Unformatted text preview: nds per square
inch). On other concrete work, tests may be required for the concrete and other materials from time to
time to determine whether wuch materials or methods of use are such as to produce concrete of the
quality specified and used in accordance with the design of the building or structure. When tests are
required, each class of concrete shall be represented by at least five tests (10 speciments). Two
specimens shall be made for each 100 cubic meters (130 for each day's concreting. The required number
of tests may be modified for jobs involving less than 100 cubic meters (130 cubic yards). All such tests
shll be made by an approved agency, and copies of the results shall be submitted to the Owner or his
duly authorized representative. Speciment for concrete cylinder tests shall be taken at the place where
the concrete is being deposited and shall be taken and cured in accordance wtih the requirements set
forth in ASTM Specification C31 and tested in accordance with the requirements set for in ASTM
Specification C39. samples from which compression test specimens are molded shall be secured in
accordance with or as a basis for acceptance of concrete shall be made and laboratry-cured in accordance
with ASTM Specification C31. Additional test specimens cured entirely under field conditions may be
required to check the adequacy of curing and protection of the concrete. Strength tests shall be made in
accordance with ASTM Specification C39.
The age for strength tests shall be 28 days or, where specified, the earlier age at which the concrete is
to receive its full load or maximum stress. Additonal tests may be made at earlier ages to obtain advance
information on the adequacy of strength development where age-strength relationships have been
established for the materials and proportions used.
To conform to the requirements of this chapter: 1. For structures designed in accordance with the working stress design mehtod of the chapter,
the average of any five consecutive strength tests of the laboratory-cured speciments representing
each class of concrete shall be equal to or greater than the specified strength, fc, and not more
than 20 per cent of the strength tests shall have values less than the specified strength.
2. For structures designed in accordance with the ultimate strength design method of this
chapter, and for pre-stressed structures the average of any three consecutive strength tests of the
laboratory-cured speciments representing each class of concrete shall be equal to or greater than
the specified strength, fc, and not more than 10 per cent of the strength tests shall have values
less than the specified strength.
When it appears that the laboratory-cured speciments will fail to conform to the requirements for
strength, theEngineer shall have the right to order changes in the concrete sufficient to increase the
strength to meet these requirements. the strengths of any specimens cured on the job are intended to
indicate the adequacy of...
View Full Document
- Fall '12
- Building code, Building officials