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Unformatted text preview: one and near the border of another does not Mince withdrawn 3 remain consistently in one zone but fluctuates between the two. It is therefore, desirable to choose a suitable ratio of fine to coarse aggregate proportions of the concrete to allow some fluctuations in the grading zone of the Ane aggregate. 0.31 The four grading zones indicated in this standard are meant to cover the use of the natural sands available in the country. It is, however, necessary to appreciate the limitations in either using a very coarse sand or a very fine sand and the need to make suitable changes in the mix design. 0.4 Investigations have shown that the bulk density is affected by the size of the container used to determine it. Secondly there is an increasing tendency to batch concrete by weight rather than by volume. Hence as in 1963 version of the standard, the provisions regarding bulk density have not been included. 0.5 Whilst the requirements specified in this standard generally meet the normalrequirements for most of the concrete works, there might be special cases where certain requirements other than those specified in the standard might have to be specified; in such case, such special requirements, the test required and the limits for such tests may be specified by the purchaser. 0.6 Indian Standards Methods of test for aggregates for concrete [IS:2386 (Part I)-1963 to IS: 2386 (Part VIII)-19631 are necessary adjuncts to this standard. For sampling of aggregates, reference may be made to IS : 2430-1969. 0.7 This standard contains clauses 3.2.1, 3.4, 3.5, 6.2, 6.3 and 6.4 which call for agreement between purchaser and supplier and requires the supplier to furnish technical information as given in Appendix A. 0.8 Titles of standards referred are given in Appendix B. to in the various clauses of this standard 0.9 For the purpose of deciding whether a particular requirement of this standard is complied with, the final value, observed or calculated, shall be rounded off in expressing the result of a test or analysis, accordance with IS : Z-1960. The number of significant places retained in the rounded off value should be the same LU that of the specified value in this standard. 1. SCOPE 1.1 This standard covers the requirements for aggregates, crushed or uncrushed, derived from natural sources, such as river terraces and riverbeds, glacial deposits, rocks, boulders and gravels, for use in the Production of concrete for normal structural purposes including mass concrete works. 4 rS : 383 - 1910 1. SCOPE 1.1 ‘Tltis slnndard covers the requirements for aggregates, crushed or un~rusl~d, derived I’rom natural sources, such as river terraces and riverbeds, glacial deposits, rocks, l~oulders and gravels, for use in the production c,l’ concrete for normal structural purposes including mass concrete works. 2. TERMINOLOGY 2.0 For the purpose o> this standard, KIWI.:- A comprchcnsi~v2 ‘s:antlard the following g~1tc.s fur concrctc is under preparation. the tl4nitiun...
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This document was uploaded on 10/01/2013.

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