🏗️ Particle density and water absorption of aggregate (the wire basket and pyknometer methods)
In short
The reference methods: the wire basket (particles > 31. 5 mm) and the pyknometer (31. The test is performed according to PN-EN 1097-6:2022-07; Division into methods: Wire basket: particles retained on the 31.5 mm sieve; pyknometer: 31.5/4 mm and 4/0.063 mm. The procedure comprises 8 steps (about 1 days in total); it is used for: Type testing of aggregates for concrete and asphalt mixtures (the particle density for the design of the composition), Assessment of the water absorption as an indirect measure of the freeze-thaw resistance of an aggregate (the WWiORB technical specifications of GDDKiA: the category WA24 1), Lightweight aggregates: the density and water absorption of coarse (Annex C) and fine ones (Annex D).
At a glance
- Standard: PN-EN 1097-6:2022-07
- Category: Construction
- Procedure steps: 8
- Total time of stages: 1 days
- Division into methods: Wire basket: particles retained on the 31.5 mm sieve; pyknometer: 31.5/4 mm and 4/0.063 mm
- Soaking: 24 h (clauses 7–9); to constant mass in Annex B
- Pyknometer: 1000–5000 ml (31.5/4 mm) or 500–2000 ml (4/0.063 mm), a constant volume to 0.5 ml; the test portion about half the volume
Overview
The standard PN-EN 1097-6 specifies the reference methods, used in type testing and in cases of dispute, for determining the particle density and water absorption of normal-weight and lightweight aggregates; other methods may be used for other purposes (for example factory production control) once their relationship with the reference method has been established. For normal-weight aggregates the reference methods are: the wire basket method for particles retained on a 31.5 mm sieve (clause 7; railway ballast according to Annex B), the pyknometer method for 31.5/4 mm particles (clause 8) and the pyknometer method for 4/0.063 mm particles (clause 9). In clauses 7–9 three densities are determined — the oven-dried particle density (ρrd), the saturated and surface-dried particle density (ρssd) and the apparent particle density (ρa) — and the water absorption after 24 h of soaking.
The water absorption is the mass of the water absorbed expressed as a percentage of the mass of the oven-dried sample. The 2022 edition replaced PN-EN 1097-6:2013: among other things the minimum volume of the pyknometer in A.4 was increased from 250 ml to 500 ml, an illustration of the assessment of the surface-dry condition by the cone method was added in clause 9, the removal of air from the pyknometer by vacuum was allowed, a new Annex D was added for fine lightweight aggregates (a Büchner funnel, a vacuum of 50–100 mbar for ≥ 5 min) and an Annex F for particles below 4 mm. Annexes A and H describe rapid methods for the pre-dried particle density (ρp), and Annex E a rapid method for coarse lightweight aggregates.
The water absorption is an indirect measure of the freeze-thaw resistance of an aggregate: for concrete pavements the WWiORB technical specifications of GDDKiA require a water absorption according to clause 7, 8 or 9 of the category WA24 1 and take an aggregate with a water absorption no greater than that category to be freeze-thaw resistant. The particle density, in turn, is indispensable for the volumetric calculations of concrete and asphalt mixtures.
Method principle
The particle density is calculated as the mass divided by the volume. The mass is determined by weighing the sample in the saturated and surface-dried condition and in the oven-dried condition; the volume from the mass of the water displaced: from the loss of mass in the wire basket method or from the weighings in the pyknometer method. The sample is not to be heated artificially before the test (an effect on the water absorption); if that has been done, it has to be stated in the test report. An aggregate consisting of several fractions may require separation before the test portion is prepared, and the proportion of the fractions is stated in the test report. Constant mass: successive weighings at intervals of ≥ 1 h differing by ≤ 0.1 %.
Applications
- Type testing of aggregates for concrete and asphalt mixtures (the particle density for the design of the composition)
- Assessment of the water absorption as an indirect measure of the freeze-thaw resistance of an aggregate (the WWiORB technical specifications of GDDKiA: the category WA24 1)
- Lightweight aggregates: the density and water absorption of coarse (Annex C) and fine ones (Annex D)
- Railway ballast — the particle density saturated to constant mass (Annex B)
- Rapid determinations of the pre-dried particle density in factory production control (Annexes A, E, H)
Key parameters
| Parameter | Value |
|---|---|
| Division into methods | Wire basket: particles retained on the 31.5 mm sieve; pyknometer: 31.5/4 mm and 4/0.063 mm |
| Soaking | 24 h (clauses 7–9); to constant mass in Annex B |
| Pyknometer | 1000–5000 ml (31.5/4 mm) or 500–2000 ml (4/0.063 mm), a constant volume to 0.5 ml; the test portion about half the volume |
| Temperatures | Oven (110 ± 5) °C; water bath (22 ± 3) °C; a thermometer accurate to 0.1 °C |
| Cone mould and tamper (particles < 4 mm) | A cone of (40 ± 3)/(90 ± 3) mm × (75 ± 3) mm, sheet of ≥ 0.8 mm; a tamper of (340 ± 15) g, a face of Ø (25 ± 3) mm |
| Result | ρrd, ρssd, ρa and the water absorption WA24 in % of the dry mass |
Standard
- Standard number
- PN-EN 1097-6:2022-07
- Title (PL)
- Badania mechanicznych i fizycznych właściwości kruszyw — Część 6: Oznaczanie gęstości ziarn i nasiąkliwości
- Title (EN)
- Tests for mechanical and physical properties of aggregates — Part 6: Determination of particle density and water absorption
Step-by-step procedure
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Choice of the method
Sieve the sample on 63; 31.5; 4 and 0.063 mm sieves and assign the fractions to the methods: wire basket (> 31.5 mm; also permitted for 31.5/4 mm), pyknometer 31.5/4 mm (also permitted for 4/2 mm), pyknometer 4/0.063 mm. State the proportion of the fractions in the test report.
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Preparation of the test portion
Do not heat the sample artificially before the test; wash and reduce it in accordance with PN-EN 932-2 and PN-EN 932-5 to the mass required for the method concerned.
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Soaking
Soak the test portion in water in the bath at (22 ± 3) °C for 24 h (clauses 7–9).
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Weighing in water (basket) or in the pyknometer
The basket method: weigh the basket with the test portion fully immersed in the water tank. The pyknometer method: weigh the pyknometer with the test portion and water after the air has been removed (in A.4 vacuum is permitted), with the temperature of the water controlled.
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The saturated and surface-dried condition
Dry the surface of the particles with absorbent cloths (coarse particles) or with warm air with the cone check (4/0.063 mm particles: the cone slumps when the mould is lifted) and weigh the test portion.
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Drying
Dry the test portion at (110 ± 5) °C to constant mass (successive weighings at intervals of ≥ 1 h differing by ≤ 0.1 %), cool it and weigh it.
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Calculations
From the masses in the oven-dried condition, in the saturated and surface-dried condition and in water, calculate ρrd, ρssd and ρa and the water absorption as the percentage of the water absorbed relative to the dry mass; the density of water at the temperature of the test from Annex G.
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Test report
State the method (the clause or annex), the proportion of the fractions, any artificial heating of the sample, the results for the density and the water absorption and the optional data of 10.2.
Required equipment and apparatus
| Equipment | Example | Indicative price |
|---|---|---|
| Ventilated oven | (110 ± 5) °C | — |
| Balance | Accuracy 0.1 % of the mass of the test portion, able to weigh the basket with the test portion immersed in water | — |
| Wire basket and water tank | A corrosion-resistant basket or perforated container suspended from the balance; a tank of water at (22 ± 3) °C with a clearance of ≥ 50 mm around the basket | — |
| Pyknometer | A glass flask with a funnel, 1000–5000 ml or 500–2000 ml, a constant volume to 0.5 ml | — |
| Cone mould and tamper | For assessing the surface-dry condition of 4/0.063 mm particles; a tray of ≥ 0.1 m² with a rim of ≥ 50 mm, a hair dryer (warm air) | — |
| Sieves, water bath, thermometer, trays, absorbent cloths, washing equipment, stopwatch | Sieves of 0.063; 4; 31.5 and 63 mm according to PN-EN 933-2; a bath at (22 ± 3) °C; a thermometer of 0.1 °C | — |
Reagents, media and consumables
| Reagent | CAS | Details |
|---|---|---|
| Water | — | Free of impurities affecting the density (dissolved air, dissolved substances); distilled water boiled and cooled or demineralised water is recommended, fresh tap water is permitted; dissolved air may be removed by vacuum |
Health and safety (OHS)
- Glass pyknometers of 1–5 l with water and aggregate are heavy and brittle — carry them with both hands and do not put hot ones on a cold bench top
- The oven at 110 °C — heat-resistant gloves; cool the test portions before weighing
- Work with vacuum when removing air — use vessels intended for vacuum
Frequently asked questions
Which standard describes this test?
The test is performed according to PN-EN 1097-6:2022-07 — “Tests for mechanical and physical properties of aggregates — Part 6: Determination of particle density and water absorption”.
How does this method work?
The particle density is calculated as the mass divided by the volume. The mass is determined by weighing the sample in the saturated and surface-dried condition and in the oven-dried condition; the volume from the mass of the water displaced: from the loss of mass in the wire basket method or from the weighings in the pyknometer method.
What is the measuring range and accuracy?
Division into methods: Wire basket: particles retained on the 31.5 mm sieve; pyknometer: 31.5/4 mm and 4/0.063 mm; Soaking: 24 h (clauses 7–9); to constant mass in Annex B; Pyknometer: 1000–5000 ml (31.5/4 mm) or 500–2000 ml (4/0.063 mm), a constant volume to 0.5 ml; the test portion about half the volume; Temperatures: Oven (110 ± 5) °C; water bath (22 ± 3) °C; a thermometer accurate to 0.1 °C.
How long does the test take?
The times given for the individual stages add up to approximately 1 days. The procedure comprises 8 steps.
What equipment is required?
Ventilated oven, Balance, Wire basket and water tank, Pyknometer, Cone mould and tamper, Sieves, water bath, thermometer, trays, absorbent cloths, washing equipment, stopwatch.
Where is this test used?
Type testing of aggregates for concrete and asphalt mixtures (the particle density for the design of the composition); Assessment of the water absorption as an indirect measure of the freeze-thaw resistance of an aggregate (the WWiORB technical specifications of GDDKiA: the category WA24 1); Lightweight aggregates: the density and water absorption of coarse (Annex C) and fine ones (Annex D); Railway ballast — the particle density saturated to constant mass (Annex B); Rapid determinations of the pre-dried particle density in factory production control (Annexes A, E, H).
What safety precautions apply?
Glass pyknometers of 1–5 l with water and aggregate are heavy and brittle — carry them with both hands and do not put hot ones on a cold bench top; The oven at 110 °C — heat-resistant gloves; cool the test portions before weighing; Work with vacuum when removing air — use vessels intended for vacuum.
Which laboratory can perform this test?
The test is performed by laboratories accredited to ISO/IEC 17025. On LabCoda you can find them by the standard number PN-EN 1097-6.