ASTM C39/C39M-20 pdf free.The title is Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens.
ASTM C39/C39M covers determination of compressive strength of cylindrical concrete specimens such as molded cylinders and drilled cores. It is limited to concrete having a density in excess of 800 kg/m3 [50 lb/ft3].
3. Terminology
3.1 Definitions—For definitions of terms used in this prncticc, refer to Terminology C 125.
3.2 Definitions of Terms Specific to This Standard.
3.2. 1 bearing block, n—steel piece to distribute the load from the testing machine to the specimen.
3.2.2 lower bearing block, n—steel piece placed under the spimcn to distribute the load from the testing machine to the specimen.
3.2.2.1 Discussion—The lower hearing block provides a readily machinable surface for maintaining the specified bearing surface. The lower bearing block may also be used to adapt the testing machine to various specimen heights. The lower bearing block is also referred to as botioni block, plain block. and false platen.
3.2.3 platen, n—primary bearing surface of the testing machine.
3.2.3.1 Discussion—The platen is also referred to as the testing machine table.
3.2.4 spacer, n—steel piece used to elevate the lower bearing block to accommodate test specimens of various heights.
3.2.4.1 Discussion—Spacers are not required to have hardened bearing faces because spacers are not in direct contact with the specimen or the retainers of unbonded caps.
3.2.5 upper hearing block, n—steel assembly suspended above the specimen that is capable of tilting to hear uniformly on the top of the specimen.
3.2.5.1 Discussion—The upper bearing block is also referred to as the spherica liv seated block and the suspended block.
4. Summary of Test Method
4.I This test method consists of applying a compressive axial load to molded cylinders or cores at a rate which is within a prescribed range until failure occurs. The compressive strength of the specimen is calculated by dividing the maxi mum load attained during the test by the cross-sectional area of the specimen.
6. Apparatus
6.1 Tesriiig Machine—The testing machine shall be of a type having suflicient capacity and capable of providing the rates of loading prescribed in 8.5.
6.1.1 Verify the accuracy of the testing machine in accordance with Practices E4, except that the verilied loading range shall be as required in 6.4. Verification is required:
6.1.1.1 Within 13 months of the last calibration.
6.1.1.2 On original installation or immediately after relocation.
6.1.1.3 Immediately after making repairs or adjustments that aliect the operation of the force applying system or the values displayed Ofl the load indicating system. except for zero adjustments that compensate for the mass of bearing blocks or specimen, or both, or
6. 1.1.4 Whenever there is reason to suspect the accuracy of the indicated loads.ASTM C39/C39M-20 pdf free download.