AASHTO PP 89-2018 Standard Practice for Grinding the Ends of Cylindrical Concrete Specimens.pdf

1、Standard Practice for Grinding the Ends of Cylindrical Concrete Specimens AASHTO Designation: PP 89-181Technical Section: 3c, Hardened Concrete Release: Group 1 (April) American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001

2、TS-3c PP 89-1 AASHTO Standard Practice for Grinding the Ends of Cylindrical Concrete Specimens AASHTO Designation: PP 89-181 Technical Section: 3c, Hardened Concrete Release: Group 1 (April) 1. SCOPE 1.1. This practice describes the process of grinding the ends of cylindrical concrete specimens to a

3、 planar surface in order for them to be tested for compressive strength using AASHTO T 22, ASTM C39/C39M, or any other standard that permits grinding the ends of cylindrical concrete specimens to a planar surface prior to testing for compressive strength. 1.2. This practice is limited to automated o

4、r semi-automated mechanical wet-grinding processes that can accommodate the grinding of multiple specimens in a consistent manner. 1.3. The values stated in SI units or inch-pound units are to be regarded separately as the standard. Within the text, the inch-pound units are shown in brackets. The va

5、lues stated in each system are not exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard. 1.4. This standard may involve hazardous materials, operations, or equipment. This standard doe

6、s 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 determine the applicability of regulatory limitations prior to use. Note 1The safety precautions given

7、in the Manual of Aggregate and Concrete Testing, located in the Related Materials section of Volume 04.02 of the Annual Book of ASTM Standards, are recommended. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: R 18, Establishing and Implementing a Quality Management System for Construction Materials T

8、esting Laboratories R 39, Making and Curing Concrete Test Specimens in the Laboratory T 22, Compressive Strength of Cylindrical Concrete Specimens T 23, Making and Curing Concrete Test Specimens in the Field T 24M/T 24, Obtaining and Testing Drilled Cores and Sawed Beams of Concrete T 231, Capping C

9、ylindrical Concrete Specimens 2.2. ASTM Standards: C31/C31M, Standard Practice for Making and Curing Concrete Test Specimens in the Field 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-3c PP 89-2 AA

10、SHTO C39/C39M, Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens C42/C42M, Standard Test Method for Obtaining and Testing Drilled Cores and Sawed Beams of Concrete C192/C192M, Standard Practice for Making and Curing Concrete Test Specimens in the Laboratory C617/C617M,

11、Standard Practice for Capping Cylindrical Concrete Specimens C1231/C1231M, Standard Practice for Use of Unbonded Caps in Determination of Compressive Strength of Hardened Concrete Cylinders R0030, Manual of Aggregate and Concrete Testing, Annual Book of ASTM Standards, Vol. 04.02 3. SIGNIFICANCE AND

12、 USE 3.1. This practice can be used to prepare cylindrical concrete specimens of any anticipated strength, including high-strength concrete, for compressive strength testing. 3.2. The use of this practice eliminates the need to use other practices for capping, including T 231or C617/C617M, or the us

13、e of unbonded caps in accordance with C1231/C1231M. 3.3. This practice is intended to be used on molded cylindrical concrete specimens after curing if the specimens were removed from molds following R 39, T 23, ASTM C31/C31M, or ASTM C192/C192M. 3.4. This practice is intended to be used on cored cyl

14、indrical concrete specimens prior to storing or curing as required in T 24M/T 24 or ASTM C42/C42M. 4. APPARATUS 4.1. Mechanical GrinderAn automated or semi-automated wet-grinding machine that can grind the ends of several cylinders at one time in conformance with this standard and the compressive st

15、rength test method used to test the cylindrical concrete cylinders. 4.2. StraightedgeA stiff steel bar that is greater than the diameter of the cylindrical concrete test specimen and is plane within 0.025 mm (0.001 in.). 4.3. Glass PlateA glass plate that is large enough to check the planeness of th

16、e straightedge over the entire length of the straightedge at one time. 4.4. Feeler GaugesA 0.050 mm (0.002 in.) thin steel measurement device for checking the planeness of the ends of the cylindrical concrete specimens and a 0.025 mm (0.001 in.) thin steel measurement device for checking the planene

17、ss of the straightedge. 5. EQUIPMENT CHECKS AND MAINTENANCE 5.1. The thickness of the feeler gauges specified in Section 4.4 shall be checked for conformance before being placed into service and whenever there is doubt about conformance. Ensure that the thickness of the feeler gauge is no thicker th

18、an the thickness specified in Section 4.4. Document and retain a record of the check in accordance with R 18 requirements. 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-3c PP 89-3 AASHTO 5.2. The s

19、traightedge shall be checked for conformance to the requirements of Section 4.2 every twelve months, and when there is doubt about the planeness of the straightedge, by placing the straightedge against the glass plate specified in Section 4.3 and sliding the feeler gauge specified in Section 4.4 alo

20、ng the edge. If the feeler gauge penetrates the space between the glass plate and straightedge at any time, the straightedge shall be replaced or machined to conform to the requirements of Section 4.2 before placing the straightedge back in service. Document and retain a record of the check in accor

21、dance with R 18 requirements. 5.3. Establish, document, and regularly perform a procedure for maintenance of the grinder. Conduct grinder maintenance at least once every twelve months. Document and retain the maintenance schedule, procedure, and records in accordance with R 18 requirements. Note 2Us

22、ers of this standard are encouraged to follow manufacturers recommendations for maintenance of the grinder including regularly scheduled replacement of grinding or wearing parts, cleaning, and lubrication of moving parts as needed. 6. PROCEDURE 6.1. Obtain the cylindrical concrete test specimens onc

23、e they have been formed, demolded, and cured in accordance with R 39, T 23, ASTM C31/C31M, or ASTM C192/C192M or cored in accordance with T 24M/T 24 or ASTM C42/C42M. 6.2. Brush any loose debris from the ends of the cylindrical concrete specimens. 6.3. Clamp or otherwise mount the cylindrical concre

24、te specimens into the grinding machine. 6.4. Following the manufacturers instructions, grind one end of the cylindrical concrete specimens until the end is plane to 0.05 mm (0.002 in.). Follow the manufacturers instructions for grinding the opposite end of the cylindrical concrete specimens. 6.4.1.

25、Depending on the design of the machine, the cylindrical concrete specimens may need to be unclamped or dismounted and rotated so that the opposite end may be ground. Other machines may reorient the cylindrical concrete specimens to automatically grind the opposite end. 6.5. After both ends of the cy

26、linders in the machine have been ground, verify the planeness of the ends by holding the plane side of the straightedge along the surface of the end of the cylindrical concrete specimen. Attempt to slide the feeler gauge thickness under the straightedge covering the entire diameter of the surface of

27、 the end. Rotate the straightedge 90 degrees, and attempt to slide the feeler gauge thickness under the straightedge covering the entire diameter of the surface of the end. Repeat the verification process on the other end of the specimen. 6.5.1. If either end of the cylinder is found to not be plane

28、 to 0.05 mm (0.002 in.), repeat the grinding process until planeness can be obtained without decreasing the length of the cylindrical concrete specimen beyond the length requirements for T 22, T 24M/T 24, ASTM C39/C39M, or ASTM C42/C42M, or client specifications. 6.6. If the specimen was molded in a

29、ccordance with R 39, T 23, ASTM C31/C31M, or ASTM C192/C192M, determine the compressive strength of the molded cylindrical concrete specimens in accordance with T 22 or ASTM C39/C39M. If the specimen was cored in accordance with T 24M/T 24 or ASTM C42/C42M, follow the requirements for moisture condi

30、tioning prior to compressive strength testing in accordance with T 24M/T 24 or ASTM C42/C42M. 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-3c PP 89-4 AASHTO 7. KEYWORDS 7.1. Compressive strength; drilled cores; planeness; wet grinding. 1This provisional standard was first published in 2018. 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.