1、Standard Method of Test for Specific Gravity and Absorption of Aggregate by Volumetric Immersion Method AASHTO Designation: T 354-151American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-1c T 354-1 AASHTO Standard Method
2、 of Test for Specific Gravity and Absorption of Aggregate by Volumetric Immersion Method AASHTO Designation: T 354-1511. SCOPE 1.1. This method covers the determination of bulk and apparent specific gravity and absorption of fine and coarse aggregate at 20 1C (70 2F) for dry and saturated aggregates
3、. 1.2. This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns associated with its use. It is the responsibility of whoever uses this standard to consult and establish appropriate safety and health practices and d
4、etermine the applicability of regulatory limitations prior to use. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: M 231, Weighing Devices Used in the Testing of Materials T 2, Sampling of Aggregates T 19M/T 19, Bulk Density (“Unit Weight”) and Voids in Aggregate T 84, Specific Gravity and Absorption
5、 of Fine Aggregate T 85, Specific Gravity and Absorption of Coarse Aggregate T 248, Reducing Samples of Aggregate to Testing Size T 255, Total Evaporable Moisture Content of Aggregate by Drying 3. SIGNIFICANCE AND USE 3.1. Bulk specific gravity is the characteristic generally used for calculations o
6、f the volume occupied by the aggregate in various mixtures containing aggregate including portland cement concrete (PCC), bituminous concrete, and other mixtures that are proportioned or analyzed on an absolute volume basis. Bulk specific gravity is also used in the computation of voids in aggregate
7、 in T 19M/T 19. Bulk specific gravity determined on the saturated surface-dry basis is used if the aggregate is wet, that is, if its absorption has been satisfied. Conversely, the bulk specific gravity determined on the oven-dry basis is used for computations when the aggregate is dry or assumed to
8、be dry. 3.2. Apparent specific gravity pertains to the relative density of the solid material making up the constituent particles not including the pore space within the particles that is accessible to water. This value is not widely used in construction aggregate technology. 3.3. When it is deemed
9、that the aggregate has been in contact with water long enough to satisfy most of the absorption potential, the absorption values are used to represent the change in the mass of an aggregate due to water absorbed into the pore spaces within the constituent particles, compared to the dry condition. Th
10、e laboratory standard for absorption is that obtained after submerging dry 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1c T 354-2 AASHTO aggregate for approximately 15 h in water. Aggregates mined
11、 from below the water table may have a higher absorption when used, if not allowed to dry. Conversely, some aggregates when used may contain an amount of absorbed moisture less than the 15-h soaked condition. For an aggregate that has been in contact with water and that has free moisture on the part
12、icle surfaces, the percentage of free moisture can be determined by deducting the absorption from the total moisture content determined by T 255 drying. 3.4. Users of this method are encouraged to be cautious in applying the results. Values achieved for specific gravity and absorption are significan
13、tly different from those achieved from T 84 and T 85. Results from this method will affect the calculated results for volumetrics in hot mix asphalt (HMA) and absorption in PCC. The user is cautioned to thoroughly evaluate these effects before implementing this test method. A graphical method and so
14、urce/aggregate specific correlation method are shown in the Appendix that can be used to correlate results to T84 and T85. The methods discussed in Appendix X2.1 or X2.2 should be utilized when the values from this method are to be directly substituted for those from T 84 or T 85. 4. APPARATUS 4.1.
15、Flask with Plug for Coarse AggregateA glass flask with a bulb volume of 3000 to 4000 mL and a separate plug. The neck of the flask shall be marked with 5 mL graduated increments that correspond to a precision of at least 0.1 percent of the sample volume. Overall length of the flask is approximately
16、760 mm (30 in.). (See Note 1 and Figure 1.) 4.2. Flask for Fine AggregateA glass flask with a bulb volume of 2000 mL. The neck of the flask shall be marked with 1 mL graduated increments that correspond to a precision of at least 0.1 percent of the sample volume. Overall length of the flask is appro
17、ximately 760 mm (30 in.). (See Note 1 and Figure 1.) Note 1The flask to be used for fine aggregate will have a neck approximately 25 mm (1 in.) in diameter. The flask used for coarse aggregate will have a neck approximately 51 mm (2 in.) in diameter. These flasks are available from Humboldt Manufact
18、uring Company, 7300 W. Agatite Avenue, Norridge, IL 60706. Figure 1Typical Flask 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1c T 354-3 AASHTO 4.3. Scale with a capacity of at least 10 000 gThe sc
19、ale shall comply with the requirements in M 231. 4.4. Minimum 450-mm (18-in.) long rod with dry, absorbent swab. 4.5. Timer that can be read to the nearest second, and that can measure elapsed time up to 24 h. 5. CALIBRATION OF FLASK 5.1. Determine and record the empty weight of the flask, to the ne
20、arest gram. 5.2. Fill flask with distilled water at 20 1C (70.0 2F) such that the bottom of the meniscus is exactly even with the zero mark. Note 2If a flask does not have a zero mark, add water to the first major graduation (10 mL mark on a fine aggregate flask); then subtract that amount from the
21、calibrated flask volume in Equation 1. 5.3. Determine and record the weight of the filled flask to the nearest gram. 5.4. Determine the calibrated volume of the flask as follows: Vcal= B A (1) where: Vcal= calibrated volume of the flask, mL; A = weight of empty flask, g; and B = weight of flask fill
22、ed with water, g. Note 3Due to the definition of a milliliter and a gram (1 milliliter of water weighs 1 gram), these values can be interchanged without conversions. 6. SAMPLING 6.1. Sampling of aggregate shall be accomplished in accordance with T 2. 7. PREPARATION OF TEST SPECIMEN 7.1. Obtain appro
23、ximately 2 kg of fine aggregate or 3 kg of coarse aggregate using the applicable procedures described in T 248. 7.2. Dry the sample in an oven or a suitable pan or vessel to constant mass at a temperature of 110 5C (230 9F). Allow it to cool to comfortable handling temperature, without allowing it t
24、o re-absorb any water from the surrounding environment. This can be accomplished by covering the container with a plate or cover that blocks direct access of the ambient humid air to the cooling sample. 8. TEST PROCEDURE 8.1. Weigh out 1200 10 g of oven-dry fine aggregate or 2500 50 g of oven-dry co
25、arse aggregate to be tested. If testing lightweight aggregate, reduce the amount of material to 600 10 g for fine aggregate, or 900 g 10 g for coarse aggregate. 8.2. The actual weight, Wd, of oven dry aggregate should be recorded to the nearest 0.01 grams. 2015 by the American Association of State H
26、ighway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1c T 354-4 AASHTO 8.3. Fill the bottom portion of the flask approximately one half full, by height, with 20 1C (70 2F) distilled water. (See Note 4.) 8.4. Measure out, but do not add, approximate
27、ly 250 g of 20 1C (70 2F) distilled water. Note 4The volume of water in Sections 8.3 and 8.4 may need to be adjusted for the individual flask being used. It is important that during the filling process, the combined initial volume of water and the dry aggregate not plug the neck of the flask. Theref
28、ore, the following procedure is intended to allow sufficient water for the aggregate to become completely submerged, but to not rise into the narrow neck of the flask. 8.5. Dry the inside of the neck of the flask with a dry absorbent swab. Note 5If the inside of the neck is not completely dry, finer
29、 portions of the sample may adhere to the moisture, plugging the neck of the flask as the sample is added. 8.6. Pour the aggregate sample into the flask as quickly as possible, without plugging the neck. Note 6It is recommended that an outside funnel not be used. The sand has a tendency to plug the
30、smaller hole of the funnel, whereas it typically pours through the built-in funnel without plugging. 8.7. Start the timer immediately when the aggregate first hits the water in the flask. 8.8. After all of the sample has been poured into the flask, immediately add enough of the holdback water measur
31、ed out in Section 8.4 to raise the water level sufficiently up into the graduated portion of the neck of the flask, so that the water level does not drop below the graduated portion during the duration of the test. 8.9. Do not shake, agitate, or otherwise disturb the flask at this time. 8.10. Take t
32、he reading of the initial water level, Ri, in the neck of the flask 30 s after the first particle has entered the water. 8.11. Determine and record the weight of the flask filled with aggregate and water, WT, to 0.1 grams. 8.12. Aggressively shake, roll, and otherwise agitate the flask in order to r
33、emove all of the released air. Place a plug into the neck of the coarse aggregate flask to prevent loss of water during the shaking and agitation of the flask. Stop shaking and agitating the flask when the timer shows 3 min. 8.13. Allow the flask to remain undisturbed for 2 min. 8.14. Obtain and rec
34、ord the reading of the water level in the neck of the flask at 5 min elapsed time (from when the aggregate first hits the water). 8.15. It is recommended that water level readings be taken at 10 min, 30 min, 60 min, 2 h, and 4 h elapsed time (see Note 7). Make sure to agitate all of the air out of t
35、he sample, and allow the flask to settle for at least 2 min before taking each reading. See Appendix X1. Note 7It is not critical that the readings are taken at the exact times shown. Record the time the water level reading is actually made. 8.16. Take the final water level reading, Rfinal, at 25 1
36、h. It is extremely important that all air released during the soak period be completely eliminated from the flask before taking the final reading. Make sure that the flask has been thoroughly and completely shaken and agitated, and then left undisturbed to allow all of the air to escape from the fla
37、sk until there is no air left in the system. Make sure that the air removal process is started early enough to completely eliminate all of the air within the designated time. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violatio
38、n of applicable law.TS-1c T 354-5 AASHTO 9. ABSORPTION 9.1. Calculate the absorption as follows: absorption, (%) 100absdWW= (2) where: Wabs= water absorbed into the sample, (Ri Rfinal), mL, where Ri= initial water level reading, mL; and Rfinal= final water level reading, mL; and Wd= original dry wei
39、ght of sample, g. 10. SATURATED BULK SPECIFIC GRAVITY (Ss) 10.1. Calculate the saturated bulk specific gravity as follows: ( )( )d abssiwWWSVV+=(3) where: Wd= original dry weight of sample, g; Wabs= water absorbed into the sample, mL; Vi= initial volume, (Ri+ Vcal), mL, where Vcal= calibrated flask
40、volume, mL; Vw= volume of test water WT (Wd+ Wf), mL, where WT= total weight of flask, water and sample, g; and Wf= weight of flask, g. 11. DRY BULK SPECIFIC GRAVITY (Sd) 11.1. Calculate the dry bulk specific gravity as follows: ( )ddiwWSVV=(4) 12. APPARENT DRY SPECIFIC GRAVITY (Sa) 12.1. Calculate
41、the apparent dry specific gravity as follows: ( ) ( )finaldad f calWSW W V WT R=+ (5) 13. CONVENTIONAL ABSORPTION 13.1. Use the correlation equation shown in Appendix X2.3 to calculate the conventional absorption for fine aggregate (T 84) as follows: ( )absorption from Section 9 1.8243conventional a
42、bsorption, (%)0.0038=+(6) 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1c T 354-6 AASHTO 13.2. Use the correlation procedure in Appendix X2.2 to determine the conventional absorption and specific g
43、ravities for fine or coarse aggregates, according to T 84 or T 85, respectively. Note 8The use of either of these methods is at the discretion of the user. The user is encouraged to use the method of preference. 14. REPORT 14.1. Report the specific gravity results to the nearest 0.001, and indicate
44、the type of specific gravity, whether bulk (dry), bulk (saturated surface-dry), or apparent. 14.2. Report the direct absorption result obtained from the direct readings to the nearest 0.1 percent. If the results are to be adjusted as described in the Appendixes, designate the procedure used, the adj
45、usted values, and the adjusted characteristics. APPENDIXES (Nonmandatory Information) X1. INTERMEDIATE WATER LEVEL READINGS X1.1. This test provides an internal quality process check. By plotting the intermediate readings against time on a logarithmic scale, an approximately straight line should be
46、determined. If the line is not essentially straight, then something happened during the performance of the test. X1.2. It also provides the ability to determine the time-rate of absorption relationship for a particular material. Once the time-rate of absorption plot has been established, it can then
47、 be used in the field. If intermediate levels of absorption are to be acknowledged during the delivery and construction procedures using this aggregate, the starting and anticipated ending points and their relative degree of saturation can be taken directly from the resulting plot. X1.3. A typical p
48、lot is shown in Figure X1.1: Figure X1.1Phunque Absorption Test 2380.02382.02384.02386.02388.02390.02392.02394.00.1 1 10 100 1000 10000Time (Minutes)Volume(ml) 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable
49、 law.TS-1c T 354-7 AASHTO X1.4. Plot the readings on semilog paper with the x-axis being time on the logarithmic scale. X1.5. Example Data: X1.6. A typical datasheet that has been found to work well with this procedure is shown in Figure X1.2. Source of Sample ABC Coarse Aggregate Type of Sample Coarse Aggregate Tare Weight of Flask, g 2094.80 2094.80 Calibrated Volume of Flask, mL 4335.90 4335.90 Dry Weight of Sample 2509.60 2513.70 Total Initial Volume of Water Added 3550.3 3664.
