These standards reflect the expert opinion of researchers, concrete masonry manufacturers, designers, contractors and others with an interest in quality standards for concrete masonry. Consequently, concrete masonry units chosen for testing should be randomly sampled. Choosing units from one portion of a pallet, or choosing the most or least desirable units may misrepresent the properties of the lot. Although a shipment may consist of several different unit configurations, samples for testing should all have the same configuration and dimensions. Sampled units are marked with a unique identification and weighed.
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NOTE A1. It is a useful reference value, but it is not a requirement of unit specifications. This value is not comparable to the definition of a solid unit in C90 and C, which refers to the net cross-sectional area of every plane parallel to the bearing surface relative to the gross cross-sectional area of the same plane.
Determine the maximum variation for the set by identifying the maximum of the nine values. No further reproductions authorized. The resulting specimen shall have no projections or irregular features and cores shall be fully enclosed. The compressive strength of the segment shall be considered to be the compressive strength of the whole unit. If full-size units are not within that dimensional ratio requirement, the units shall be saw-cut to produce a compression test specimen with that dimensional ratio prior to capping.
The height of the compression specimen shall be greater than or equal to 2 in. NOTE A2. This value is not comparable to the definition of a solid unit in C55 and C, which refers to the net cross-sectional area of every plane parallel to the bearing surface relative to the gross cross-sectional area of the same plane. When freeze-thaw durability testing is required, a set shall consist of a minimum of five full-size units.
If lips or similar projections are present, the projection shall be ignored and the height measurements taken from the bearing surface behind or in front the projection on the main bearing surface of the unit see Fig.
NOTE A3. The coupon width shall be as close to 2 in. Coupon dimensions shall not differ by more than 0. The compressive strength of the coupon shall be considered to be the compressive strength of the whole unit. Saw-cutting shall be performed in accordance with 7. Due to the variety of unit configurations available, it is not possible to specify exact locations for obtaining coupons. In order to compare results within a set or between independently performed tests, coupons should be consistently obtained from the same location for a given unit configuration.
Suppliers should be consulted for the recommended coupon sample location for a given unit configuration. Record the load as indicated to the nearest 10 lb [50 N] or the minimum resolution of the test machine as used during testing, whichever is greater. See Fig. If full size units do not comply with all of the requirements of A4. If the smoothness or the aspect ratio required in FIG.
If saw-cutting is required to achieve specimen size or configuration requirements in A4. Verify the accuracy of cut by measuring and recording as Tc the thickness of the cut specimen at mid-length of each side. Discard any specimen if the difference in Tc at the two different points is greater than 0. Calculate the difference in thickness for each point and divide by 2 to determine the calculated cap thickness at each point.
Calculate the average cap thickness for the whole specimen by taking the average of the calculated cap thickness at each of the two points. NOTE A4. Based on Eq A4. Required Accuracy 0. If absorption tests are performed on specimens other than fullsize units, report the reason for testing reduced-size units.
NOTE A5. There are many other shapes and sizes of grid paving units available which may require different procedures for measuring and obtaining specimens. Suppliers should be consulted for recommended specimen sampling procedures. Record the minimum value measured. For the web with the minimum thickness, measure and record two additional web readings.
The two additional readings shall be at the maximum width of the web and at mid-height of the web. Measure and record all web width measurements to the nearest division required to be reported. Disregard grooves, scores, and similar details in the measurements.
Specimens shall be full-sized units or reduced-size units as modified in A5. The resulting specimen shall be symmetrical, have no projections or irregular features, and shall be a fully enclosed cell or cells.
When compression specimens are other than full-size units, absorption testing shall be performed on specimens saw-cut from full-size units with the same configuration as the reducedsize compression specimens.
For determination of net area, absorption, and density, use data collected from testing in accordance with A5. Each specimen shall consist of a strip of paver with specimen height equal to specimen width. The length of the specimen shall be equal to the length of the unit or 8 in.
Where a unit contains supporting ribs, obtain specimens by cutting perpendicular to the direction of the ribs so as to avoid inclusion of beveled or recessed surfaces at top or bottom edges see Fig. The load from the upper bearing block of the testing machine shall be applied through the centroid of the concrete roof paver by the bearing assembly illustrated. The flexural length of the paver unit is taken as the end-to-end plan dimension of the units.
Loading shall be applied at a uniform rate such that the total load is applied in not less than 1 min and not less than 3 min. The coupon width shall in no case be less than 1. NOTE A7. In order to compare results within a set or between A7.
If the upper platen includes a nonspherical section that was manufactured integrally with the spherical head from a single piece of steel, the diameter of the upper platen is considered to be the diameter of the spherical seat on the upper surface of the upper platen plus the thickness of the nonspherical section tPL. However, the diameter of the upper platen shall not be greater than the minimum horizontal dimension of the upper platen.
Record this distance as Z. These samples were developed for use in recording and reporting test information for conventional concrete masonry units to determine their compliance with Specification C These forms are to be used as guidelines only.
Users of these test methods may use or modify these forms to suit their purposes and to address the requirements of the test methods as they apply to the specific specimens being tested. These forms meet all of the requirements of A4. July 1, 1 The procedure for absorption in 8. Approved December 15, 1 Deleted 5. Approved July 1, 1 Revised A4. ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard.
Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn.
Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM International Headquarters.
Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, at the address shown below.
These ASTM standards contain minimum requirements that assure properties necessary for quality performance. These requirements include items such specified component materials, compressive strength, permissible variations in dimensions, and finish and appearance criteria. Currently, seven ASTM standards apply to units intended primarily for construction of concrete masonry walls, beams, columns or specialty applications see Table 1. The letter and first number of an ASTM designation is the fixed designation for that standard.
SAMPLING AND TESTING CONCRETE MASONRY UNITS