Mineral Aggregate Properties Introduction In this lab module several characteristics of aggregates are determined. Tests will be conducted on both coarse and fine aggregates. The results of some of these tests will be used in the subsequent lab modules for the Portland cement concrete and Superpave hot mix asphalt (HMA) mix design experiments. Safety Considerations This lab experiment procedure involves working with aggregates of varying sizes and at temperatures of up to about 250 F. Some lifting and shoveling may be required. Also, there is risk that some of the materials could stain your clothing, so plan to wear appropriate clothing. In addition to the standard lab safety requirements, you are required to wear the following safety items while participating in the preparation or: safety glasses long pants shoes that completely cover your feet You will also be provided with heat-resistant gloves, a lab coat as needed for certain operations in the lab. Aggregate Materials The aggregate tested and where they will be used in this course is shown in Table A below. Table A. Aggregates used. Gradation End use Coarse Fine CA-11 CA-6 FA-01 FA-20 MF* Portland cement concrete - - - Hot-mix asphalt - *Mineral filler 2003-2005 Department of Civil Engineering, Southern Illinois University Edwardsville 12/22/2011 Page 1 of 19
The aggregates tested and where they will be used in this course are shown in Table B below. The data tables included in this lab procedure packet are also shown. Table B. Aggregate tests to be performed. Gradation Tests to be Performed Coarse Fine CA-11 CA-6 FA-01 FA-20 MF** Specific Gravity and Absorption Table 1 Table 2 Table 9 Table 10 - Sieve Analysis Table 3 Table 4 Table 11 Table 12 - Bulk Unit Weight Table 5 - - - - Natural Moisture Content Table 6 Table 7 Table 13 Table 14 - Washed Sieve Analysis - - Table 8 Table 15 - ** Properties for MF will be provided I. COARSE AGGREGATE I. (A) Specific Gravity and Absorption of Coarse Aggregate 1. Objective To acquaint the student with specific gravity and absorption tests on coarse aggregate. Values obtained from these tests will be used later in the course in the design of Portland cement concrete and asphalt mixes. 2. Preparatory Reading ASTM C 127; AASHTO T85; Specific Gravity and Absorption of Coarse Aggregates 3. Generalized Procedure A 4000-gram sample of coarse aggregate has been soaking in water for 24 hours to saturate the sample. 1) Dry the sample (with towels) to SSD condition. 2) Weigh the SSD sample in air (B). 3) Immerse the sample in water and weigh (C), being careful not to lose any of the sample. 4) Put the sample back in the bowl and place it in the oven. 5) Weigh the OD sample in air the next morning (A). Page 2 of 19
6) Record all weights to the nearest one-gram. 7) Don t forget to allow for tare weights. 8) Make calculations and compute the bulk specific gravity (SSD) before leaving the lab. I. (B) Dry Sieve Analysis of Coarse Aggregate 1. Objective To acquaint the student with sieve analyses tests for coarse aggregates. Values obtained from tests will be used later in the course in the design of Portland cement concrete and asphalt mixes. 2. Preparatory Reading ASTM C 136; AASHTO T27; Sieve Analysis of Coarse and Fine Aggregates ASTM C 33; AASHTO M80; Coarse Aggregate for PCC Specification. 3. Generalized Procedure A sample of coarse aggregate has been dried overnight in an oven to obtain a moisturefree sample. 1) Collect a 5000-gram sample of CA-11 and 2000-gram sample of CA-6. 2) Use the large rectangular shaker and sieves. Select the sieves for the large shaker depending on the top particle size: a) For CA-11, use the 1", ¾", ½", #4, #8 sieves and pan. b) For CA-6, use the ¾", 3 / 8 ", #4, #8, #16, #30 and #200 sieves and pan. 3) Remove any aggregate particles stuck in the sieve openings. Measure and record the mass of each empty sieve. 4) Place the sieves in the shaker with the largest sieve opening at the top and progressing to smaller sizes at each next lower sieve position. 5) For the CA-6 aggregate, lay the ¾-inch sieve on top of the machine to collect any particles larger than the sieve size. 6) Pour the aggregate onto the sieves. For the CA-6 aggregate, work all smaller sizes through the ¾-inch sieve then remove it from the machine. Gently distribute the material and shake the ¾-inch sieve so that all smaller sizes fall through to the sieve below. Remove the sieve from the top of the machine and weigh it. 7) Place the dust cover over the top and front of the shaker. 8) Tighten the cranks on top of the machine to firmly hold the sieves. Do not overtighten. 9) Turn on the shaker and let it run for at least 5 minutes. If at any time the cranks begin to rotate, stop the machine and re-tighten the crank(s) that turned. Then start the machine to finish the 5-minute shaking period. 10) After stopping the machine, allow about 1 minute before removing the cover to allow some of the dust to settle. 11) Remove each sieve, weigh it and record the combined mass of the sieve and aggregate. Weigh to the nearest gram. Page 3 of 19
12) After all the sieves and the pan with their retained particles are weighed calculate the total mass retained. If the total of the amount retained is not within 0.3 percent of the original amount placed in the sieve stack, then again measure and record the mass of all the sieves with their retained sample. Discard the retained sample, and the mass of each of the empty sieves. Recalculate the total of the amounts retained. Use the results of the retained totals that most closely match the original mass of the aggregate used. 13) Empty the sieves as instructed by the instructor or TA and remove any particles stuck in the sieve openings. Brush the dust from each sieve. 14) Finish calculations before leaving the lab. I. (C) Bulk Unit Weight of Coarse Aggregate 1. Generalized Procedure An air-dried sample of coarse aggregate has been prepared. 1) Quarter or split the sample to the desired size (about 25 kg). 2) Calculate the volume of container (hint: around 1/3 ft 3 ) 3) Use the rodding procedure for compact weight determination. 4) Calculate the bulk unit weight, voids and solid density. 2. Preparatory Reading ASTM C 29; AASHTO T 19: Bulk Density ( Unit Weight ) and Voids in Aggregate Voids in aggregate by rodding: Voids, % = [(Bulk Sp Gr OD x γ W ) Unit Wt.(E)] / [Bulk Sp Gr OD x γ W ] * 100 Solid Density (OD) = Bulk Sp Gr OD x γ W I. (D) Natural Moisture Content of Coarse Aggregate 1. Objective To acquaint the student with moisture content tests on coarse aggregate. Values obtained from tests will be used later in the course in the design of concrete mixes. 2. Preparatory Reading ASTM C566; AASHTO T255; Moisture Content by Drying in Oven. 3. Generalized Procedure A natural dry sample of coarse aggregate has been prepared. Use a sample of about 4000 g for CA-11 and 1500 g of CA-6. Page 4 of 19
1) Collect a sample of the air-dried aggregate. 2) Use a precision balance to measure the weight of the bowl to be used for drying in the oven. Measure to within 0.1%. 3) Add the sample to the bowl and record the combined mass in the table. 4) Place the sample in an oven set to 230±10ºF (105±5ºC) for about 24 hours. 5) Remove the sample from the oven and allow it to cool. Use a fan to speed cooling. It is not necessary to cool the sample to room temperature. 6) Measure the total weight of the bowl and oven-dried sample. Record the mass in the table. 7) Calculate the moisture content. I. (E) Washed Sieve Analysis of Coarse Aggregate (CA-6) 1. Objective The objective of this experiment is to acquaint the student with washed sieve tests performed on coarse aggregate. The purpose of this test is to determine the total percentage (by mass) of minus No. 200 particles in an aggregate sample since some of the finer particles are typically not separated from the coarse aggregate using the dry sieve test. The percentage (by mass) of minus No. 200 particles obtained in the dry sieve test will be subtracted from the total percentage (by mass) of minus No. 200 obtained in this test. Values obtained from this test will be used later in the course in the design of asphalt mixes. 2. Preparatory Reading ASTM C 177; AASHTO T 11: Materials Finer Than 75-μm (No. 200) Sieve in Mineral Aggregates by Washing 3. Generalized Procedure 1) An air-dried sample of coarse aggregate has been prepared. 2) Collect a sample (about 1000 g) of the air-dried aggregate. 3) Use a precision balance to measure the weight of the bowl to be used for drying in the oven. Measure to within 0.1%. 4) Add the appropriate amount of sample to the bowl and record the combined mass in the table. 5) Place the sample in an oven set to 230±10ºF (105±5ºC) for about 24 hours. 6) Remove the sample from the oven and allow it to cool. Use a fan to speed cooling. It is not necessary to cool the sample to room temperature. 7) Use a precision balance to measure the total weight of the oven-dried sample. Record the mass in the table. 8) Place the sample in a deep, No. 200 sieve. Run tap water through the sample while gently stirring the aggregate with your fingers. Continue washing the sample until the water draining from the sieve runs clear. 9) Empty all the aggregate retained on the sieve into a ceramic or metal bowl. Put the sample in the oven and allow it to dry for about 24 hours. Page 5 of 19
10) Remove the sample from the oven and allow it to cool. Use a fan to speed cooling. 11) Use a precision balance to measure the total weight of the oven-dried, washed sample to within 0.1%. Record the mass in the table. II. FINE AGGREGATE II. (A) Specific Gravity and Absorption of Fine Aggregate 1. Objective To acquaint the student with specific gravity and absorption tests on fine aggregate. Values obtained from these tests will be used later in the course in the design of concrete mixes. 2. Preparatory Reading ASTM C 128; AASHTO T84; Specific Gravity and Absorption of Fine Aggregates 3. General Procedure A sample of fine aggregate (about 1000 g) has been soaking in water for 24 hours and is considered to be fully saturated. (a) Absorption 1) Pour off as much water as possible and then dry the sample to a SSD condition using a fan or blower. 2) Add some of the sample into the brass cone and use the rod to make it firm by tamping. Fill and tamp in three layers using 15 blows per layer. 3) Lift the cone and if the sand slumps freely then it is considered to be in the SSD condition. 4) Weigh the SSD sample in air. 5) Put the SSD sample in the oven to dry. Once the SSD sample is dry determine the moisture content. (b) Specific Gravity 1) Put distilled water into pycnometer to 2/3 of the way to the calibrated 500-ml mark. Use a vacuum to remove the entrapped air. 2) Add distilled water to the pycnometer up to the mark and vacuum again until the air again is removed. 3) Using the squeeze plastic bottle add more water to bring the level up to the mark. 4) Weigh the pycnometer filled with distilled water. 5) Drain out about 2/3 of the distilled water into a beaker and save it for later use. 6) Deposit the fine aggregate sample into the partially filled pycnometer. Again use vacuum to remove any trapped air. Then add water to bring the level up to the Page 6 of 19
mark. If any air bubbles remain then use the vacuum to remove the air and adjust the water level if needed. 7) Weigh the aggregate sample with water and pycnometer. 8) Weigh an empty dish. 9) Wash of the aggregate from the pycnometer into the dish. 10) Put the dish with wet aggregate into the oven for about 24 hours. 11) Remove the sample from the oven and allow it to cool. It is not necessary to cool the sample to room temperature. 12) Get the oven-dry weight. 13) Calculate the specific gravity of the aggregate sample. II. (B) Sieve Analysis of Fine Aggregate 1. Object To acquaint the student with sieve analyses tests on fine aggregate. Values obtained from tests will be used later in the course in the design of concrete mixes. 2. Preparatory Reading ASTM C 136; AASHTO T27; Sieve Analysis of Coarse and Fine Aggregates ASTM C 33; AASHTO M6; Fine Aggregate for PCC Specification. 3. General Procedure A sample of fine aggregate has been dried overnight in an oven for the purpose of obtaining a moisture-free sample. 1) Use # 4, #8, #16, #30, #50 and #100 sieves (8-inch diameter) and pan. Record the mass of each sieve and the pan. 2) Stack the sieves with the large sieve size opening at the top and progressing to the smaller sizes with the pan at the bottom. 3) Get total weight of sample (approximately 500 g).deposit the sample into the top sieve and put the cover on. 4) Place the sieve stack into the shaker and shake the sieves for 5 minutes. 5) Weigh the sample retained on each sieve and pan to the nearest 0.1 gram. Do NOT discard the sample yet. 6) After all the sieves and the pan with their retained particles are weighed calculate the total mass retained. If the total of the amount retained is not within 0.3 percent of the original amount placed in the sieve stack, then again measure and record the mass of all the sieves with their retained sample. Discard the retained sample, and the mass of each of the empty sieves. Recalculate the total of the amounts retained. Use the results of the retained totals that most closely match the original mass of the aggregate used. 7) Empty the sieves as instructed by the instructor or TA and remove any particles stuck in the sieve openings. Brush the dust from each sieve. Page 7 of 19
II. (C) Natural Moisture Content of Fine Aggregate 1. Object To acquaint the student with moisture content tests on fine aggregate. Values obtained from tests will be used later in the course in the design of concrete mixes. 2. Preparatory Reading ASTM C566; AASHTO T255; Moisture Content by Drying in Oven. 3. Generalized Procedure A natural dry sample of fine sand aggregate has been prepared. II. (E) Washed Sieve Analysis of Fine Aggregate (FA-20) 1. Objective The objective of this experiment is to acquaint the student with washed sieve tests on fine aggregate. The purpose of this test is to determine the total percentage (by mass) of minus No. 200 particles since some of the finer particles are typically not separated from the coarse aggregate using the dry sieve test. The percentage (by mass) of minus No. 200 particles obtained in the dry sieve test will be subtracted from the total percentage (by mass) of minus No. 200 obtained in this test. Values obtained from this test will be used later in the course in the design of asphalt mixes. 2. Preparatory Reading ASTM C 177; AASHTO T 11: Materials Finer Than 75-μm (No. 200) Sieve in Mineral Aggregates by Washing 3. Generalized Procedure 1) An air-dried sample of FA-20 fine aggregate has been prepared. 2) Collect a sample of approximately 1000 g of the air-dried aggregate. 3) Place the sample in an oven set to for about 24 hours. 4) Remove the sample from the oven and allow to cool. Use a fan to speed cooling. 5) Use a precision balance to measure the total weight of the oven-dried sample to within 0.1%. Record the mass in Table 15. 6) Placed the sample in a deep, No. 200 sieve. Run tap water through the sample while gently stirring the aggregate with your fingers. Continue washing the sample until the water draining from the sieve runs clear. 7) Empty all the aggregate retained on the sieve into a ceramic or metal bowl. Put the sample in the oven and allow to dry for 24 hours. 8) Remove the sample from the oven and allow to cool. Use a fan to speed cooling. Page 8 of 19
9) Use a precision balance to measure the total weight of the oven- dried, washed sample to within 0.1%. Record the mass in the table below. End of Procedures Tables Follow Page 9 of 19
Table 1. Data Sheet Specific Gravity and Absorption (CA-11) Weight of oven dry sample in air (A) Weight of SSD sample in air (B) Weight of Saturated-Surface-Dry sample in water (C) Bulk specific gravity (OD) = A / (B-C) Bulk specific gravity (SSD) = B / (B-C) Apparent specific gravity = A / (A-C) Absorption = (B-A) / A * 100% (%) Table 2. Data Sheet Specific Gravity and Absorption (CA-6) Weight of oven dry sample in air (A) Weight of SSD sample in air (B) Weight of Saturated-Surface-Dry sample in water (C) Bulk specific gravity (OD) = A / (B-C) Bulk specific gravity (SSD) = B / (B-C) Apparent specific gravity = A / (A-C) Absorption = (B-A) / A * 100% (%) Page 10 of 19
Table 3. Data Sheet Dry Sieve Analysis (CA-11) Sieve Size Grams Cumulative ASTM C33 Specs. Comment (P or F) IDOT CA-11 Specs. Comment (P or F) 1 inch ¾ inch ½ inch #4 #8 Pan Total Table 4. Data Sheet Dry Sieve Analysis (CA-6) Sieve Size Grams Cumulative ASTM C33 Specs. Comment (P or F) IDOT CA-11 Specs. Comment (P or F) ¾ inch ⅜ inch #4 #8 #16 #30 #200 Pan Total Page 11 of 19
Table 5. Data Sheet Bulk Unit Weight (CA-11) (A) Weight of Rodded Aggregate + Bucket (lbs) (B) Tare weight of empty bucket (lbs) (C) Net weight of aggregate sample (A-B) (1bs) (D) Volume of bucket (ft 3 ) (E) Unit weight of aggregate = C / D (by rodding) (lbs/ft 3 ) Table 6. Data Sheet Moisture Content (CA-11) Pan number Pan weight (A) Natural (wet) sample & pan weight (B) Dry sample & pan weight (C) Water weight (B C) Dry sample weight (C-A) Moisture content (B-C) / (C-A) * 100% (%) Page 12 of 19
Table 7. Data Sheet Moisture Content (CA-6) Pan number Pan weight (A) Natural (wet) sample & pan weight (B) Dry sample & pan weight (C) Water weight (B C) Dry sample weight (C-A) Moisture content (B-C) / (C-A) * 100% (%) Table 8. Data Sheet Washed Sieve Analysis of Coarse Aggregate (CA-6) Pan number Pan weight, A Initial oven-dried sample & pan weight, B Initial oven dried sample weight, C=B-A Final oven-dried washed sample & pan weight, D Final oven dried washed sample weight, E=D-A Total age of Minus #200 content, F=[(C-E) / C ]* 100% (%) Page 13 of 19
Table 9A. Data Sheet - Absorption of Fine Aggregate (FA-01) Empty moisture can weight A (SSD sample + can) weight B (Dry Sample + can) weight C Weight of water D = B - C Dry sample weight E = C - A Absorption (%) F = D / E*100% (%) Table 9B. Data Sheet Specific Gravity of Fine Aggregate (FA-01) Weight of (empty pycnometer + water) A Weight of (empty pycnometer + SSD sample + water) B Weight of empty drying container C Weight of (SSD sample same volume of water) D = B - A Weight of (oven-dry sample + empty container) E Weight of oven-dry (OD) sample F = E C Weight of same volume of water G = F - D Bulk specific gravity (OD) Bulk specific gravity (SSD) 1 Absorption is expressed as a decimal number here. H = F / G I = H * (1+ absorption 1 ) Page 14 of 19
Table 10A. Data Sheet - Absorption of Fine Aggregate (FA-20) Empty moisture can weight A (SSD sample + can) weight B (Dry Sample + can) weight C Weight of water D = B - C Dry sample weight E = C - A Absorption (%) F = D / E*100% (%) Table 10B. Data Sheet Specific Gravity of Fine Aggregate (FA-20) Weight of (empty pycnometer + water) A Weight of (empty pycnometer + SSD sample + water) B Weight of empty drying container C Weight of (SSD sample same volume of water) D = B - A Weight of (oven-dry sample + empty container) E Weight of oven-dry (OD) sample F = E C Weight of same volume of water G = F - D Bulk specific gravity (OD) Bulk specific gravity (SSD) H = F / G I = H * (1+ absorption 1 ) 1 Absorption is expressed as a decimal number here. Page 15 of 19
Table 11. Data Sheet Dry Sieve Analysis of Fine Aggregate (FA-01) Sieve Size Grams Cumulative ASTM C33 Specs. Comment (P or F) IDOT FA-01 Specs. Comment (P or F) #4 #8 #16 #30 #50 #100 Pan Total Table 11a. Fineness Modulus Sieve Size 3 1½ 3/4 3/8 #4 #8 #16 #30 #50 Cumulative % #10 0 Cumulative % Total F.M. = Cumulative % Total / 100 = (FA-01) Page 16 of 19
Table 12. Data Sheet Dry Sieve Analysis of Fine Aggregate (FA-20) Sieve Size Grams Cumulative ASTM C33 Specs. Comment (P or F) IDOT FA-20 Specs. Comment (P or F) #4 #8 #16 #30 #50 #100 Pan Total Table 12a. Fineness Modulus Sieve Size 3 1½ 3/4 3/8 #4 #8 #16 #30 #50 #100 Cumulative % Total Cumulative % F.M. = Cumulative % Total / 100 = (FA-20) Page 17 of 19
Table 13. Data Sheet - Natural Moisture Content of Fine Aggregate (FA-01) Pan number Pan weight (A) Natural (wet) sample & pan weight (B) Dry sample & pan weight (C) Water weight (B C) Dry sample weight (C-A) Moisture content (B-C) / (C-A)* 100% (%) Table 14. Data Sheet - Natural Moisture Content of Fine Aggregate (FA-20) Pan number Pan weight (A) Natural (wet) sample & pan weight (B) Dry sample & pan weight (C) Water weight (B C) Dry sample weight (C-A) Moisture content (B-C) / (C-A) * 100% (%) Page 18 of 19
Table 15. Data Sheet Washed Sieve Analysis of Fine Aggregate (FA-20) Pan number Pan weight, A Initial oven-dried sample & pan weight, B Initial oven dried sample weight, C=B-A Final oven-dried washed sample & pan weight, D Final oven dried washed sample weight, E=D-A Total age of Minus No. 200 content, F=[(C-E) / C ]* 100% (%) Page 19 of 19