The Grading of Fine Aggregate may be specified in the ‘Max. aggregate size’ field on a Mix Design Form, unless either aggregate details from the Laboratory Measurements Dialog or the results entered on a Trial Mix Dialog are being used in the mix design.
The DOE method as amended in 1988, classifies fine aggregate gradings for the purposes of concrete mix design according to the percentage of the fine aggregate, which passes a 600[[m (ASTM no. 30) sieve, and this method of classification is used in Firtstmix.
The ACI211.1-9, whose recommendations for concrete mix design are widely used in the USA and elsewhere, uses a fineness modulus to describe the grading of the fine aggregate. The fineness modulus is defined in ASTM C 136 (see References 24) as the sum of the cumulative proportions of the aggregate retained on the standard series of sieves up to the size of sieve, which retains none of the aggregate.
Both the DOE Method’s classification and the fineness modulus give a measure of the extent to which the finer particles predominate in a particular fine aggregate.
The grading of the fine aggregate influences the percentage of fine aggregate, which is needed to achieve a given workability. If the percentage of fine aggregate is specified, the grading is not used in the mix design.
If the Laboratory Measurements Dialog is used to specify the aggregate properties, Firstmix calculates the grading of the fine aggregate from the sieve percentages. Since the grading of the fine aggregate influences the workability, it is the volumetric percentage passing a 600[[m sieve that is significant, rather than the percentage by weight, and this is therefore calculated.
If trial mix results are used in a mix design, Firstmix calculates a nominal grading of fine aggregate, which matches the trial mix results according to the assumptions of the DOE method.
Range: 15 - 100 %