đź•‘ Reading time: 1 minute
The aggregates used in the production of concrete are inert granular materials such as gravel, crushed stone, sand, slag, recycled concrete, and geosynthetic aggregates. The aggregates may be natural, manufactured, or recycled.
This article is in continuation of the article: Geometrical Requirement of Aggregates as per European Standards [PDF].
In this article, we discuss the physical requirement of the aggregates such as resistance to fragmentation, wear, polishing, abrasion, particle density, bulk density, and durability used in the production of concrete as per the European Standards (EN – 12620).
Contents:
1. Resistance to Fragmentation of Coarse Aggregate
The resistance to fragmentation shall be determined with the Los Angeles test method as a reference in terms of the Los Angeles coefficient, as specified in EN 1097-2:1998, clause 5.
The obtained Los Angeles coefficient shall be declared in accordance with the relevant category specified in Table 12, according to the particular application or end-use.
Table 12 - Categories for maximum values of Los Angeles coefficients
Where required, the impact value determined in accordance with EN 1097-2:1998, clause 6, shall be declared in accordance with the relevant category specified in Table 13 according to the particular application or end-use.
Table 13: Categories for maximum values of resistance to impact
2. Resistance to Wear of Coarse Aggregate
The resistance to wear of coarse aggregate shall be determined in accordance with EN 1097-1. The micro-deval coefficient shall be declared in accordance with the relevant categories specified in Table 14, according to the particular application or end-use.
Table 14: Categories of maximum values of resistance to wear
3. Resistance to Polishing
The resistance to polishing of coarse aggregate to be used for surface courses (polished stone value-PSV) shall be determined in accordance with EN 1097-8. The resistance to polishing shall be declared in accordance with the relevant category specified in Table 15.
Table 15 - Categories for minimum values of resistance to polishing
4. Resistance to Surface Abrasion
The resistance to surface abrasion (aggregate abrasion value - AAV), shall be determined in accordance with EN 1097-8:1999, annex A. The resistance to surface abrasion shall be declared in accordance with the relevant category specified in Table 16.
Table 16: Categories for maximum values of resistance to surface abrasion
5. Resistance to Abrasion from Studded Tires
The resistance to abrasion from studded tires (Nordic abrasion value- An), shall be determined in accordance with EN 1097-9. Resistance to abrasion from studded tires shall be declared in accordance with the relevant category specified in Table 17.
Table 17 - Categories for maximum values of resistance to abrasion from studded tires
6. Particle Density and Water Absorption
The particle density and water absorption shall be determined in accordance with EN 1097-6, and the results declared on request stating the means of determination and the calculations used.
7. Bulk Density
When required, the bulk density shall be determined in accordance with EN 1097-3, and the results declared on request.
8. Durability
8.1 Freeze and Thaw Resistance of Coarse Aggregate
The aggregates used in the environment subjected to freezing and thawing shall be tested in accordance with EN 1367-1 or EN 1367-2, respectively, in accordance with the relevant category specified in Table 18 or Table 19.
Table 18: Categories of maximum values of freeze-thaw resistance.
Table 19: Categories of maximum Magnesium sulfate soundness
8.2 Volume Stability - Drying Shrinkage
In case where disruptive shrinkage cracking of concrete occurs due to the properties of the aggregate, the drying shrinkage associated with aggregates to be used in structural concrete shall, when required, not exceed 0,075 % when tested in accordance with EN 1367-4 and the results declared.
8.3 Alkali-Silica Reactivity
When required, the alkali-silica reactivity of aggregates shall be assessed in accordance with the provisions valid in the place of use, and the results declared.
The properties of concrete such as workability, durability, strength, weight, and, shrinkage are governed by the properties (composition, shape, and size) of aggregate used in the concrete.
Commonly, aggregate passing the sieve of 20mm and retaining the sieve of 12.5mm is preferred for the production of concrete.
Read More
1. Geometrical Requirement of Aggregates as per European Standards
2. Aggregates for Concrete as per American Standards – ASTM
