1、Standard Method of Test for Linear Coefficient of Shrinkage on Cure of Adhesive Systems AASHTO Designation: T 333-07 (2012) American Association of State Highway and Transportation Officials 444 North Capitol Street, N.W., Suite 249 Washington, D.C. 20001 TS-4c T 333-1 AASHTO Standard Method of Test
2、 for Linear Coefficient of Shrinkage on Cure of Adhesive Systems AASHTO Designation: T 333-07 (2012) 1. SCOPE 1.1. This method describes the measurement of the linear coefficient of shrinkage on cure of adhesive systems. 1.2. The values stated in SI units shall be regarded as the standard. 1.3. This
3、 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 the user of this procedure to establish appropriate safety and health practices and to determine the applica
4、bility of regulatory limitations prior to use. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standard: M 235M/M 235, Epoxy Resin Adhesives 3. TERMINOLOGY 3.1. adhesive systema multicomponent material that results in a product used as a bonding material. 3.2. linear coefficient of shrinkagethe measured shrinka
5、ge of a material on cure expressed as change in length divided by the original sample length. 4. SUMMARY OF TEST METHOD 4.1. This method describes the procedure used to measure the change in length following the cure of a fresh cast adhesive material. Test specimens are cast in a half-cylindrical sh
6、aped mold and allowed to cure completely before the linear coefficient of shrinkage is determined. 5. SIGNIFICANCE AND USE 5.1. The reactions that occur when an adhesive system cures generally result in a volume shrinkage of the adhesive specimen. The shrinkage associated with this standard generall
7、y occurs after the gelling phase of the material. The shrinkage is the result of a change in the specific volume, caused by the chemical cross-linking reaction, and a volume change as the cast material cools from its cure temperature or from its maximum reaction temperature. This method does not dif
8、ferentiate between these two effects. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4c T 333-2 AASHTO 5.2. The effects of the mold walls further complicate the measurement of shrinkage. As the react
9、ing system gives off heat, it normally expands. Most of the expansion must take place toward the open side of the mold. When the maximum reaction temperature has passed, the solidifying adhesive should shrink uniformly in all directions. However, friction prevents the free movement of the adhesive o
10、ver the mold surfaces, allowing the greatest shrinkage to occur perpendicular to the open surface of the mold. 5.3. Usually the end user is concerned only with deviations from mold dimensions. It can be assumed that shrinkage perpendicular to surfaces other than the open side will be uniform and pro
11、portional to the distance over which the shrinkage occurs. Thus, the measurement of shrinkage in length, the linear shrinkage, when expressed in units such as centimeters shrinkage per centimeter of length (cm/cm) or inches per inch (in./in.), gives a value characteristic of the adhesive. This value
12、 is useful in predicting the behavior of the adhesive in molds of other shapes and sizes. 6. APPARATUS 6.1. MoldThe mold shall be composed of a material, such as cold -rolled steel, that will not significantly distort during testing and will regain its original dimensions after cure. The mold shall
13、be 25.400 0.125 cm (10.00 0.05 in.) in length and have an internal radius of 1.270 0.125 cm (0.50 0.05 in.). The wall of the mold shall be 0.630 0.125 cm (0.25 0.05 in.) thick. It will have a removable end plate on each end (Figure 1). Figure 1Mold 6.2. Mineral Oil. 6.3. Film Linersuitable for linin
14、g the mold, approximately 0.025 mm (0.001 in.) in thickness. Polytetrafluoroethylene or polyethylene films have been found acceptable. 6.4. Micrometercapable of reading to the nearest 0.0025 mm (0.0001 in.). 6.5. Temperature-Recording Deviceaccurate to the nearest 1 C (2F). 7. SAMPLING 7.1. The samp
15、ling shall be done in accordance with Section 10 of M 235M/M 235. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4c T 333-3 AASHTO 8. PREPARATION OF TEST SPECIMENS 8.1. Measure and record the length
16、of the mold. 8.2. Wipe all interior surfaces of the mold with a thin film of mineral oil, and apply the film liner described in Section 6.3 to these surfaces, ensuring a smooth surface and taking care to remove all wrinkles. 8.3. Condition the mold and the individual components of the system for at
17、least 4 h at 23 1C (73 2F). 8.4. Mix the components, taking care to minimize the entrapment of air since air inclusions affect the shrinkage characteristics. 8.5. Fill the mold with the mixed adhesive, taking care to avoid air entrapment. If the adhesive is a material that cures at room temperature,
18、 pour the mixture before the temperature exceeds 30C (86F). 8.6. Cure the casting in the mold at 23 1C (73 2F) for the cure time stated in the manufacturers instructions. 8.7. Record the maximum reaction temperature of the material in cure using a suitable temperature-recording device in the geometr
19、ic center of the reacting mass. 9. CONDITIONING 9.1. After casting and curing, condition the test specimen at 23 1C (73 2F) and 50 5 percent relative humidity for not less than 40 h prior to testing. 9.2. Conduct tests in the standard laboratory atmosphere of 23 2C (73.4 3.6F) and 50 5 percent relat
20、ive humidity, unless otherwise specified. 10. PROCEDURE 10.1. Following conditioning, remove the specimen from the mold by removing the end plates. The film liner may be removed at this time if necessary for accurate measurements. 10.2. Replace one end plate on the mold and return the specimen to th
21、e mold in the same position in which it was prior to removal. 10.3. Making sure that the specimen is in direct contact with the end plate, determine with a micrometer the change in length of the specimen with reference to the mold length. Record four readings spaced across the open end of the mold.
22、Average the four readings and report as the change in length of the specimen. 11. CALCULATION OF RESULTS 11.1. Calculate the linear coefficient of shrinkage in centimeters per centimeter (or inches per inch) as follows: linear coefficient of shrinkage = (A 2B)/C (1) 2015 by the American Association
23、of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4c T 333-4 AASHTO where: A = change in length, cm (in.); B = film thickness, if removed from the sample; and C = inside mold length, cm (in.). 12. REPORT 12.1. Report the following info
24、rmation: 12.1.1. Size of the mold used; 12.1.2. Volume of the casting; 12.1.3. Ambient test temperature; 12.1.4. Maximum reaction temperature; 12.1.5. Conditions of cure of the specimen, if other than standard; and 12.1.6. Linear coefficient of shrinkage expressed in centimeters of shrinkage per cen
25、timeter of specimen length (or inches per inch). 13. PRECISION AND BIAS 13.1. PrecisionThe research required to develop precision values has not been conducted. 13.2. BiasThe research required to establish the bias of the method has not been conducted. 14. KEYWORDS 14.1. Adhesive system; cure; epoxy; epoxy cure; epoxy shrinkage; linear coefficient; linear coefficient of epoxy; linear coefficient of shrinkage; resin adhesive shrinkage; shrinkage. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.
