SOUTH AFRICAN NATIONAL STANDARD

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1 ISBN SOUTH AFRICAN NATIONAL STANDARD Particle and relative densities of aggregates WARNING This document references other documents normatively. Published by SABS Standards Division 1 Dr Lategan Road Groenkloof Private Bag X191 Pretoria 0001 Tel: Fax: SABS

2 Table of changes Change No. Date Scope Amdt Amended to change the designation of SABS standards to SANS standards and to update referenced standards. Amdt Amended to update referenced standards. Foreword This South African standard was approved by National Committee SABS/TC 081/SC 01, Construction materials, products and test methods Cement, lime and concrete, in accordance with procedures of the SABS Standards Division, in compliance with annex 3 of the WTO/TBT agreement. This document was published in August This document supersedes SANS 5844:2006 (edition 2.1). A vertical line in the margin shows where the text has been technically modified by amendment No. 2.

3 Particle and relative densities of aggregates 1 Scope and field of application This standard specifies the following two methods for determining the particle and relative densities of aggregates: a) the volumetric (pycnometer) method for fine and coarse aggregate; and b) the hydrostatic balance method for coarse aggregate. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this standard. All standards are subject to revision and, since any reference to a standard is deemed to be a reference to the latest edition of that standard, parties to agreements based on this standard are encouraged to take steps to ensure the use of the most recent editions of the standards indicated below. Information on currently valid national and international standards can be obtained from the SABS Standards Division. SANS 197, Preparation of test samples for aggregates. SANS /ISO , Test sieves Technical requirements and testing Part 1: Test sieves of metal wire cloth. Amdt 1 SANS /ISO , Test sieves Technical requirements and testing Part 2: Test sieves of perforated metal plate. Amdt 1 SANS 5843 (SABS SM 843), Water absorption of aggregates. Amdt 2 SANS 3001-AG20, Civil engineering test methods Part AG20: Determination of the bulk density, apparent density and water absorption of aggregate particles retained on the 5 mm sieve for road construction materials. Amdt 2 SANS 3001-AG21, Civil engineering test methods Part AG21: Determination of the bulk density, apparent density and water absorption of aggregate particles passing the 5 mm sieve for road construction materials. Amdt 2 1

4 3 Definitions For the purposes of this standard, the following definitions apply: 3.1 apparent relative density the ratio of the mass of a sample of aggregate particles (excluding water-permeable pores but including water-impermeable pores normal to the particles) to the mass of an equal volume of water at the temperature specified 3.2 particle density the ratio of the mass of a sample of aggregate particles to the volume it occupies (including both water-permeable and water-impermeable pores normal to the particles) at the temperature specified 3.3 water-permeable (or open) pores voids that are water-filled when the particles are in a saturated and surface-dry condition 4 Apparatus 4.1 Pycnometer, that consists of clean, dry, rigid volumetric vessel or flask (with stopper or cover) of non-absorbent material into which the aggregate can be readily inserted, of volume at least twice that of the test aggregate and in which the volume content can be reproduced to within ± 0,1 %. NOTE A wide-mouthed glass vessel such as a 1 kg fruit-preserving jar (with a flat ground lip and a plane ground disc of plate glass to cover it, providing a watertight fit) or any suitable sized glass jar may be used. 4.2 Balance, of adequate capacity and accurate to within 0,1 % of the mass of the material to be determined, and such that the basket (see 4.3) that contains the test specimen can be suspended from the balance and the mass determined in water. 4.3 Basket, of mesh with apertures of size 1 mm to 3 mm, or a perforated container (perforations of diameter of 1 mm to 3 mm) of convenient size, preferably of polished chromium-plated steel or stainless steel, with wire hangers (of thickness not exceeding 1 mm) to allow suspension from the balance. 4.4 Watertight tank, in which the basket (see 4.3) can be freely suspended. 4.5 Test sieve, of aperture size µm and that complies with the requirements of SANS and SANS Amdt 1 5 Procedure NOTES 1 Two volumetric (pycnometer) methods are described: a) the particle and relative densities of the fine and coarse aggregate; and b) the apparent relative density of fine and crushed coarse aggregate. 2 The particle density is determined on a saturated surface-dried basis or on an oven-dried basis (or on both). 2

5 3 All water used should be free from any impurity (for example dissolved air) that would significantly affect its density. In cases of doubt, distilled, demineralized or tap water that has been freshly boiled and cooled to a temperature of between 20 C and 25 C, should be used. 4 All masses are accurately determined to at least 0,1 %. 5.1 Pycnometer method Particle and relative densities of aggregates Preparation of test specimen Prepare a test specimen of approximately 500 g in the saturated surface-dry condition, as described in SANS 5843 (4.1.1 to for fine aggregate, and to for coarse aggregate) SANS 3001-AG20 and SANS 3001-AG21. Amdt Procedure Place the prepared test specimen in the dry and tared pycnometer, insert the stopper (see 4.1) and determine the mass of the specimen (mass m a ) Introduce enough water into the pycnometer to cover the specimen (in such a manner that it washes down any particles adhering to the sides). Gently shake, roll or tap the pycnometer, with contents, until all entrapped air has escaped. NOTE Entrapped air can be removed by means of low vacuum (air pressure not exceeding 13 kpa) Fill the pycnometer with water to its calibrated capacity. Note the temperature T of the water, and insert the stopper or cover the pycnometer with the plate glass, ensuring that no air is entrapped. Thoroughly dry and clean the outside of the pycnometer and determine the mass of the pycnometer, with contents (mass m c ) Empty the contents of the pycnometer into a suitable container, ensuring that all the aggregate is transferred. Wash the pycnometer thoroughly and fill it to its calibrated capacity with water at a temperature of T C ± 1 C. Thoroughly dry the outside of the pycnometer and determine the mass of the pycnometer when it is filled with water (mass m d ) If the relative density or the oven-dry particle density is required, carefully decant the water from the aggregate in the container, taking care not to loose any solids, and dry to constant mass in an oven at 100 C to 110 C. Cool in a desiccator and determine the mass of the ovendried specimen (mass m b ) Apparent relative density of fine and crushed coarse aggregate NOTE For this method, a pycnometer that consists of a volumetric flask (with stopper) of capacity approximately 1 L and of known mass is deemed to be the most suitable Preparation of test specimen Fine aggregate From the test sample (see SANS 197), take a suitable quantity of aggregate and sieve it through a sieve of nominal aperture size µm. Crush any material coarser than µm until it all passes this sieve. Dry the test specimen to constant mass at a temperature of 100 C to 110 C. 3