Concrete, a crucial building material, relies on aggregates for its various properties, including workability, durability, strength, weight, and shrinkage. These aggregates, whether natural, manufactured, or recycled, play a vital role in shaping the quality of concrete.
Aggregates are designated by size, denoted as d/D, following specific sieve selections outlined in Table 1. Compliance requires D/d to be no less than 1.4. A combination of sizes from different sets is strictly prohibited, as detailed in Table 1.
Table 1: Sieve Sizes for Specifying Aggregate Sizes
Sieve Sizes |
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Sizes for Specifying Aggregates |
Grading of aggregates, both coarse and fine, adheres to EN 933-1 standards. Coarse aggregates follow specific requirements based on size designation (d/D), detailed in Table 2. Grading limits, tolerance, and additional requirements are outlined in Tables 2 and 3.
Table 2: Grading Requirement for Coarse Aggregate
Grading Requirement for Coarse Aggregate |
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Grading Requirement for Coarse Aggregate |
Table 3: Overall Limit and Tolerances for Coarse Aggregate Grading
Overall Limit and Tolerances for Coarse Aggregate Grading |
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Limits and Tolerances for Coarse Aggregate Grading |
Fine aggregates adhere to general grading requirements (Table 2), with additional specifications outlined in Table 4 for control of variability.
Table 4: Tolerance on Producer’s Declared Typical Grading for Fine Aggregates
Tolerance on Producer’s Declared Typical Grading for Fine Aggregates |
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Tolerance for Fine Aggregates |
Different concrete applications necessitate specific aggregate gradings. Natural graded 0/8 mm aggregate, all-in aggregate, filler aggregate, and special use aggregates have their unique requirements specified in Tables 5, 6, 7, and specific sieve series (R 20) outlined for special use aggregates.
Table 5: Tolerance on Producer’s Declared Typical Grading for 0/8 mm Aggregate
Tolerance for 0/8 mm Aggregate |
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Tolerance for 0/8 mm Aggregate |
Table 6: Grading Requirement for All-in Aggregates
Grading Requirement for All-in Aggregates |
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Grading Requirement for All-in Aggregates |
Table 7: Grading Requirement for Filler Aggregate
Grading Requirement for Filler Aggregate |
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Grading Requirement for Filler Aggregate |
Shape, determined by the flakiness and shape index, as well as shell content and fines, are crucial factors. Relevant categories for maximum values are specified in Tables 8, 9, 10, and 11.
Table 8: Categories for Maximum Values of Flakiness Index
Categories for Maximum Values of Flakiness Index |
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Maximum Values of Flakiness Index |
Table 9: Categories for Maximum Values of Shape Index
Categories for Maximum Values of Shape Index |
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Maximum Values of Shape Index |
Table 10: Category for Maximum Value of Shell Content of Coarse Aggregate
Category for Maximum Value of Shell Content of Coarse Aggregate |
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Maximum Value of Shell Content of Coarse Aggregate |
Table 11: Categories for Maximum Values of Fines Content
Categories for Maximum Values of Fines Content |
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Maximum Values of Fines Content |
The assessment of fines, including filler aggregate, aligns with Annex D of EN 12620, ensuring a comprehensive understanding of their impact.
In conclusion, the meticulous adherence to geometrical requirements, as per European Standards, ensures the optimal performance of aggregates in concrete, contributing to the overall strength and durability of the constructed structures.