AS 1141.34:2018 pdf free download – Methods for sampling and testing aggregates
1  Scope
This Standard sets out a method for an approximate determination of the presence of organic materials,other than sugar, present in fine aggregate.
2  Principle
The test relies on the reaction of humus material with a sodium hydroxide solution to produce a dark colour in the liquid the intensity of which is approximately proportionate with the mass content of humus in the fine aggregate. Based on 1917 research, fine aggregate with humus contents that have a resultant solution colour lighter than, or equal to, the Standard colour are expected to have no detrimental effects when used in concrete or mortar products. A darker coloured solution may be the result of humus content and/or reactions from other contaminents and may require further investigation to determine the extent of possible effects to concrete or mortar properties.
3  Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document.
AS 1141.2, Methods for sampling and testing aggregates, Part 1: Definitions
AS 1141.2, Methods for sampling and testing aggregates, Method 2: Basic testing equipment
AS 1141.3.1, Methods for sampling and testing aggregates, Method 3.1: Sampling Aggregates
4  Definitions
For the purpose of this Standard the definitions in AS 1141.1 apply.
5  Safety precautions
Procedures using strong alkalis, including the preparation of dilute solutions of these chemicals, should be carried out with care.
WARNING — STRONG ALKALIS ARE HAZARDOUS AND CAN RESULT IN OFTEN IRREVERSIBLE DAMAGE TO THE SKIN OR EYES. INGESTION OF THE CHEMICAL, INHALATION OF THE FUMES, OR SKIN CONTACT CONSTITUTES A SERIOUS HEALTH HAZARD.
Appropriate documentation should be consulted as to safety precautions.
6  Apparatus
The following apparatus, conforming to the relevant provisions of AS 1141.2, is required:
(a) Stoppered rectangular clear glass bottles — of approximately 350 mL or greater capacity.
NOTE  Suitable bottles were known as graduated prescription bottles. Other containers may be used provided the light path for the comparison test is the same for the test solution and the standard solution [see Clause 10(c)]. European Standard EN 1744‑1:2009 specifies a clear, cylindrical stoppered glass bottle approximately 450 mL with an external diameter of 70 mm.
8  Test portion
By coning and quartering or using sample dividers, take a test portion of approximately 100 g from a laboratory sample obtained in accordance with the procedures of AS 1141.3.1. The test portion shall be used in the condition in which it was received.
9  Solutions required
The following solutions are required:
(a) Sodium hydroxide solution — A solution of 30 g of sodium hydroxide in 970 mL of distilled or deionized water.
(b) Reference colour solution — Two grams of tannic acid shall be dissolved in 10 mL of ethanol (ethyl alcohol), and the solution diluted to 100 mL with distilled water, then 2.5 mL of the resultant solution shall be added to 97.5 mL of the 3 % sodium hydroxide solution. The mixture shall be shaken vigorously and then allowed to stand in subdued light for 1 h before use. The reference colour solution shall be used within 2 h of its preparation [see Clause 10(c)].