1、Standard Method of Test for Tensile Strength of Hydraulic Cement Mortars AASHTO Designation: T 132-87 (2013)1American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-3a T 132-1 AASHTO Standard Method of Test for Tensile Str
2、ength of Hydraulic Cement Mortars AASHTO Designation: T 132-87 (2013)11. SCOPE 1.1. This method covers determination of the tensile strength of hydraulic cement mortars employing the briquet specimen. It is primarily for use by those interested in research on methods for determining tensile strength
3、 of hydraulic cement. 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 the user of this standard to consult and establish appropriate safety and hea
4、lth practices and determine the applicability of regulatory limitations prior to use. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: M 85, Portland Cement M 92, Wire-Cloth Sieves for Testing Purposes T 129, Amount of Water Required for Normal Consistency of Hydraulic Cement Paste 2.2. ASTM Standards
5、: C670, Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials C778, Standard Specification for Standard Sand C1005, Standard Specification for Reference Masses and Devices for Determining Mass and Volume for Use in the Physical Testing of Hydraulic
6、 Cements Manual of Cement Testing, Annual Book of ASTM Standards, Volume 04.01. 3. SIGNIFICANCE AND USE 3.1. Researchers in the field of hydraulic cement have recognized the need for improved tensile strength. This method allows for the determination of tensile strength of a hydraulic cement mortar
7、by casting and testing briquet specimens. It is recommended that the tester be familiar with this method in order to obtain the best possible accuracy and precision. 3.2. Table 1 contains minimum tensile strength values, which are stated limits in M 85 for portland cement. The user of this method ma
8、y be interested in comparing research results with these values when briquets composed of one part cement to three parts standard sand have been made. These values may not be appropriate for comparison when different proportions or proportions involving other than standard sand have been used. 2016
9、by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3a T 132-2 AASHTO Table 1Tensile Strengtha Cement Type I II III IV V 1 day in moist air, psi (kPa) 275 (1,896) 1 day in moist air, 2 days in water, psi (kPa)
10、 150 (1,034) 125 (862) 375 (2,586) 1 day in moist air, 6 days in water, psi (kPa) 275 (1,896) 250 (1,724) 175 (1,207) 250 (1,724) 1 day in moist air, 27 days in water, psi (kPa) 350 (2,413) 325 (2,241) 300 (2,068) 325 (2,241) a Taken from M 85-70 without change. 4. APPARATUS 4.1. Weights and Weighin
11、g DevicesThe weights and weighing devices shall conform to the requirements of ASTM C1005. The weighing devices shall be evaluated for precision and accuracy at a total load of 1000 g or 2000 g, as applicable. 4.2. SievesSquare-hole, woven wire cloth, No. 20 (850-m) and No. 30 (600-m) sieves conform
12、ing to M 92. 4.3. Glass GraduatesGlass graduates of suitable capacities (preferably large enough to measure the mixing water in a single operation) shall be made to deliver the indicated volume at 68F (20C). The permissible variation shall be 1.0 mL. These graduates shall be subdivided to at least 1
13、 mL, except that the graduation lines may be omitted for the lowest 5 mL for 100- and 150-mL graduates and for the lowest 10 mL for a 200-mL graduate. The main graduation lines shall be circles and shall be numbered. The least graduations shall extend at least one seventh of the way around the cylin
14、der, and intermediate graduations shall extend at least one fifth of the way around. 4.4. Briquet MoldsThe molds for making test specimens shall be made of metal not attacked by the cement mortar and shall have sufficient material in the sides to prevent spreading during molding. Gang molds, when us
15、ed, shall be of the type shown in Figure 1. The dimensions of the briquet molds shall conform to the following requirements: width of mold, between inside faces, at waist line of briquet, 25 mm (1 in.) with permissible variations of 0.25 mm (0.01 in.) for molds in use and 0.13 mm (0.005 in.) for new
16、 molds; thickness of molds measured at the point of greatest thickness on either side of the mold at the waist line, 25 mm (1 in.) with permissible variations of +0.10 mm (0.004 in.) and 0.05 mm (0.002 in.) for new molds and 0.5 mm (0.02 in.) for molds in use. The briquet test specimens shall confor
17、m to the dimensional requirements shown in Figure 2. Figure 1Briquet Gang Mold 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3a T 132-3 AASHTO Figure 2Briquet Specimen for Tensile Strength Test 4.5.
18、 TrowelThe trowel shall be of a convenient size and have a steel blade 100 to 150 mm (4 to 6 in.) long. 4.6. Testing MachineThe testing machine shall be capable of applying the load continuously at a rate of 600 25 lbf (2.67 0.11 kN) min, with provision for adjustments of the rate of loading. The re
19、quirements for accuracy of the testing machine shall be as follows: The error for loads of not less than 100 lbf (445 N) shall not exceed 1.0 percent for a new machine, or 1.5 percent for a used machine. The testing machine shall be calibrated frequently to determine its accuracy. (See Note 1.) Note
20、 1For instructions relating to the manner and frequency of calibration of the testing machine, see Section 40 of the Manual of Cement Testing. 4.7. ClipsThe clips for holding the tension test specimens shall be in accordance with Figure 3 and Table 2. Note: 1 in. = 25.4 mm1 0.02“3“1.5“12“3 4“10“1.32
21、“134“Rad1 2“Rad 134“ 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3a T 132-4 AASHTO Figure 3Clips for Briquet Testing Machine Note: To be cast of manganesebronze or other equallysuitable noncorrosi
22、vematerial.Detail “1” CastingDrill and tap forPin5/16 Dia24 THD SAE StdDrill for3/8 bolt11/49/161Drill Hole inassembly for3/8bolt“f ” all over1/2 DiaForceFit5/1611/815/1613/1611/4 Rollersparallelwithin0.020.02between facesof rollersDrill and tapfor screws#10-24 ASME7/16 deepA B7/165/83/4Details “2”
23、and “3”Detail “7”Drill and C sinkfor #10 screwsASME“f ” all over“f ” all over7/1621/81/215/167/161/41/27/87/845/8 R113/16R5/16R1201/41/41/41/417/827/81/85/815/3239/1619/16211/815/825/821/4115/16Detail “5” Detail “6”1/415/85/16DiaSAE std24 TPIReam turningfit5/16pin #611/2Easy turningfit in clip1/20.0
24、11/2AssemblyViewNote: Portion below Line AB is standard. As shownherein, portion above Line AB is designed foruse on one type of machine and may be variedto adapt to other machines.Note: 1 in. = 25.4 mm 2016 by the American Association of State Highway and Transportation Officials.All rights reserve
25、d. Duplication is a violation of applicable law.TS-3a T 132-5 AASHTO Table 2Clip for Briquet Testing Machine No. Name Reqd. Matl. Remarks 1 Clip 2 * * See Detail 2 Pivot Block 2 * * Manganese Bronze 3 Pivot 2 Steel Case-Hardened 4 Sq. Hd. Bolt, Hex. Nut 2 M.S. 3/8in. Std. 31/2in. long 5 Roller 4 * *
26、Stainless Steel 6 Pin 4 * *Stainless Steel 7 Guide 2 * *Stainless Steel 8 Flat Head Mach. Scr. 4 Brass #10-24 THD ASME 5. STANDARD SAND 5.1. The sand used for making test specimens (see Section 8.1) shall be natural silica sand conforming to the requirements for 2030 standard sand as described in AS
27、TM C778. 6. TEMPERATURE AND HUMIDITY 6.1. The temperature of the air in the vicinity of the mixing slab, the dry materials, molds, and base plates shall be maintained between 68 and 81.5F (20 and 27.5C). The temperature of the mixing water, moist closet or moist room, and water in the briquet storag
28、e tank shall not vary from 73.4F (23C) by more than 3F (1.7C). 6.2. The relative humidity of the laboratory shall be not less than 50 percent. The moist closet or moist room shall be so constructed as to provide storage facilities for test specimens at a relative humidity of not less than 95 percent
29、. 7. NUMBER OF BRIQUETS 7.1. Three or more briquets shall be made for each period of test specified. 8. PROCEDURE 8.1. Proportioning, Consistency, and Mixing of Mortars: 8.1.1. The proportions of the standard mortar shall be one part cement to three parts standard sand by weight. The quantities of d
30、ry materials to be mixed at one time in the batch of mortar shall be no less than 1000 nor more than 1200 g for making six briquets and no less than 1500 nor more than 1800 g for making nine briquets. The percentage of water used in the standard mortar shall depend upon the percentage of water requi
31、red to produce a neat cement paste of normal consistency from the same sample of cement and shall be as indicated in Table 3, the values being in percentage of the combined dry weights of the cement and standard sand. Determine the percentage of water required to produce a neat cement paste of norma
32、l consistency in accordance with T 129. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3a T 132-6 AASHTO Table 3Percentage of Water for Standard Mortars Water for Neat Cement Paste of Normal Consiste
33、ncy, % Water for Mortar of One Part Cement to Three Parts Standard Sand, %a15 9.0 16 9.2 17 9.3 18 9.5 19 9.7 20 9.8 21 10.0 22 10.2 23 10.3 24 10.5 25 10.7 26 10.8 27 11.0 28 11.2 29 11.3 30 11.5 aWhen the proportions of cement to sand are other than one to three by weight, the amount of mixing wat
34、er shall be calculated from the following formula upon which Table 3 is based: 231PyKn= +where: y = water required for the sand mortar, percent; P = water required for neat cement paste of normal consistency, percent; n = number of parts of sand to one of cement by weight; and K = a constant which f
35、or the standard sand has the value 6.5. Note 2Other proportions involving the use of graded sand, silica flour, or other similar materials may also be used to develop meaningful research information. 8.1.2. Weigh the dry materials, place them upon a smooth nonabsorbent surface, thoroughly mix dry, a
36、nd form a crater in the center. Pour the proper percentage of clean water into the crater, and turn the material on the outer edge into the crater within 30 s by the aid of a trowel. After an additional interval of 30 s for the absorption of the water, during which interval lightly trowel the dry mo
37、rtar around the outside of the cone over the remaining mortar to reduce the evaporation losses and to promote absorption, complete the operation by continuous, vigorous mixing, squeezing, and kneading with the hands for 11/2min. During the operation of mixing, protect the hands with snug-fitting rub
38、ber gloves. 8.2. Molding Test Specimens: 8.2.1. Before being filled, thinly cover the molds with a film of mineral oil. Immediately following completion of mixing the mortar, and with the molds resting on unoiled glass or metal plates, fill the molds heaping full without compacting. Then press the m
39、ortar in firmly with the thumbs, applying the force twelve times to each briquet, at points to include the entire surface. The force shall be such that the simultaneous application of both thumbs will register a force of 15 to 20 lbf (67 to 89 N). Maintain each application of the thumbs not longer t
40、han sufficient to attain the specified force. Heap the mortar above the mold and smooth it off with a trowel. Draw the trowel over the mold in such a manner as to exert a force of not more than 4 lbf (17.8 N). Cover the mold with a plane glass or metal plate oiled with mineral oil, and turn over the
41、 mold and plates (held 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3a T 132-7 AASHTO together with the hands), rotating the mold about its longitudinal axis. Remove the top plate and repeat the op
42、eration of heaping, thumbing, and smoothing off. Use no ramming or tamping, nor any troweling in excess of that required to smooth off the specimen. 8.3. Storage of Test Specimens: 8.3.1. Keep all test specimens, immediately after molding, in the molds on the base plates in the moist closet or moist
43、 room for from 20 to 24 h with their upper surfaces exposed to the moist air but protected from dripping water. If removed from the molds before 24 h, keep them on the shelves of the moist closet or moist room until they are 24 h old, and then immerse the specimens, except for those for the 24-h tes
44、t, in saturated lime water in storage tanks constructed of noncorroding materials. Keep the storage water clean by changing as required. 8.4. Determination of Tensile Strength: 8.4.1. Test the briquet specimens immediately after their removal from the moist closet for 24-h specimens, and from storag
45、e water for all other specimens. Break all test specimens for a given test age within the permissible tolerance prescribed in the following table: Test Age Permissible Tolerance 24 h 1/2h 3 days 1 h 7 days 3 h 28 days 12 h If more than one specimen at a time is removed from the moist closet for the
46、24-h tests, cover these briquets with a damp cloth until time of testing. If more than one specimen at a time is removed from the storage water for testing, place these briquets in a pan of water at a temperature of 73.4 3F (23 1.7C) and of sufficient depth to completely immerse each briquet until t
47、ime of testing. 8.4.2. Wipe each briquet to a surface-dry condition, and remove any loose sand grains or incrustations from the surfaces that will be in contact with the clips of the testing machine. The bearing surfaces of the clips shall be clean and free of sand, and the roller bearings shall be
48、well oiled and maintained so as to ensure freedom of turning. Keep the stirrups supporting the clips free of accumulations, and keep the pivots in proper adjustment so that the clips may swing freely on the pivots without binding in the stirrups. Carefully center the briquets in the clips and apply
49、the load continuously at the rate of 600 25 lbf (2.67 0.11 kN)/min. 9. FAULTY BRIQUETS AND RETESTS 9.1. Briquets that are manifestly faulty, or that give strengths differing by more than 15 percent from the average value of all test briquets made from the same sample and tested at the same period, shall not be considered in determining the tensile strength (see Note 3). After discarding briquets or strength va
