lot sample locations without bias Lot an isolated quantity of material from a single Sublots source Sublot a portion of a lot Sample a small portion of a lot or sublot which represents that lot or Samples sublot 11

12 ARDOT Base Aggregate Lot 4000 tons ARDOT Sublot 1000 tons Contractor Lot 1 S 1 S 2 S 3 S What is the test tonnage for Sublot 4? Assume ARDOT base aggregate lot and sublot sizes. RN = 0.66 (0.66)(1000) = Lot 1 Lot 2 Lot 3 S 1 S 2 S 3 S

13 What tonnage does Lot 3, Sublot 4 begin at? Assume ARDOT base aggregate lot and sublot sizes. 2(4000) + 3(1000) = 11, Lot 1 Lot 2 Lot 3 S 1 S 2 S 3 S What is the total sample tonnage location for Lot 3, Sublot 4? RN = 0.66 (0.66)(1000) = 660 2(4000) + 3(1000) = 11,000 Total Sample Tonnage = ,000 = 11, Lot 1 Lot 2 Lot 3 S 1 S 2 S 3 S

14 What is the total sample tonnage location for Lot 6, Sublot 2 of an ARDOT base haul? Use a random number of Sublot 3 starts at station and ends at station The width of the material is 16 ft. Find a random sample location using the random numbers of 0.64 and S 3 S 4 14

15 RN 0.64 Station Location Find the distance between stations Sta Sta. = 4.10 Sta. Multiply distance by random number (0.64)(4.10) = Sta. = 2.62 Sta. Add test distance to starting station Sta Sta. = Sta. = Station ft = Sta ft = Sta. RN 0.30 Offset Multiply width by random number (0.30)(16 ft) = 4.8 ft = 5 ft off edge Determine if off left or right edge As stations increase in number, left edge is to your left and the right edge is to your right Left edge 5 off left edge Right edge

16 Find the random sample location using a RN = 0.41 for the station number, and a RN = 0.82 for the offset Size Large enough to hold the minimum field sample size required Type Sealable Durable Leak-proof Unlined open weave mesh bags should not be used Labels Source, material, and date as a minimum Tests required Sampled by 5 gal 55 lbs (25 kg) 16

17 Sampling Methods for removing a sample of material, in such a way that the sample is representative of the bulk material Representative Sample Material which is proportional in size characteristics and exhibits the same physical properties when tested Segregation Separation of materials into an unblended state 17

18 Samples to be tested for quality should be obtained from the finished product Aggregate Size A D75/D75M - 14 TABLE 1 Minimum Size of Field Samples Field Sample Mass, min. kg B [lb] Field Sample Volume, min. L [gal] Fine Aggregate 2.36 mm [No. 8] 10 [22] 8 [2] 4.75 mm [No. 4] 10 [22] 8 [2] Coarse Aggregate 9.5 mm [⅜ in.] 10 [22] 8 [2] 12.5 mm [½ in.] 15 [35] 12 [3] 19.0 mm [¾ in.] 25 [55] 20 [5] 25.0 mm [1 in.] 50 [110] 40 [10] 37.5 mm [1½ in.] 75 [165] 60 [15] 50 mm [2 in.] 100 [220] 80 [21] 63 mm [2½ in.] 125 [275] 100 [26] 75 mm [3 in.] 150 [330] 120 [32] 90 mm [3 ½ in.] 175 [385] 140 [37] A For processed aggregates, use the nominal maximum size indicated by the appropriate specification or description. If the specification or description does not indicate a nominal maximum size (for example, a sieve indicating 90 to 100 % passing), use the maximum size (that sieve indicating 100 % passing). B For combined coarse and fine aggregates (for example, base or subbase aggregate), the minimum weight shall be coarse aggregate minimum mass plus 10 kg. Use power equipment Check for cleanliness Samples are taken from a working face 18

19 Pull loader buckets of material from at least 3 different areas and elevations of stockpile Mix material Back-drag pile Obtain samples (3) Diagonally AHTD (4) Quadrants - AASHTO Manual Sampling Insert board vertically above sampling area Excavate segregated material and discard Sample from three locations of bench Sample from the top third, middle, and bottom third of the pile Combine all samples 19

20 Fine aggregate only Remove outer layer Insert sample tube at least 3 above bottom of pile Sample tubes should be at least 1 1/4 in diameter and 6 feet long One end may be cut to a 45 angle Extract sample Sample from at least 5 different locations Stop the belt Insert template(s) Gather all material within the template Use brush to collect fines Sample from a minimum of 3 different locations along the belt Combine samples 20

21 Pass collector unit through entire stream Collect entire crosssection of stream Avoid overfilling Sample from a minimum of 3 different locations Combine samples Power Equipment Sample from multiple elevations and locations Manual Excavate 3 trenches 1 wide x 1 deep Collect 3 increments from each trench with a shovel Combine all samples Sample tubes may be used vertically inside trenches for fine aggregate samples 21

22 Collect equal increments from at least 3 random locations within the unit being sampled Sample the full depth of material Exclude all underlying materials Use templates to aid in securing equal increment weights Combine samples Methods used to reduce a field sample to a smaller size for testing purposes Proper techniques help preserve the characteristics of the field sample and minimizes variations in testing results Maintain physical characteristics Size distribution Blending of materials 22

23 Which of the reduced samples would be representative of the field sample? A. B. C. Test sample size Specified by the individual test method What is the minimum test sample size for a sieve analysis conducted using AASHTO T 27 if the NMAS of the sample is 1 inch? 23

24 Assume your field sample weighs 50,000 grams. How many times would you need to split a sample to obtain a test sample size of 10,000 g? 2 50,000 25, ,000 12, , Too Small Method used depends on: Aggregate Size (Coarse, Fine, or Mixed) Moisture Content (> SSD, SSD, < SSD) SSD Saturated Surface Dry < SSD Surface dry Pores not saturated (fines won t clump together) SSD Surface dry Pores saturated (fines won t clump together) > SSD Surface wet Pores Saturated (fines will clump together) 24

25 Coarse Agg. Splitter May be used for: Coarse Agg - Any MC Preferred method Mixed Agg - SSD Fine Agg - SSD Chute Openings At least 8 openings Same number per side 50 % > largest rock Fine Agg. Splitter May be used for: Fine Agg - SSD 100 % must pass 3/8 Chute Openings At least 12 openings Same number per side 50 % > largest rock Maximum width 3/4 Feeder Pan Straight-sided Width equal to or slightly less than total chute assembly width 25

26 Place sample in hopper or straightsided pan Distribute evenly from side to side Use an even flow to feed sample to chutes Avoid restricted flow Avoid loss of material Check split samples If an uneven split occurs, recombine split halves and redo Discard one of the split halves and retain the other Repeat process until desired sample size is achieved Do both sides have the same ratio of fine to coarse aggregate? 26

27 May be used for: Coarse Agg - All Mixed Agg - All Fine Agg - > SSD Sweep smooth floor to remove any dust or foreign material A canvas tarp may be used for uneven floor surfaces Place sample on clean quartering area Mix aggregate by turning pile over a min. of 3 times This Photo by Flatten pile so that the diameter is 4 to 8 times the thickness of the pile Sweep loose material back to pile Divide pile into four equal quarters

28 Check split Remix if necessary Combine diagonally opposite quadrants Gather all fines Set aside ½ sample Repeat process with remaining ½ sample until desired size is achieved May be used for: Fine Agg - > SSD Place original sample on clean surface Mix aggregate by turning pile over a min. of 3 times 28

29 Flatten pile to uniform thickness and diameter (optional) Select a minimum of 5 increments of material Combine increments General Lab Practices Check calibration Yearly Check level Check for interference Platform Weigh below Drafts or currents Zero scales Tare button Place items ready to be weighed gently on platform Lab Scales Do not exceed the scale s capacity! 29

30 ARDOT specification limits are considered absolute limits! Observed or calculated values are not rounded for determination of compliance Compared directly with the limit Average values are rounded to same # of significant digits Any deviation outside limits is non-compliance Failing test Determines the % of material finer than the # 200 sieve by washing Materials removed during washing Fine aggregates Clay particles Water soluble materials If the sample is to be sieved after washing under AASHTO T27, then the test sample size is determined by AASHTO T27 Washing before sieving provides a better determination of the % passing the # 200 sieve than dry sieving alone 30

31 What minimum size sample is required for aggregate with a NMAS of 3/8 to determine % decant loss for an ARDOT project? Method A Uses wash water only Suitable for most aggregates Use Method A if Method B is not specified or requested by the agency Method B Uses a wetting agent to disperse the fines Liquid dishwashing detergent Use this method if specified or requested by the agency Typically used for aggregates with clay coatings or those extracted from bituminous mixtures 31

32 Equipment Scales Readable to at least 0.1% of test sample mass or better Oven 230 ± 9 F (110 ± 5 C) Sieves (ASTM E11) # 200 Wash Sieve #8 - #16 Cover Sieve Optional Equipment Mechanical Washer Mechanical washers are allowed provided that the results are consistent with hand washing Degradation of the sample may occur if used improperly 32

33 Preparation Obtain representative field sample Mix and reduce field sample to test size Dry sample at 230 ± 9 F to a constant mass Dry samples overnight (15-16 hours) or weigh at hourly intervals until there is no change in weight Cool, weigh sample, and record dry weight (D B ) Check to see if sample meets minimum mass Cover the sample with water and agitate Rinse hand or tool before removing from pan 33

34 Pour wash water over nested sieves Avoid transferring aggregate to cover sieve Cover sample again with water, agitate, and decant wash water Repeat process until wash water is clear Transfer coarse material retained on cover sieve into sample container Wash fines into wash sieve or sample container Flush all material retained on wash sieve into sample container Check sieve for cleanliness 34

35 Dry sample to a constant mass Cool to room temperature Record dry weight (D A ) Calculate % Passing #200 Sieve Decant % # = % Report 0.1 % if < 10 % D B = Dry Wt. (before wash) 1 % if 10 % D A = Dry Wt. (after wash) Determine the % passing the #200 sieve Dry Wt (Before Wash) Dry Wt (After Wash) g g = Weight of Material Washed Out of Sample x 100 = 7.32 = 7.3 % Report : 1 % if 10 % 0.1 % if < 10 % 35

36 Determine the % passing the #200 sieve and report your results Dry Wt (Before Wash) Dry Wt (After Wash) g g % # = % Determines the particle size distribution of fine and coarse aggregates by dry sieving Used to determine compliance with specifications and production controls Grading affects the strength, stability, workability, and the volumetric properties of aggregates 36

37 Equipment Scales Readable to at least 0.1% of test sample mass or better Oven 230 ± 9 F (110 ± 5 C) Sieves (ASTM E11) Stack depends on specifications Shaker (optional) Must meet required sieving accuracy of hand sieving in 10 minutes or less to prevent degradation of the sample Shaker time must be checked yearly Preparation Collect representative field sample Size should meet AASHTO T2 or be 4 times the test sample size Mix and reduce field sample Dry test sample to a constant mass Hotplates & burners are allowed if no fracturing/chemical breakdown of aggregate occurs Cool and record dry weight Check to see if sample meets minimum mass 37

38 What is the minimum mass required for an aggregate with a NMAS of #4? What is the minimum mass required for an aggregate with a NMAS of ¾? PREVENT OVERLOADED SIEVES! Overloaded sieves prevent some of the aggregate particles from reaching the openings Sieving adequacy required is not typically met since additional material will pass through the sieve if given a chance Produces a coarser and inaccurate sieve analysis result 38

39 Coarse Agg. Sieves Opening sizes # 4 > 1 Layer Overloaded Fine Agg. Sieves Opening sizes < # 4 Retained mass shall not exceed 7 kg/m² 1 Layer OK Sieve Max. Mass (g) 200 g 320 g 469 g Prevention Methods (1) Insert additional sieves ¾ #4 #8 Overloaded #4 ¾ ½ ⅜ #4 #8 Each additional sieve catches some of the material which would have been caught on the # 4 screen originally This lessens the total amount of material on the # 4 sieve, preventing the overloading of the sieve 39

40 Prevention Methods (2) Use larger sieves 8 Diameter 12 Diameter Increases the sieving area available to the rock ¾ ½ #4 ¾ ½ This spreads the rock particles apart on the screen lessening the chances of overloading #4 Prevention Methods (3) Split sample into smaller portions for sieving Sieve each portion individually Combine weights before computation ¾ ⅜ ½ #4 Pan P1 Test Sample P2 Sieve Wt Ret (P1) Wt Ret (P2) Total Wt Ret ¾ ½ / # Pan

41 Nest sieves in order of decreasing opening size from top to bottom Check cleanliness and condition of sieves Add sample to stack Take care to prevent loss of material Prevent overloading Agitate sieves Hand Sieving Tap side of sieve sharply with heel of hand 150 strokes/minute rotating 1/6 th turn every 25 strokes Mechanical Shaker Shake for calibrated time or verify after shaking by hand sieving Conformance Shake until 0.5% by mass of the total sample passes during 1 minute of continuous hand sieving Do not force particles to pass through openings 41

42 Before emptying sieve: Check undersized openings for trapped particles Remove trapped particles and determine proper placement Check sieves for overloading Hand sieve if overloaded Empty sieve Clean sieves thoroughly Record mass retained General Lab Practices Sieves Do not force rocks through any opening Sieves Rocks bound in undersized openings should be removed and placed where they belong Use care when removing bound rocks to prevent damage Use appropriate brushes to clean sieves when emptying Do not overload sieve screen! Use only a paintbrush to clean # 200 sieve 42

43 Cum. Wt. Retained Add individual weights Sieve Ind. Wt. Retained Cum. Wt. Retained 3/ # # # # Pan Individual Weights Vary and go up and down in value from sieve to sieve with no pattern Cumulative Weights Start at zero and progressively increase Cumulative weights should never exceed original dry weight % Retained Starts at 0% and progresses toward 100% Report to nearest 0.1% % =... % D B = dry weight before washing Dry Wt (D B ) Dry Wt (D A ) Sieve Cum. Wt. Retained 3/8 0.0 # # # # g g % Retained (302.5 / 928.5) x 100% = 32.6% 43

44 % Passing Starts at 100% and progresses toward 0% Report to nearest 0.1% Sieve % Retained 3/8 0.0 # # # # % Passing %. = % % 100% % = 67.4 % Reported % Passing Round values for calculated % passing Report all sieves except the # 200 to nearest 1% Sieve % Passing 3/ # # # # Reported % Passing Report the # 200 sieve 1% if 10% 0.1% if < 10% How would you report a value of 11.2 % for the # 200 sieve? 11 44

45 Acceptance check is a required calculation used to determine if a sieve analysis may be used and reported for acceptance purposes Determines the error produced due to the sieving process Acceptance Check (AC) = ( ) Out = Cum. Wt. Ret. in Pan In = After Wash Dry Weight Tolerance = ± 0.3% Calculate the acceptance check Dry Wt. (D B ) g Dry Wt. (D A ) g Sieve Cum. Wt. Retained ½ 0.0 # # # Pan In Out = = = ( ) (.. ).. =. %. Tolerance = ± 0.3% 45

46 Used to control the amount of minus #200 found in base rock ARDOT Specification Section 303 SS-Errata DR 0.75 for all classes of base aggregate Dust Ratio = % # % # Use only the reported % passing values for calculation Report Dust Ratio to nearest 0.01 Find the dust ratio = = % # % #. = Sieve Calc. % Pass Reported % Passing 3/ # # # #

47 An index of the particle size distribution Used in concrete specifications to control fluctuations in grading ARDOT Section 501 FM variation > 20 points, requires a new concrete mix design Fineness Modulus =. %. Sieves used to compute: # 100, # 50, # 30, # 16,# 8, # 4, 3/8, ¾, 1 ½, 3, Report FM to nearest 0.01 Find the FM Locate cumulative % retained for sieves # 100, # 50, # 30, # 16,# 8, # 4, 3/8, ¾, 1 ½, 3, Add values Divide total by 100 FM = ( ) / 100 FM = / 100 FM = Sieve Cum % Ret ¾ 0.0 ½ / # # # # # # #

48 Crushed particles have angular faces which create an interlocking force between particles Interlocking particles increase the shear strength and load bearing capacity of the material Uncrushed aggregates such as natural gravels, have smooth, rounded faces which do not interlock Base rock specifications limit the amount of uncrushed rock in order to increase strength and stability 48

49 Equipment Scales readable to 0.1% of sample mass Heat Source and # 4 Sieve Preparation Obtain a representative field sample Mix and reduce sample Dry sample to a constant mass (230 ± 9 F) and cool Sieve sample over the # 4 sieve Retain the coarse aggregate for testing Record dry weight of test sample Check to see if sample meets minimum mass Based on the sieve analysis, what size test sample would be required? Particle Sizes Sample Weight (g) # 4 to ½ 500 g # 4 to ¾ 1000 g # 4 to 1 ½ 1500 g Sieve % Retained % Passing 1½ ¾ / # # # #

50 Separate particles into two groups Crushed Faces No Crushed Faces Crushed Record weight of material with crushed faces Calculate % Crushed %. =.. Uncrushed Report to nearest 0.1% Determine the % of crushed material in the sample Sample Wt (+ #4) g Wt of Crushed g %. = %. = %.. % =. 86.4% 50

51 Determine the reported % of crushed material in the sample Sample Wt (+ #4) g Wt of Crushed g %. = % Determines the % of deleterious matter in aggregates Deleterious - anything which may be harmful to the finished product Concrete Asphalt Base Aggregates Interferes with the bonding between the aggregate and the cementing material Creates a weak zone in the finished product Deleterious Clay Lumps Shale / Slate Friable Particles 51

52 Clay Lumps Lumps of clay or any soil/aggregate material adhering together Do not break clay lumps apart during sieving Clay Lump Shale / Slate Laminated layers of compressed clay, silt, or mud Leaves a streak on a streak plate, flakes Shale has a waxy feel Classify as shale if 50% or more of the aggregate is shale Shale Slate 52

53 Friable Particles Any particles which can be broken into finer particles with your fingers Soft Aggregates Organics Coal Lignite Equipment Scales readable to 0.1% of sample mass Heat Source and # 4 Sieve Non-glazed streak plate or mortar bowl Preparation Obtain a representative field sample Mix and reduce sample Dry sample to a constant mass (230 ± 9 F) and cool Sieve sample over the # 4 sieve Retain the coarse aggregate for testing Record dry weight of test sample Check to see if sample meets minimum mass 53

54 Separate sample into groups Record the weight of the deleterious material Calculate %. =. %. Report to nearest 0.1 % Determine the reported % total deleterious in the sample Total Sample Weight Weight of Deleterious g g %. = %. =.. %.. % =. % 3.4% 54

55 Determine the reported % clay lumps and % total deleterious in the sample Total Sample Weight Weight of Clay Lumps Weight of Organic Mat g 38.7 g 63.2 g %. =.. % Determines if injurious organic compounds are present in the fine aggregates used to make hydraulic cement mortar or concrete Test colors darker than the standard color indicate that injurious organic compounds may be present Perform additional testing before using AASHTO T 71 Effect of Organic Impurities on the Strength of Mortar 55

56 Equipment Colorless glass bottle w/ cap O.D. Graduations Reagent 3% NaOH Solution Dissolve 3 parts NaOH in 97 parts water Color Plate Organic Plate #3 Gardner Color #11 or Color Solution Less precise method than using color plates Must be made fresh with 2 hours of comparison Preparation Collect Field Sample Mix and reduce to 450 g (1 lb) Air dry only if required by specifications Air Dry 140 F (60 C) 130 ml Fill bottle to 130 ml (4 ½ oz) level with aggregate 56

57 Add 3% NaOH solution until volume is 200 ml (7 oz) 200 ml Stopper bottle shake Let stand 24 hours Compare liquid color to the standard color Record the plate # nearest the liquid color If using a standard color solution, record if lighter, darker or of equal color 57

58 Standard Color Solution Dissolve g of Potassium dichromate (K 2 Cr 2 O 7 ) In 100 ml of Sulfuric acid (G = 1.84) Use heat if necessary Must be made fresh and within 2 hours of comparison Fill empty bottle to 75 ml (2½ oz) level with color solution and compare colors Classroom Demo Used to determine the % of evaporable moisture in aggregates Preserve moisture in field samples by using sealable airtight containers Equipment Scales Readable to nearest 0.1% of sample mass or better Heat Source Oven / Hot Plates Drying Container Depth of sample in container must be 1/5 th of the least lateral dimension 58

59 Caution - rapid superheating may cause the aggregate to explode Stir aggregate while drying when using a heat source other than an oven Accelerates drying Prevents localized heating Preparation Obtain a representative field sample Protect sample from moisture loss Mix and reduce field sample to test size Weigh and record the wet weight of aggregate Check to see if sample meets minimum mass requirements (AHTD and AASHTO vary greatly in the size of samples required 59

60 Dry sample to a constant mass and cool AHTD allows drying overnight hours = ( ) % Weigh and record dry weight of aggregate Calculate Report MC to nearest 0.1% W = wet weight of aggregate D = dry weight of aggregate Find the moisture content of the sample Wet Weight of Agg Dry Weight of Agg % = ( ) g g % % = (.. ) % =. %. 2.8 % 60

61 Find the moisture content of the sample Wet Weight of Agg Dry Weight of Agg g g % = ( ) % To determine the % of surface moisture present in an aggregate sample: 1. Find the total moisture content of the sample 2. Find the aggregate s absorption Use AASHTO T84 or AASHTO T85 3. Subtract the absorption from the total moisture content Moisture Content 2.8% Absorption 1.2% Surface Moisture 1.6% 2.8% -1.2% 1.6% 61

62 Specific Gravity Archimedes Principle The ratio of the mass of an object in air to the mass of an equal volume of water G Used to determine the specific gravity (relative density) and absorption of coarse aggregates Do not use with lightweight aggregates Pores spaces may not be completely filled within the allowed timed of hours Absorption The increase in mass of an aggregate due to the mass of water absorbed into the pores of the rock 62

63 Equipment # 4 Sieve Scales M231 Class G 5 (1 g) Water Tank Equipped with overflow Wire Basket # 6 or finer mesh Drying Apparatus 230 ± 9 F (110 ± 5 C) Preparation Obtain a representative field sample Mix and reduce sample Dry sample to a constant mass (230 F / 110 C) Values for absorption and bulk specific gravity (SSD) may be significantly higher for aggregate not dried before soaking Cool sample at room temperature (1-3 hours) Sieve sample over # 4 sieve (retain + #4) Check to see if sample meets minimum mass Wash sample to remove dust Completely cover sample with water for hours 63

64 Adjust temperature of water bath to 73.4 ± 3 F (23.0 ± 1.7 C) Fill water bath to overflowing and allow water level to stabilize Unplug water pumps Check weigh below apparatus for interference Pour excess water off test sample Tare out empty bowl on top of scales Bring sample to SSD Dry aggregate surface with absorbent towel Weigh sample and record the SSD weight of aggregate 64

65 Remove bowl from scales Place wire basket under water Agitate basket to eliminate trapped air Allow water level to stabilize Zero out scales Place sample in basket and suspend in water bath Agitate basket to eliminate trapped air Allow water level to stabilize Record the submerged weight of the aggregate 65

66 Empty basket into a clean container Remove all fine particles from basket Dry to a constant mass 230 F / 110 C Cool sample (1 3 hrs.) Weigh sample and record the dry weight of aggregate Calculate Equipment # 4 Sieve Scales M231 Class 2 (0.1 g) Pycnometer 500 ml Cone Mold & Tamper Drying Apparatus 230 ± 9 F (110 ± 5 C) Miscellaneous Hair dryer, funnel, spoon, alcohol 66

67 Preparation Obtain a representative field sample Mix and reduce sample Dry sample to a constant mass (230 F / 110 C) and cool Sieve sample over # 4 sieve (retain minus #4) Check to see if sample meets minimum mass 1000 g (1 kg) Soak sample in water for hours Totally immerse or add a minimum of 6% moisture 0.06 x test weight Protect from evaporation Calibrate pycnometer Fill with water to calibration mark 73.4 ± 3 F Read bottom of meniscus Weigh and record the weight of the Pyc + Water 67

68 Prepare pycnometer for introduction of sample Empty water until pycnometer is half full Place pycnometer with funnel on scale and zero out scales Perform cone test to check for moisture condition Aggregate must be on the wet side of SSD when beginning test If too dry : Add water, cover Let stand for 30 min. 68

69 Cone Test Fill cone to overflowing Tamp 25 times from a height of 0.2 (5mm) Clean aggregate from base of cone Lift cone vertically 0.2 Wet Aggregate Maintains Shape Dry Aggregate Flattens to Cone Shape SSD Aggregate Slumps Slightly Materials with a high % of fines may slump only on one side of the mold Use alternative methods of determining SSD Bring sample to SSD Dry sample with warm, gentle current of air Perform cone test to check for SSD condition When material is at SSD condition, immediately proceed with test procedure Additional drying of aggregate will result in error 69

70 Add 500 ± 10 g of SSD aggregate to pycnometer Record SSD weight If using a companion sample to obtain dry weight, immediately obtain companion sample ± 0.2 g of SSD sample Place companion sample in oven to dry Record all weights to 0.1 g! Fill pyc with water until 90 % full Just into or slightly below neck Agitate pycnometer to remove air (15-20 min) Mechanical agitation allowed Must match manual agitation Vacuum is not allowed 70

71 Adjust temperature to 73.4 ±3 F (23 ±1.7 C) Fill pycnometer with water to calibration mark Eliminate foam Dry inside neck and outside of pycnometer Record weight of pyc + sample + water If a companion sample was not used, completely empty the pycnometer and dry aggregate Remove sample from oven Cool for 1 ± 0.5 hours at room temperature Companion sample Pycnometer sample Record oven dry weight of aggregate Calculate 71

72 Oven Dry The pores spaces contain no water and the surface is dry Saturated (SAT) The pores spaces are filled with water and free water is present on the surface Sat. Surface Dry (SSD) The spaces are filled with water but the surface is dry What do you think the specific gravity of rock is? < 1 sinks > 1 floats AR Gsb stone bulk Type of specific gravity is based on the rock s moisture condition and volume being considered Apparent (Gsa) Relative density of solid particles only Bulk (Gsb) Takes into account pore spaces accessible to water Bulk SSD (Gsb ssd ) Takes into account pore spaces accessible to water 72

73 Apparent (Gsa) = ( ) A = Dry weight C = Submerged weight Report to nearest Used in soils Used in asphalt Bulk (Gsb) = ( ) A = Dry weight B = SSD weight C = Submerged weight Report to nearest Used in asphalt 73

74 Bulk ssd (Gsb ssd ) = ( ) B = SSD weight C = Submerged weight Report to nearest Used in concrete Absorption Moisture content of the aggregate at SSD condition hours soak time % = Report to nearest 0.1 % ( ) % A = Dry weight B = SSD weight 74

75 Dry Wt g A Find the specific gravities SSD Wt g B and absorption of the Sub Wt g C coarse aggregate. = = = % = =.. = =. (.. ). ( ) =.. = =. (.. ). ( ) =.. = =. (.. ). ( ) = (.. ).. = = % AASHTO (Fine) Gsa = A / (B + A C) Gsb = A / (B + S C) Gsb ssd = S / (B + S C) Abs = [(S A) / A] x 100% A = Dry mass B = Pyc + Water C = Pyc + Water + Sample S = SSD mass AASHTO (Coarse) Gsa = A / (A C) Gsb = A / (B C) Gsb ssd = B / (B C) Abs = [(B A) / A] x 100% A = Dry mass B = SSD mass C = Submerged mass = + + ( + ) 75

76 Find the specific gravities and absorption of the fine aggregate A B C Dry Wt SSD Wt Pyc + Water Pyc + W + S g g g g Determine A, B, C, and/or S = =.. =. Calculate using appropriate formulas A S B C = = Using Coarse Agg. Formulas = % = Dry Wt SSD Wt Sub Wt g g g =.. = =. (.. ). ( ) =.. = =. (.. ). ( ) =.. = =. (.. ). ( ) = A B C.. = % 76

77 Using Fine Agg. Formulas Dry Wt SSD Wt Pyc + Water Pyc + W + S g g g g A S B C = + =. (. +.. ) = ( + ) =. (. +.. ) = ( + ) =. (. +.. ) % = ( ) =.... = =.. =.. =. =... = =.. = % Combines the specific gravities and absorptions of individual aggregates or sizes of aggregates Blends of multiple stockpiles Blends of different size fractions of the same aggregate 77

78 Combined SpG (G comb ) = + + P = The percentage of total sample which the aggregate or size fraction constitutes G = The specific gravity of the individual aggregate or size fraction Agg 1 39 % Find the combined Agg 2 40 % apparent specific Agg 3 22 % gravity of the blend = P Gsa 100 % = =. =

79 Agg 1 72 % Find the combined Agg 2 28 % bulk specific = P Gsb + + gravity of the blend Combined Absorption (A comb ) = + + P = The percent of the total sample of which the aggregate or size fraction constitutes A = The absorption of the individual aggregate or size fraction 79

80 Agg 1 38 % 1.3 % Find the combined Agg 2 40 % 1.5 % absorption of the Agg 3 22 % 0.8 % blend = P 100 % A (. ) (. ) (. ) = + + =. =. 1.3 % P A Agg 1 65 % 0.8 % Find the combined Agg 2 35 % 1.2 % absorption of the blend =

81 Sieve % Passing 3/ /2 88 3/8 80 # 4 70 # 8 60 # # # # # % Retained Coarse Agg. Plus #4 70 % Passing Fine Agg. Minus #4 Sieve % Passing 3/ /2 92 3/8 85 # 4 72 # 8 58 # # # # # What is the % of the material which passes the #4 sieve? 72 % What is the % of the material which is retained on the # 4 sieve? = 28 % 81

82 Sieve % Passing 3/ /2 84 3/8 72 # 4 60 # 8 50 # # # # # What is the % of the fine aggregate? 60 % What is the % of the coarse aggregate? = 40 % Sieve % Passing 3/ /2 75 3/8 62 # 4 47 # 8 40 # # # # # What is the % of the plus # 4 material? = 53 % What is the % of the minus # 4 material? 47 % 82

83 Sieve % Passing 3/ /2 84 3/8 72 # 4 62 # 8 50 # # # # # Find the bulk specific gravity for the stockpile P1 = 38 P2 = 62 = Gsb Coarse Gsb Fine = = G1 G Sieve % Passing /4 95 1/2 70 3/8 60 # 4 35 # 8 20 # # # 50 7 # # Find the apparent specific gravity for the stockpile Gsa Coarse Gsa Fine =

84 Sieve % Passing 3/ /2 84 3/8 72 # 4 62 # 8 50 # # # Find the absorption for the stockpile P1 = 38 P2 = 62 Abs Coarse 1.2 % Abs Fine 2.4 % = ( )+( )+ = (. ) + (. ) A1 A2 # % # = Sieve % Passing /4 95 1/2 70 3/8 60 # 4 35 # 8 20 # # # 50 7 # # Find the absorption for the stockpile Abs Coarse 0.5% Abs Fine 2.1% =

85 Chert Limestone Dolomite Syenite Gravel Sandstone Aggregate any combination of sand, gravel, or crushed stone Stone Naturally occurring solid formations of rock Crushed Stone Sand & Gravel Loose natural deposits of rock (usually found along stream channels and riverbeds) 85

86 Crusher Run Material Rock is mechanically broken into smaller pieces by passing it through a series of crushing units. The crushed rock is separated into useable fractions by a large screening plant and then stored in stockpiles. 1. Standard Specification (2014 Edition) Material specifications, design requirements, field tolerances, test procedures, quality control, pay 2. Supplemental Specifications (Errata) Changes to standard specifications which pertains to all jobs let after the date of publication 3. Job Plans Design and construction information, quantities 4. Special Provisions Modifications or additions to standard specifications which pertain only to the job it was published for Website : 86

87 Select Materials foundation courses for base aggregate material usually consisting of sandy soils, or sandy soil mixed with stone or gravel Section 302 of Standard Specifications Base Aggregates surface courses (gravel roads) and foundation courses for pavements consisting of crushed stone, gravel, and/or steel slag Section 303 of Standard Specifications Section % max. total % deleterious matter Specifications are considered absolute limits! AGGREGATE BASE COURSE GRADING (AASHTO T 11 AND T 27) AND CRUSHING REQUIREMENTS (AHTD TEST METHOD 304) PERCENT PASSING SIEVE (mm) CLASS 1 CLASS 2 CLASS 3 CLASS 4 CLASS 5 CLASS 6 CLASS 7 CLASS 8 3" 75.0 mm " 50.0 mm ½" 37.5 mm " 25.0 mm /4" 19.0 mm /8" 9.5 mm # mm # mm # mm # mm MAX PLASTICITY INDEX (MINUS # 40 MATERIAL) MINIMUM % CRUSHED (RETAINED ON # 4) 15 MINIMUM PERCENT CRUSHER RUN MATERIAL

88 Sieve % Passing 3/8 100 # 4 97 # 8 80 # # # # # Is this a fine aggregate or coarse aggregate? Fine The majority of the material passes the # 4 sieve Does this meet the ARDOT gradation specifications for fine concrete aggregate? Yes What about decant? Yes Does the sample meet ARDOT gradation and D.R. specifications for Class 7 Base? Gradation? Meets all required specification ranges Dust Ratio? Requires D.R DR = 10/13 = 0.77 No Sieve % Passing 1 ½ ¾ 71 3/8 50 # 4 28 # # # AHTD Spec

89 Sieve % Passing / /4 92 1/2 80 3/8 46 # 4 28 # # # Based on gradation only, which class of ARDOT base aggregate does the stockpile represent? ¾ eliminates CL 6 & 7 # 4 eliminates CL 1 5 Meets all gradation requirements for Class 8 Base 89