1、Standard Method of Test for Determination of Composite Activation Energy of Aggregates due to AlkaliSilica Reaction (Chemical Method) AASHTO Designation: T 364-171Technical Section: 3c, Hardened Concrete Release: Group 1 (April 2017) American Association of State Highway and Transportation Officials
2、 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-3c T 364-1 AASHTO Standard Method of Test for Determination of Composite Activation Energy of Aggregates due to AlkaliSilica Reaction (Chemical Method) AASHTO Designation: T 364-171Technical Section: 3c, Hardened Concrete Release: G
3、roup 1 (April 2017) 1. SCOPE 1.1. This test method covers chemical determination of the reactivity of an as-received fine and coarse aggregate in terms of measuring composite activation energy of alkalisilica reaction (ASR), where aggregate reacts with an alkaline solution having chemistry similar t
4、o the pore solution chemistry of a conventional portland cement concrete. 1.2. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determi
5、ne the applicability of regulatory limitations prior to use. A specific precautionary statement is given in the section on reagents. Note 1The values stated in SI units are to be regarded as standard. The values in inch-pound units are shown in parentheses and are for informational purposes only. 2.
6、 REFERENCED DOCUMENTS 2.1. AASHTO Standards: M 6, Standard Specification for Fine Aggregate for Hydraulic Cement Concrete M 43, Standard Specification for Sizes of Aggregate for Road and Bridge Construction M 80, Specification for Coarse Aggregate for Hydraulic Cement Concrete M 231, Standard Specif
7、ication for Weighing Devices Used in the Testing of Materials R 76, Standard Method of Test for Reducing Samples of Aggregate to Testing Size T 2, Test Method for Sampling of Aggregates T 11, Standard Method of Test for Materials Finer than 75-m (No. 200) Sieve in Mineral Aggregates by Washing T 19,
8、 Test Method for Bulk Density (“Unit Weight”) and Voids in Aggregate T 27, Standard Method of Test for Sieve Analysis of Fine and Coarse Aggregates T 303, Accelerated Detection of Potentially Deleterious Expansion of Mortar Bars Due to Alkali-Silica Reaction 2.2. ASTM Standards: A182/A182M, Standard
9、 Specification for Forged or Rolled Alloy and Stainless Steel Pipe Flanges, Forged Fittings, and Valves and Parts for High-Temperature Service 2017 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3c T 364-
10、2 AASHTO B21/B21M, Specification for Naval Brass Rod, Bar, and Shapes C125, Terminology Relating to Concrete and Concrete Aggregates C1260, Standard Test Method for Potential Alkali Reactivity of Aggregates (Mortar-Bar Method) D1193, Specification for Reagent Water 3. SIGNIFICANCE AND STANDARD USE 3
11、.1. This test is intended to offer a rapid and reliable ASR standard test method. The as-received aggregate is immersed in an alkaline solution and allowed to react at different temperatures (i.e., 60, 70, and 80C (140, 158, and 176F). The test measures solution volume change (i.e., volume contracti
12、on) in a closed system over time (96 to 100 h) as the reaction between aggregates and solution proceeds. 3.2. The test method determines the aggregate composite activation energy (CAE) of ASR. CAE is a measure of the aggregate alkalisilica reactivity of an aggregate. For example, the lower the CAE,
13、the higher the reactivity and vice versa. CAE is used to develop an ASR aggregate classification system, which can be used as an effective screening parameter to categorize aggregates based on their reactivity. 3.3. The test method reliably predicts aggregate alkali reactivity in a short period of t
14、ime (within 5 days) and can effectively be used as an alternative to the current test method(s) (e.g., T 303 or ASTM C1260). 4. APPARATUS 4.1. ScalesThe scales and weights used for weighing materials shall conform to the requirements prescribed in M 231. 4.2. Crushing EquipmentIt is recommended to c
15、ollect aggregates from stockpile with 1-in. maximum size in order to avoid crushing. However, if any coarse aggregate contains particles with maximum size 37.5 mm (1.5 in.) then crush using suitable crushing equipment (e.g., a hand hammer) material larger than the 37.5-mm (1.5-in.) sieve to pass the
16、 37.5-mm (1.5-in.) sieve. 4.3. SievesA 25.4-mm (1-in.), 12.5-mm (1/2-in.), 4.75-mm (No. 4), 2.36-mm (No. 8), 1.18-mm (No. 16), 600-m (No. 30), 300-m (No. 50), or 150-m (No. 100) sieve. 4.4. Vacuum PumpA small vacuum pump or other suitable equipment capable of applying a vacuum pressure of 76.2 cmHg
17、(30 in.Hg). 4.5. Vibrating TableThe use of a vibrating table with variable-speed operation facilitates removal of air bubbles from solution through agitating aggregate particles during vacuuming (see Section 4.4). 4.6. GlasswareAll glass apparatus and vessels should be carefully selected to meet the
18、 particular requirements for each operation. Standard volumetric flasks, burets, and pipets should be of precision grade. 4.7. Dilatometer DeviceThe dilatometer device (see Figure 1, Note 2) consists of a stainless steel container (Figure 1a), a brass lid (Figure 1a), a stainless steel hollow tower
19、(Figure 1b), a brass housing to hold a linear variable differential transducer (LVDT) with vertical alignment (Figures 1c and 1d), and a float system consisting of a stainless steel float, a threaded rod, and an LVDT rod (Figure 2). A detailed drawing of the assembled system is provided in Figure 1.
20、 The detailed 2017 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3c T 364-3 AASHTO drawings of the individual parts are provided in Figures 1a, 1b, 1c, and 1d respectively. One end of the tower (Figure 1
21、b) is screwed into the lid (Figure 1a), and the other end is screwed into the LVDT housing (Figure 1c) with O-rings in all three junctions (i.e., 1 between the container and lid, 2 between the lid and tower, and 3 between the tower and LVDT housing). The LVDT (Note 3) is placed in the center hole of
22、 the LVDT housing and pushed into an O-ring placed at the bottom of the LVDT. The six set screws located through the side of the housing are properly tightened to ensure a vertical alignment of the LVDT. 2017 by the American Association of State Highway and Transportation Officials.All rights reserv
23、ed. Duplication is a violation of applicable law.TS-3c T 364-4 AASHTO Figure 1Cross-Sectional View of the Device 3.256 cm(1.282 in.)1.397 cm(0.550 in.)1.808 cm(0.712 in.)5.906 cm(2.325 in.)2.540 cm(1.000 in.)0.635 cm(0.250 in.)15.240 cm (6.000 in.)16.510 cm (6.500 in.)16.510 cm(6.500 in.)6.350 cm(2.
24、500 in.)1.930 cm(0.760 in.)1.270 cm(0.500 in.)0.635 cm (0.250 in.)2.858 cm(1.125 in.)2.223 cm(0.875 in.)1.905 cm(0.750 in.)1.270 cm(0.500 in.)1.155 cm(0.454 in.)6.350 cm(2.500 in.)6.467 cm(2.546 in.)2.210 cm(0.870 in.)2.210 cm(0.870 in.)0.635 cm (0.250 in.)9.525 cm(3.750 in.)1.270 cm(0.500 in.)1.905
25、 cm(0.750 in.)17.780 cm(7.000 in.)0.277 cm(0.109 in.)O-ring 2017 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3c T 364-5 AASHTO Figure 1aStainless Steel Container and Brass Lid Figure 1bStainless Steel
26、Tower 17.780 cm (7.000 in.)3.256 cm(1.282 in.)1.397 cm(0.550 in.)1.808 cm(0.712 in.)1.270 cm(0.500 in.)1.430 cm(0.563 in.)5.906 cm(2.325 in.)2.540 cm(1.000 in.)0.635 cm(0.250 in.)15.240 cm (6.000 in.)16.510 cm (6.500 in.)16.510 cm(6.500 in.)O-ring1.905 cm(0.750 in.)1.808 cm(0.712)3.810 cm(1.500 in.)
27、3.256 cm(1.282 in.)0.277 cm(0.109 in.)17.780 cm(7.000 in.) 2017 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3c T 364-6 AASHTO Figure 1cLVDT Housing Figure 1dDetailed Drawings of the Central Part of the
28、 Housing in Figure 1c 6.350 cm(2.500 in.)1.930 cm(0.760 in.)1.270 cm(0.500 in.)0.635 cm (0.250 in.)2.858 cm(1.125 in.)2.223 cm(0.875 in.)1.905 cm(0.750 in.)0.277 cm(0.109 in.)3.256 cm(1.282 in.)1.270 cm(0.500 in.)1.155 cm(0.454 in.)6.350 cm(2.500 in.)6.467 cm(2.546 in.)2.210 cm(0.870 in.)2.210 cm(0.
29、870 in.)0.635 cm (0.250 in.)9.525 cm(3.750 in.)0.277 cm(0.109 in.)1.270 cm(0.500 in.)1.905 cm(0.750 in.)O-ring1.270 cm(0.500 in.)0.564 cm(0.222 in.)0.564 cm(0.222 in.)0.660 cm(0.260 in.)0.117 cm (0.046 in.)0.071 cm(0.028 in.)0.071 cm(0.028 in.) 2017 by the American Association of State Highway and T
30、ransportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3c T 364-7 AASHTO Figure 2A Schematic Diagram of the Float System Note 2The container is made of stainless steel 316 (ASTM A182/A182M). The type of brass used for the lid is naval brass (ASTM B21/B21M) (simi
31、lar to admiralty brass), which is 40 percent zinc brass and 1 percent tin. The tower is made of stainless steel 316 (ASTM A182/A182M). The tolerances for all dimensions in Figures 1, 1a, 1b, 1c, and 1d are 0.013 to 0.025 cm (0.005 to 0.01 in.). Note 3The LVDT should have a nominal linear range of 1
32、in. and operating temperature range up to 150C (302F). 4.8. OvenA convection oven with temperature control in the range of 40.0 1.7C (104.0 3.1F) to 100.0 1.7C (104.0 3.1F). 4.9. The combinations of the number of ovens and dilatometers covering minimum to recommended maximum requirements to measure
33、CAE at one level of alkalinity are summarized in Table X1.1. 5. REAGENTS 5.1. Sodium Hydroxide (NaOH)USP or technical grade may be used provided the chemical requirements of Section 5.4 can be met. 5.2. Calcium Hydroxide (Ca(OH)2)USP or technical grade may be used provided the chemical requirements
34、of Section 5.4 can be met. 5.3. WaterDeionized or distilled water is recommended (ASTM D1193). LVDT rodThreaded rodFloat 2017 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3c T 364-8 AASHTO 5.4. Alkaline
35、 SolutionEach liter of solution shall contain 20.0 g (0.044 lb) of NaOH dissolved in 900 ml of water, and shall be diluted with additional deionized or distilled water to obtain 1.0 L (0.26 gal) of solution. Add an additional 1 g (0.0022 lb) of Ca(OH)2per liter in order to saturate the solution. The
36、 final solution is 0.5 0.01N NaOH saturated with Ca(OH)2. Note 4Before using NaOH, review (1) the safety precautions for using NaOH; (2) first aid for burns; and (3) the emergency response to spills, as described in the manufacturers Material Safety Data Sheet or other reliable safety literature. Na
37、OH can cause very severe burns and injury to unprotected skin and eyes. The use of full-face shields, rubber aprons, and gloves impervious to NaOH is recommended. Gloves should be checked periodically for pinholes. 6. SAMPLING AND PREPARATION 6.1. Sample bulk aggregate (ASTM C125) from stockpiles ac
38、cording to T 2. It is recommended to collect aggregates from stockpiles with 1-in. maximum size in order to avoid crushing. However, if any coarse aggregate contains particles with a maximum size 37.5 mm (1.5 in.), then crush using suitable equipment (Section 4.2) material larger than the 37.5-mm (1
39、.5-in.) sieve to pass the 37.5 mm (1.5 in.) sieve. Reduce bulk samples according to R 76. Wash and grade each aggregate sample according to T 11 and T 27. Dry the aggregate samples to constant mass in an oven at 110 1.7C (230 3.1F). A fixed representative gradation is selected for both coarse (M 43
40、and M 80) and fine aggregates (M 6) in order to compare the results between different aggregates. As a result, the oven-dried aggregates need to be sieved out in order to separate the different size fractions (Tables 1 and 2). To prepare a test sample, recombine these size fractions according to the
41、 gradation requirement in Tables 1 and 2 for fine and coarse aggregates, respectively. 6.2. Dry Unit Weight (DRUW)Determine the DRUW (ASTM C125) as defined in T 19 using the test sample prepared in Section 6.1. 6.3. Number of SamplesPrepare three samples for each aggregate to test at three different
42、 temperatures (60, 70, and 80 1.7C (140, 158, and 176 3.1F) with the alkaline solution. Each test sample is around 3.6 to 4.1 kg (8 to 9 lb) depending on the dry unit weight of aggregate. To check repeatability, it is recommended to test three samples for each temperature. Table 1Grading Requirement
43、s for Fine Aggregates Sieve Size Mass, % Passing Retained on 9.5 mm (3/8in.) 4.75 mm (No. 4) 4 0.2 4.75 mm (No. 4) 2.36 mm (No. 8) 13 0.2 2.36 mm (No. 8) 1.18 mm (No. 16) 17 0.2 1.18 mm (No. 16) 600 m (No. 30) 38 0.2 600 m (No. 30) 300 m (No. 50) 23 0.2 300 m (No. 50) 150 m (No. 100) 5 0.2 Table 2Gr
44、ading Requirements for Coarse Aggregates Sieve Size Mass, % Passing Retained on 37.5 mm (1 1/2in.) 25.4 mm (1 in.) 2 0.5 25.4 mm (1 in.) 12.5 mm (1/2in.) 43 0.2 12.5 mm (1/2in.) 4.75 mm (No. 4) 54 0.2 4.75 mm (No. 4) 2.36 mm (No. 8) 1 0.2 2017 by the American Association of State Highway and Transpo
45、rtation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3c T 364-9 AASHTO 7. PROCEDURE 7.1. Determine the weight of the test sample based on the unit weight (Section 6.2) to fill 80 percent of the container volume (3.64.1 kg (89 lb). Add the aggregate sample to the con
46、tainer. 7.2. Add alkaline solution (0.5N NaOH + saturated Ca(OH)2) (see Section 5.4) to the container until the aggregate sample is immersed. For fine aggregates, rodding the aggregate with a metal rod will accelerate penetration of the solution to the bottom of the container. Gently tap the side of
47、 the container to remove any large air bubbles. 7.3. Screw the lid onto the container with the O-ring seated in the groove between the container and lid. Make sure the lid is properly seated and tightened on the container. Screw the tower onto the lid with proper placement of the O-ring. Add more so
48、lution through the tower to the container to ensure that the aggregate sample is fully immersed. 7.4. Place the container-lid-tower assembled system filled with aggregate and solution on the vibrating table and connect the vacuum pump to the tower using a hose and a connector. Turn on the vibrating
49、table and vacuum pump and achieve a vacuum of at least 63.5 cmHg (25 in.Hg) within 5 min (Note 5). Note 5An attainment of the above vacuum is an indication of the leak-proof situation of the container-lid-tower assembled system. If the expected vacuum is not achieved, it possibly indicates some leaking and the following actions: (1) tightening the lid and/or (2) remove the lid followed by rechecking/replacing the O-ring, reassembling, and vacuumin
