AS 1141.19 pdf download
AS 1141.19 pdf download.Methods for sampling and testing aggregates
1 Scope
This Standard sets out the method for the determination of the fine particle size distribution in road materials. The procedure for the determination of coarse particle size distribution and particle size distribution for fillers for asphalt is described in AS 1141.11.1. WARNING — THE STANDARD PROCEDURE FOR THE DETERMINATION OF THE FINE PARTICLE SIZE DISTRIBUTION IN ROADBASE ACCORDING TO THIS METHOD, INVOLVES THE REPEATED BOILING OF THE TEST PORTION IN A DILUTE SOLUTION OF AMMONIA WHICH IS USED AS A DISPERSING AGENT. THE PROCEDURE SHOULD BE CONDUCTED UNDER A FUME HOOD WHICH WILL REMOVE AMMONIA FUMES AND DISCHARGE THE FUMES TO EXTERIOR ATMOSPHERE. FAILURE TO EXTRACT FUMES, ALLOWING THEM TO ENTER THE WORKING SPACE, WILL CAUSE DISCOMFORT TO STAFF IN THE FORM OF EYE AND NASAL IRRITATION. STAFF WITH BREATHING DIFFICULTIES MAY BE AFFECTED SERIOUSLY. IF EXTRACTION FACILITIES ARE NOT AVAILABLE, THE USE OF AMMONIA SHOULD BE AVOIDED IN FAVOUR OF THE ALTERNATE DISPERSING AGENTS (SEE CLAUSE 7(I) NOTE 2).
2 Principle
The particle size distribution is determined by dry sieving in the case of materials coarser than 2.36 mm and by decantation in the case of materials finer than 2.36 mm. In the latter case the proportions determined are those passing 425 μm and 75 μm sieves and that are less than 13.5 μm diameter. The determination of the 13.5 μm particle size is based on the application of Stokes Law. The particle sizes determined enable the assessment of roadbase products based on ratios derived from Wilhelmi’s formula for maximum density grading.
5 Apparatus
The following apparatus, conforming to the relevant provisions of AS 1141.2, is required: (a) Balances — of adequate capacity with a limit of performance not exceeding ± 5 g for coarse fraction and ± 0.5 g for the fine fraction of the aggregate. (b) Beakers — Pyrex squat form, 1 L capacity, with lip and pouring spout. Graduation marks to be made on the side of each beaker to indicate levels 30 mm and 110 mm above the base of the beaker. Alternatively, metal beakers of a similar shape and marked on the inside may be used. (c) Bench — a decantation bench. (d) Cans — metal boiling cans with a capacity of at least 1 L. Beakers may be used provided that a fire resistant mat or a sandbath is used. (e) Desiccator — preferably cabinet type. (f) Dishes — metal dishes approximately 100 mm, 225 mm and 350 mm in diameter. (g) Dispensing device — for dispersing agent. (h) Heating device — with rapidly adjustable temperature control. (i) Mixing apparatus — trowel and spatula; quartering apparatus, e.g. metal plates 400 mm × 125 mm and 20 mm × 125 mm. (j) Mixing and quartering tray — metal. (k) Mortar — porcelain, approximately 180 mm diameter with porcelain and rubber pestles. (l) Ovens — of the following types: (i) Thermostatically controlled, with good air circulation capable of maintaining a temperature not exceeding 50 °C. (ii) Thermostatically controlled, with good air circulation capable of maintaining a temperature within the range of 105 °C to 110 °C. (m) Sample dividers (riffle boxes) (optional) — of appropriate size openings. (n) Sieves — 53.0 mm, 37.5 mm, 26.5 mm, 19.0 mm, and 9.50 mm (as required), 4.75 mm (perforated plate), 2.36 mm, 425 μm and 75 μm (wire cloth). (o) Sieve brushes. (p) Sieve shaking machine (optional) — bench type. (q) Stirring rods — glass, rubber-tipped. (r) Thermometer — covering the range of 0 °C to 100 °C, graduated to 1 °C or less, with an uncertainty not exceeding 0.5 °C. (s) Timing device — indicating in seconds and minutes.
6 Preparation of samples
The sample shall be prepared as follows: (a) Obtain a sample in accordance with AS 1141.3.1.(b) Allow the sample to dry sufficiently to enable it to be crumbled. If necessary, dry the sample in an oven at a temperature not exceeding 50 °C. (c) Break up any aggregations of particles without crushing any discrete particles. All aggregations are to be broken down so that if the sample were screened on a 2.36 mm sieve, only discrete, uncrushed particles would be retained. A rubber pestle shall be used so that sound pieces of mineral matter are not broken down. Adhering material shall be brushed from the coarse pieces. When in doubt as to whether lumps are to be broken, place some in water and boil. If slaking occurs, the material should be broken further with the rubber pestle. (d) Reduce the sample as necessary, by quartering or riffling, to provide an amount to yield not less than 150 g of material passing a 2.36 mm sieve. (e) Screen the sample on a 4.75 mm sieve. Sieves shall not be overloaded. To facilitate this operation place larger sieves over the 4.75 mm sieve as appropriate. (f) Dry the material passing the 4.75 mm sieve to constant mass at a temperature within the range 105 °C to 110 °C. The material shall not be left in the oven for longer than 18 h. Cool in a desiccator. NOTE The material retained on the 4.75 mm sieves and those above that size may be retained, if required, for testing using AS 1141.11.1.
