AS 1141.26 pdf download

AS 1141.26 pdf download.Methods for sampling and testing aggregates
1  Scope
This Method sets out the method for determining the content of secondary or deuteric minerals of rock spalls, bore cores and aggregates of igneous rocks using a petrological microscope. This Method is not applicable to rocks that have developed a clearly identifiable metamorphic texture or mineral assemblage, or to sedimentary rocks. NOTE 1  As secondary minerals are not necessarily deleterious, the method should not be used alone to provide a measure of the quality of the source rock or product. NOTE 2  The method is suitable for continuing routine assessment of known rock sources as confirmation that the extent and type of secondary minerals have not changed significantly and do not exceed accepted specification limits. This Method should not be used — (a) to investigate new rock sources or for previously unknown rock types in known sources; (b) to investigate other properties of rocks which may limit engineering applications (e.g. potential alkali aggregate reactivity or respirable silica content); (c) to investigate failures; or (d) when the genesis of the rock is unclear (e.g. is a deep seated rock type considered a melt or a high grade metamorphic). In all these cases a more detailed petrological method is recommended. NOTE 3  Throughout most of Australia the procedure of ASTM C-295 is usually employed.
4  Terms and definitions
For the purpose of this Standard, the definitions in AS 1141.1 and those below apply. 4.1 may indicates the existence of an option 4.2 primary minerals minerals that existed in the rock at the time of its formation Primary minerals may be further divided into the following: (a) Essential minerals, whose presence is implied in the definition or classification of the rock. (b) Accessory minerals, whose presence or absence does not affect the definition or classification of the rock. Note 1 to entry: Volcanic glass is classified as a primary mineral for the purpose of this Standard. 4.3 secondary minerals minerals that have resulted from the alteration or reconstruction of the primary minerals by weathering or other agents, or that have been introduced and deposited within the rock mass by groundwater movements or other agents (e.g. infilled microcrack) Note 1 to entry: For the purposes of this Standard, deuteric minerals are also classified as secondary minerals. 4.4 shall indicates that a statement is mandatory 4.5 should indicates a recommendation
5  Apparatus
5.1  General Apparatus for facilities reporting on, but not preparing, thin sections are set out in Clauses 5.2 and 5.3. This clause lists both essential apparatus and optional apparatus; the latter being useful for more detailed examinations but may not be required for this method. The apparatus to be used by facilities preparing thin sections as part of this Method is given in Clause 5.4. 5.2  Essential apparatus For examination of thin sections, the following apparatus are required: (a) Petrological (polarizing) microscope, fitted with low-, medium- and high-power objectives and with eyepieces of various powers (typically 6X to 150X). (b) Microscope accessories, including a mechanical stage unit, first order red and quarter-wave compensators and a quartz wedge. (c) Automated point counter, with a grid of at least 300 points but preferably 600 points.5.3  Optional apparatus The following equipment may be of use in some applications such as when clients request photomicrographs as part of the report or when very fine-grained rocks require the use of a high- powered lens with immersion oil. (a) Microscope accessories, filters and light source for fluorescence observations carried out in either transmitted or reflected light. (b) Microscope accessories, oil immersion lenses. (c) Magnet. (d) Needle holder and points. (e) Forceps. (f) Lens paper. (g) Immersion media. (h) Photomicrographic camera with micron scale. 5.4  Apparatus for preparation of thin sections The following apparatus is required for the preparation of thin sections: (a) Rock saw with diamond impregnated blades of different sizes. (b) Vertical grinding wheel. (c) Horizontal grinding wheel. (d) Polishing wheel. (e) Grinding abrasives generally in descending grain sizes from 150 μm to 5 μm. (f) Glass microscope slides. (g) Mounting media usually epoxy resins. (h) Canada balsam. (i) Xylene. (j) Cover slips. (k) Laboratory oven, operating between 40 °C and 45 °C.