1、Standard Method of Test for Uncompacted Void Content of Fine Aggregate AASHTO Designation: T 304-17 Technical Section: 1c, Aggregates Release: Group 3 (August 2017) American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-1
2、c T 304-1 AASHTO Standard Method of Test for Uncompacted Void Content of Fine Aggregate AASHTO Designation: T 304-17 Technical Section: 1c, Aggregates Release: Group 3 (August 2017) 1. SCOPE 1.1. This method describes the determination of the loose uncompacted void content of a sample of fine aggreg
3、ate. When measured on any aggregate of a known grading, void content provides an indication of that aggregates angularity, sphericity, and surface texture compared with other fine aggregates tested in the same grading. When void content is measured on an as-received fine aggregate grading, it can be
4、 an indicator of the effect of the fine aggregate on the workability of a mixture in which it may be used. 1.2. Three procedures are included for the measurement of void content. Two use graded fine aggregate (standard grading or as-received grading), and the other uses several individual size fract
5、ions for void content determinations: 1.2.1. Standard Graded Sample (Method A)This method uses a standard fine aggregate grading that is obtained by combining individual sieve fractions from a typical fine aggregate sieve analysis. See Section 9, Preparation of Test Samples, for the grading. 1.2.2.
6、Individual Size Fractions (Method B)This method uses each of three fine aggregate size fractions: (a) 2.36 mm (No. 8) to 1.18 mm (No. 16); (b) 1.18 mm (No. 16) to 600 m (No. 30); and (c) 600 m (No. 30) to 300 m (No. 50). For this method, each size is tested separately. 1.2.3. As-Received Grading (Me
7、thod C)This method uses that portion of the fine aggregate finer than a 4.75-mm (No. 4) sieve. 1.2.4. See Section 5, Significance and Use, for guidance on the method to be used. 1.3. The values stated in SI units shall be regarded as the standard. 1.4. This standard does not purport to address all o
8、f the safety concerns associated with its use. It is the responsibility of the user of this procedure to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to its use. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: R 76, Reducing Samp
9、les of Aggregate to Testing Size T 2, Sampling of Aggregates T 11, Materials Finer Than 75-m (No. 200) Sieve in Mineral Aggregates by Washing T 19M/T 19, Bulk Density (“Unit Weight”) and Voids in Aggregate 2017 by the American Association of State Highway and Transportation Officials. All rights res
10、erved. Duplication is a violation of applicable law.TS-1c T 304-2 AASHTO T 27, Sieve Analysis of Fine and Coarse Aggregates T 84, Specific Gravity and Absorption of Fine Aggregate 2.2. ASTM Standards: C125, Standard Terminology Relating to Concrete and Concrete Aggregates C778, Standard Specificatio
11、n for Standard Sand 2.3. ACI Document: ACI 116R, Cement and Concrete Terminology13. TERMINOLOGY 3.1. Terms used in this standard are defined in ASTM C125 or ACI 116R. 4. SUMMARY OF TEST METHOD 4.1. A nominal 100-mL calibrated cylindrical measure is filled with fine aggregate of prescribed grading by
12、 allowing the sample to flow through a funnel from a fixed height into the measure. The fine aggregate is struck off, and its mass is determined by weighing. Uncompacted void content is calculated as the difference between the volume of the cylindrical measure and the absolute volume of the fine agg
13、regate collected in the measure. Uncompacted void content is calculated using the bulk dry specific gravity of the fine aggregate. Two runs are made on each sample and the results are averaged. 4.1.1. For a graded sample (Method A or Method C), the percent void content is determined directly, and th
14、e average value from two runs is reported. 4.1.2. For the individual size fractions (Method B), the mean percent void content is calculated using the results from tests of each of the three individual size fractions. 5. SIGNIFICANCE AND USE 5.1. Methods A and B provide percent void content determine
15、d under standardized conditions that depend on the particle shape and texture of a fine aggregate. An increase in void content by these procedures indicates greater angularity, less sphericity, or rougher surface texture, or some combination of the three factors. A decrease in void content results i
16、s associated with more rounded, spherical, smooth-surfaced fine aggregate, or a combination of these factors. 5.2. Method C measures the uncompacted void content of the minus 4.75-mm (No. 4) portion of the as-received material. This void content depends on grading as well as particle shape and textu
17、re. 5.3. The void content determined on the standard graded sample (Method A) is not directly comparable with the average void content of the three individual size fractions from the same sample tested separately (Method B). A sample consisting of single-size particles will have a higher void conten
18、t than a graded sample. Therefore, use either one method or the other as a comparative measure of shape and texture, and identify which method has been used to obtain the reported data. Method C does not provide an indication of shape and texture directly if the grading from sample to sample changes
19、. 5.3.1. The standard graded sample (Method A) is most useful as a quick test that indicates the particle shape properties of a graded fine aggregate. Typically, the material used to make up the standard 2017 by the American Association of State Highway and Transportation Officials. All rights reser
20、ved. Duplication is a violation of applicable law.TS-1c T 304-3 AASHTO graded sample can be obtained from the remaining size fractions after performing a single sieve analysis of the fine aggregate. 5.3.2. Obtaining and testing individual size fractions (Method B) is more time consuming and requires
21、 a larger initial sample than using the graded sample. However, Method B provides additional information concerning the shape and texture characteristics of individual sizes. 5.3.3. Testing samples in the as-received grading (Method C) may be useful in selecting proportions of components used in a v
22、ariety of mixtures. In general, high void content suggests that the material could be improved by providing additional fines in the fine aggregate or more cementitious material may be needed to fill voids between particles. 5.3.4. The bulk dry specific gravity of the fine aggregate is used in calcul
23、ating the void content. The effectiveness of these methods of determining void content and its relationship to particle shape and texture depends on the bulk specific gravity of the various size fractions being equal, or nearly so. The void content is actually a function of the volume of each size f
24、raction. If the type of rock or mineral or its porosity varies markedly in any of the size fractions, it may be necessary to determine the specific gravity of the size fractions used in the test. 5.4. Void content information from Methods A, B, or C will be useful as an indicator of properties such
25、as: the mixing water demand of hydraulic cement concrete; flowability, pumpability, or workability factors when formulating grouts or mortars; or, in bituminous concrete, the effect of the fine aggregate on stability and voids in the mineral aggregate; or the stability of the fine aggregate portion
26、of a base course aggregate. 6. APPARATUS 6.1. Cylindrical MeasureA right cylinder of approximately 100 mL capacity having an inside diameter of approximately 39 mm and an inside height of approximately 86 mm. The cylinder shall be a piece of metal with a seamless smooth wall. The bottom of the measu
27、re shall be metal at least 6 mm thick, shall be firmly sealed to the cylinder, and shall be provided with means for aligning the axis of the cylinder with that of the funnel (see Figure 1). 6.2. FunnelThe lateral surface of the right frustum of a cone sloped 60 4 from the horizontal with an opening
28、of 12.7 0.6 mm diameter. The funnel section shall be a piece of metal, smooth on the inside and at least 38 mm high. It shall have a volume of at least 200 mL or shall be provided with a supplemental glass or metal container to provide the required volume (see Figure 2). Note 1Pycnometer top C9455 (
29、sold by Hogentogler and Co., Inc., 9515 Gerwig, Columbia, MD 21046, 410-381-2390) is satisfactory for the funnel section, except that the size of the opening has to be enlarged and any burrs or lips that are apparent should be removed by light filing or sanding before use. This pycnometer top must b
30、e used with a suitable glass jar with the bottom removed (see Figure 2). 6.3. Funnel StandA three- or four-legged support capable of holding the funnel firmly in position with the axis of the funnel colinear (within a 4-degree angle and a displacement of 2 mm) with the axis of the cylindrical measur
31、e. The funnel opening shall be 115 2 mm above the top of the cylinder. A suitable arrangement is shown in Figure 2. 2017 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-1c T 304-4 AASHTO Figure 1Nominal 1
32、00-mL Cylindrical Measure Figure 2Suitable Funnel Stand Appa ratus with Cylindrical Measure in Place 41 mm approx39 mm approxMetal CylinderEpoxy Resin-FilledJointMetal PlateMinimum 6 mm thick3.5 0.4 mmApprox 6-mm Dia Drilled HoleApprox 3 mm deepUsed for Centering Containeron a Mating Dowel in the Ce
33、nterof the Stand Base86 mm approxSection through Center of Apparatus115 2mmMin 38 mm60 4Dia of12.7 0.6 mmPan to RetainFine AggregateParticlesNominal100-mLMeasure1-qt (L)Mason JarPyncnometer(Remove bottomof glass jar.)CL 2017 by the American Association of State Highway and Transportation Officials.
34、All rights reserved. Duplication is a violation of applicable law.TS-1c T 304-5 AASHTO 6.4. Glass PlateA square glass plate approximately 60 mm by 60 mm with a minimum 4-mm thickness used to calibrate the cylindrical measure. 6.5. PanA flat metal or plastic pan of sufficient size to contain the funn
35、el stand and to prevent loss of material. The purpose of the pan is to catch and retain fine aggregate particles that overflow the measure during filling and strike off. The pan shall not be warped so as to prevent rocking of the apparatus during testing. 6.6. Metal SpatulaWith a blade approximately
36、 100 mm long, and at least 20 mm wide, with straight edges. The end shall be cut at a right angle to the edges. The straight edge of the spatula blade is used to strike off the fine aggregate. 6.7. Scale or BalanceAccurate and readable to 0.1 g within the range of use, capable of weighing the cylind
37、rical measure and its contents. 7. SAMPLING 7.1. The sample(s) used for this test shall be obtained using T 2 and R 76, or from sieve analysis samples used for T 27, or from aggregate extracted from a bituminous concrete specimen. For Methods A and B, the sample is washed over a 150-m (No. 100) or 7
38、5-m (No. 200) sieve in accordance with T 11 and then dried and sieved into separate size fractions according to T 27 procedures. Maintain the necessary size fractions obtained from one (or more) sieve analysis in a dry condition in separate containers for each size. For Method C, dry a split of the
39、as-received sample in accordance with the drying procedure in T 27. 8. CALIBRATION OF CYLINDRICAL MEASURE 8.1. Apply a light coat of grease to the top edge of the dry, empty cylindrical measure. Weigh the measure, grease, and glass plate. Fill the measure with freshly boiled, deionized water at a te
40、mperature of 18 to 24C. Record the temperature of the water. Place the glass plate on the measure, being sure that no air bubbles remain. Dry the outer surfaces of the measure and determine the combined mass of measure, glass plate, grease, and water by weighing. Following the final weighing, remove
41、 the grease, and determine the mass of the clean, dry, empty measure for subsequent tests. 8.2. Calculate the volume of the measure as follows: 1000MVD= (1) where: V = volume of cylinder, mL; M = net mass of water, g; and D = density of water (see Table 3 in T 19M/T 19 for density at the temperature
42、 used), kg/m3. Determine the volume to the nearest 0.1 mL. Note 2If the volume of the measure is greater than 100.0 mL, it may be desirable to grind the upper edge of the cylinder until the volume is exactly 100.0 mL, to simplify subsequent calculations. 2017 by the American Association of State Hig
43、hway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-1c T 304-6 AASHTO 9. PREPARATION OF TEST SAMPLES 9.1. Method AStandard Graded SampleWeigh out and combine the following quantities of fine aggregate, which has been dried and sieved in accordance
44、with T 27. Individual Size Fraction Mass, g 2.36 mm (No. 8) to 1.18 mm (No. 16) 44 1.18 mm (No. 16) to 600 m (No. 30) 57 600 m (No. 30) to 300 m (No. 50) 72 300 m (No. 50) to 150 m (No. 100) 17 190 The tolerance on each of these amounts is 0.2 g. 9.2. Method BIndividual Size FractionsPrepare a separ
45、ate 190-g sample of fine aggregate, dried and sieved in accordance with T 27, for each of the following size fractions: Individual Size Fraction Mass, g 2.36 mm (No. 8) to 1.18 mm (No. 16) 190 1.18 mm (No. 16) to 600 m (No. 30) 190 600 m (No. 30) to 300 m (No. 50) 190 The tolerance on each of these
46、amounts is 1 g. Do not mix these samples together. Each size is tested separately. 9.3. Method CAs-Received GradingPass the sample (dried in accordance with T 27) through a 4.75-mm (No. 4) sieve. Obtain a 190 1-g sample of the material passing the 4.75-mm (No. 4) sieve for test. 9.4. Specific Gravit
47、y of Fine AggregateIf the bulk dry specific gravity of fine aggregate from the source is unknown, determine it on the minus 4.75-mm (No. 4) material according to T 84. Use this value in subsequent calculations unless some size fractions differ by more than 0.05 from the specific gravity typical of t
48、he complete sample, in which case the specific gravity of the fraction (or fractions) being tested must be determined. An indicator of differences in specific gravity of various particle sizes is a comparison of specific gravities run on the fine aggregate in different gradings. Specific gravity can
49、 be run on gradings with and without specific size fractions of interest. If specific gravity differences exceed 0.05, determine the specific gravity of the individual 2.36-mm (No. 8) to 150-m (No. 100) sizes for use with Method A or the individual size fractions for use with Method B either by direct measurement or by calculation using the specific gravity data on gradings with and without the size fraction of interest. A difference in specific gravity of 0.05 will change the calculated void content about 1
