As 2758.1-1998 Concrete Aggregates

AS 2758.1—1998

Australian Standard Aggregates and rock for engineering purposes

Accessed by CONNELL WAGNER on 09 Mar 2004

Part 1: Concrete aggregates

This Australian Standard was prepared by Committee CE/12, Aggregates and Rock for Engineering Purposes. It was approved on behalf of the Council of Standards Australia on 21 November 1997 and published on 5 February 1998.

The following interests are represented on Committee CE/12: ARRB Transport Research Australasian Railway Association Australasian Slag Association Australian Asphalt Pavement Association Australian Geomechanics Society Australian Premixed Concrete Association Australian Stone Industry Association AUSTROADS Bureau of Steel Manufacturers of Australia Cement and Concrete Association of Australia CSIRO — Division of Building, Construction and Engineering Crushed Stone Association of Australia Crushed Stone Association (Qld) Institute of Municipal Engineering Australia, New South Wales Division Monash University National Association of Testing Authorities, Australia National Public Works Council National Ready Mixed Concrete Association of New South Wales


Quarry Masters Association of New South Wales

Review of Australian Standards. To keep abreast of progress in industry, Australi an Standards are subject to periodic review and are kept up to date by the issue of amendments or new editions as necessary. It is important therefore that Standards users ensure that they are in possession of the latest editi on, and any amendments thereto. Full details of all Australi an Standards and related publicati ons will be found in the Standards Australia Catalogue of Publi cations; this information is supplemented each month by the magazine ‘The Australian Standard’, which subscribing members receive, and which gives detail s of new publications, new editions and amendments, and of withdrawn Standards. Suggestions for improvements to Australian Standards, addressed to the head office of Standards Australia, are welcomed. Notification of any inaccuracy or ambiguity found in an Australian Standard should be made wit hout delay in order that the matter may be investigated and appropriate action taken.

This Standard was issued in draft form for comment as DR 96269.

AS 2758.1—1998

Australian Standard Aggregates and rock for engineering purposes Part 1: Concrete aggregates


Originated as part of AS A24— 1934. Previous edition AS 2758.1— 1985. Second edition 1998.

PUBLISHED BY STANDARDS AUSTRALIA (STANDARDS ASSOCIATION OF AUSTRALIA) 1 THE CRESCENT, HOMEBUSH, NSW 2140 ISBN 0 7337 1730 6

AS 2758.1 — 1998

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PREFACE This Standard was prepared by the Standards Australia Committee CE/12, Aggregates and Rock for Engineering Purposes, to supersede AS 2758.1 — 1985. This Standard is part of a series which covers specification of aggregates and rock. The other Parts are as follows: Part 2: Aggregate for sprayed bituminous surfacing Part 5: Asphalt aggregates Part 7: Railway ballast This Standard is called up by AS 3600, Concrete structures. In this Standard, extensive reference is made to AS 1141, Methods for sampling and testing aggregates , which is designed to include all aggregate tests, not only those for concrete. The following clauses cover properties that are required to be known for a mix design and the works specification should provide choices or limits for them: (a)

Clause 7.1, for particle density.

(b)

Clause 7.2, for bulk density.

(c)

Clause 7.3, for water absorption.

(d)

Clause 8.1, for particle size distribution.

(e)

Clause 10, for alkali aggregate reactivity.

(f)

Clause 14.3, for soluble salts if above the limits given.

The remaining aggregate properties in this Standard are given limits. Durability of coarse aggregate is related to the use of concrete and its exposure and is not a mix design factor. The works specification should select an exposure classification and a method of assessment (see Clause 9.3). NOTE: Exposure classifications for various uses of concrete can be found in Appendix A. Appendix B gives information on petrological terminology and classification of aggregate sources including particle shape and texture.


When works specifications are being drafted by consultants or engineers based on this Standard, it is intended that only one procedure be nominated for each property being specified. A specification is likely to lead to conflict if more than one procedure is specified for a particular property (see coarse aggregate durability). It is recognized that satisfactory concrete can sometimes be made with aggregates which will not comply with this Standard in all respects, but the use of such aggregates should be authorized only after special testing or consideration of previous experience with the particular aggregates concerned. It is also recognized that concrete for specialized requirements may necessitate more stringent limits for aggregates than those given in this Standard. It should be noted that compliance with the grading requirements given in Tables 1 and 3 will not necessarily ensure the production of workable concrete in all mix proportions. The determination of mix proportions should be related to the actual nature and grading of the aggregates to be used. The terms ‘normative’ and ‘informative’ have been used in this Standard to define the application of the appendix to which they apply. A ‘normative’ appendix is an integral part of a Standard, whereas an ‘informative’ appendix is only for information and guidance.

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AS 2758.1 — 1998

CONTENTS Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . APPLICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REFERENCED DOCUMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DEFINITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SAMPLING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TESTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GENERAL REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DIMENSIONAL REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DURABILITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ALKALI-REACTIVE MATERIALS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WEAK PARTICLES IN COARSE AGGREGATE . . . . . . . . . . . . . . . . . . . . . . LIGHT PARTICLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DRYING SHRINKAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IMPURITIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ADDITIONAL REQUIREMENTS FOR SLAG AGGREGATES . . . . . . . . . . . . ADDITIONAL REQUIREMENTS FOR LIGHTWEIGHT AGGREGATES . . . . .

4 4 4 5 6 6 6 7 10 13 13 13 13 14 14 15


APPENDICES A EXPOSURE CLASSIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 B TERMINOLOGY AND CLASSIFICATION (PETROLOGICAL) . . . . . . . . . . 19

 Copyright

STANDARDS AUSTRALIA

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AS 2758.1 — 1998

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STANDARDS AUSTRALIA Australian Standard Aggregates and rock for engineering purposes Part 1: Concrete aggregates 1 SCOPE This Standard provides a intended for use in the production requirements and alternatives relate to including lightweight aggregates, and AS 1012 and AS 4489.

basis for specifying requirements for aggregates of concrete, including precast products. The quality of rock and the properties of aggregates refer to the relevant test methods in AS 1141,

2 APPLICATION This Standard shall be used in combination with a works specification for contract purposes. While a number of the requirements nominated are basic, the specifier shall make a selection from the options available in this Standard, or from alternative test methods and limits (which may be from Australian Standards or other appropriate Standards) for incorporation into the works specification. The basic requirements for all concrete aggregates are prescribed in Clauses 7 to 14 of this Standard. Additional basic requirements for slag and lightweight aggregates are prescribed in Clauses 15 and 16 respectively. Alternatives are presented for the assessment of durability in Clause 9. However, not more than one of these alternatives shall be specified. The selection of test procedures and test limits where alternatives are provided, and the frequency at which individual tests are required, shall be determined by the individual works specification. The works specification should specify all the tests appropriate to the source rock or the tender samples, or both, but the whole range of tests is not necessarily applied to control acceptance of the product during the performance of a contract.


For contractual purposes it is the works specification which is binding. However, the case may arise where a contract document uses phrases such as ‘material complying with AS 2758.1’ without providing a works specification. In this event the supplier shall attempt to obtain further details from the purchaser. In the continued absence of a works specification, material will be deemed to comply with AS 2758.1 if the supplier operates a quality system that conforms to AS/NZS ISO 9002 and can provide test data from a laboratory accredited to SAA HB 18.25 showing that the material to be supplied — (a)

is of normal weight;

(b)

fulfils the requirements for aggregate to be used in concrete in B1, B2 exposure classifications; and

(c)

complies with Clauses 7 to 15 inclusive of this Standard.

3 REFERENCED DOCUMENTS The following documents are referred to in this Standard: AS 1012 1012.13

Methods of testing concrete Method 13: Determination of the drying shrinkage of concrete for samples prepared in the field or in the laboratory

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AS 1012.20 1141 1141.3.1 1141.3.2 1141.4 1141.5 1141.6.1

Determination of chloride and sulfate in hardened concrete and concrete aggregates

1141.34 1141.35 1141.37

Methods for sampling and testing aggregates Method 3.1: Sampling— Aggregates Method 3.2: Sampling— Rock spalls, boulders and drill core Method 4: Bulk density of aggregate Method 5: Particle density and water absorption of fine aggregate Method 6.1: Par ticle density and w ater absorption of coarse aggregate — Weighing-in-water method Method 6.2: Par ticle density and w ater absorption of coarse aggregate — Pycnometer method Method 11: Particle size distribution by sieving Method 12: Material finer than 75 µm in aggregates (by washing) Method 13: Material finer than 2 µm Method 14: Particle shape, by proportional calliper Method 15: Flakiness index Method 22: Wet/dry strength variation Method 23: Los Angeles value Method 24: Aggregate soundness — Evaluation by exposure to sodium sulphate solution Method 25.1: Degradation factor — Source rock Method 26: Secondary mineral content in basic igneous rocks Method 30: Coarse aggregate quality by visual comparison Method 31: Light particles Method 32: Weak particles (including clay lumps, soft and friable particles) in coarse aggregates Method 34: Organic impurities other than sugar Method 35: Sugar Method 37: Iron unsoundness

1379

The specification and manufacture of concrete

3600

Concrete structures

4489 4489.7

Test methods for limes and limestones Method 7: Loss on ignition

AS/NZS ISO 9002

Quality systems for production and installation

ASTM C 294

Guide for Petrographic Examination of Aggregates for Concrete

1141.6.2 1141.11 1141.12 1141.13 1141.14 1141.15 1141.22 1141.23 1141.24 1141.25.1 1141.26 1141.30 1141.31 1141.32


Method 20:

AS 2758.1 — 1998

SAA HB18.25 HB79

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General requirements laboratories

for

the

competence

of

calibration

and

testing

Alkali Aggregate reaction—Guidelines on Minimising the Risk of Damage to Concrete Structures in Australia

DEFINITIONS For the purpose of this Standard the definitions below apply. NOTE: Appendix B provides some general definitions for reference purposes.

4.1

Aggregate

4.1.1 Coarse aggregate — aggregate having a nominal size greater than or equal to 5 mm. COPYRIGHT

AS 2758.1 — 1998

4.1.2

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Fine aggregate —aggregate having a nominal size of less than 5 mm.

4.1.3 Heavyweight aggregate — aggregate composed of inorganic materials having a particle density on a dry basis of greater than or equal to 3.2 t/m 3. 4.1.4 Lightweight aggregate — aggregate composed of materials having a particle density on a dry basis of less than 2.1 t/m 3 , and greater than or equal to 0.5 t/m 3. 4.1.5 Normal weight aggregate — aggregate composed of inorganic materials having a particle density on a dry basis of less than 3.2 t/m 3 and greater than or equal to 2.1 t/m 3 . 4.1.6 Ultra lightweight aggregate —aggregate composed of materials having a particle density on a dry basis of less than 0.5 t/m 3. 4.2 Bulk density — the mass of a unit volume of oven-dried aggregate. It may be determined for aggregate in either compacted or loose states (previously known as unit mass). 4.3 Nominal size — a designation of an aggregate which gives an indication of the maximum size particle present. The concept of nominal size is for convenience of reference and of ordering. 4.4 Particle density — the mass of the oven-dried particles divided by their saturated surface-dried volume (previously known as bulk density). 4.5 Recycled aggregate — crushed concrete composed of aggregate fragments coated with cement paste or cement mortar. 4.6 5

Single size aggregates — concrete single size aggregates are as defined in Table 1. SAMPLING

5.1 General The sampling of aggregate and of source rock shall be carried out in accordance with the methods described in AS 1141.3.1 and AS 1141.3.2 respectively. NOTE: The frequency of sampling should be nominated in the works specification.

5.2 Tender samples When required by the purchaser, tender samples shall be provided as evidence of the quality and grading of the materials proposed to be supplied. NOTE: The works specification may alternatively require the supplier to provide test data to indicate the quality and grading of the aggregate proposed for supply.

6 TESTING Testing of aggregates shall be carried out in accordance with the methods described in the relevant parts of AS 1141 and AS 1012, and in AS 4489.7. Proportions, ratios and percentages are expressed on the basis of mass.


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GENERAL REQUIREMENTS

7.1 Particle density When determined in accordance with AS 1141.5 for fine aggregate, and AS 1141.6.1 or AS 1141.6.2 for coarse aggregate, the particle density of the aggregate shall be as follows : (a)

For heavyweight aggregate, not less than 3.2 t/m 3.

(b)

For normal weight aggregate, less than 3.2 t/m 3 and greater than or equal to 2.1 t/m 3.

(c)

For lightweight aggregate, less than 2.1 t/m 3, and greater than or equal to 0.5 t/m 3.

(d)

For ultra lightweight aggregate, less than 0.5 t/m 3 .

7.2 Bulk density When determined in accordance with AS 1141.4 the compacted bulk density of lightweight aggregate shall be less than 1.2 t/m 3.

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AS 2758.1 — 1998

7.3 Water absorption Where specified, the percentage of water absorption shall be determined in accordance with AS 1141.5, AS 1141.6.1 or AS 1141.6.2. NOTES: 1 The maximum permissible water absorption should be nominated in the works specification. 2 The average absorption of aggregate, other than lightweight or vesicular, is about 2 percent. However, normal weight aggregates of higher absorption values may be acceptable based on local performance records and provided that the materials meet the requirements of Clauses 9 and 13. 3 The water absorption of lightweight or vesicular aggregates can exceed 2 percent considerably without affecting many of the properties of concrete made using such aggregates. To minimize any effect of absorption variations, it is recommended that lightweight and vesicular aggregates be pre-wetted prior to the commencement of the mixing process. 4 Owing to their cellular structure, lightweight or vesicular aggregates have a higher water absorption. Care must be exercised if water absorption is the result of deleterious mineralogy. Aggregates of this type should only be accepted if they comply with the requirements given in Clauses 9 and 13 or other durability tests specific for lightweight aggregate.

8 DIMENSIONAL REQUIREMENTS 8.1 Particle size distribution (grading) 8.1.1 General The supplier shall provide grading figures to indicate the average grading of the aggregate proposed for supply, which shall be known as the ‘submitted grading’. NOTE: The works specification may alternatively require the supplier to submit a sample the grading of which will be the basis for acceptance of the quotation, tender or source of supply. This sample is known as the ‘submitted sample’.


The ‘limits of deviation’ (see Tables 2 and 3) are the maximum variations in percentage between the submitted grading or the grading of the submitted sample and any particular test result during the course of the contract. NOTES: 1 Reasonably consistent grading is necessary for aggregate supplied under any one contract to ensure practical control of concrete manufacture. 2 It is recognized that smaller deviation values than those specified in Tables 2 and 3 may be more appropriate to particular projects. Where smaller deviations are required, values should be nominated in the works specification. 3 Provided that the concrete mix can be designed to achieve the required properties, satisfactory concrete may be made with aggregates with grading envelopes other than those given in Tables 1 and 3. For example — a) in some regions acceptable concrete is produced when the only fine aggregates available are finer than those given in Table 3; and b) Coarse aggregates differing from the gradings in Table 1 have been shown by experience to be acceptable for particular applications. Variations should be detailed in the works specification.

8.1.2 Coarse aggregate When determined in accordance with AS 1141.11, the grading of coarse aggregate supplied shall not deviate from the submitted grading, or the grading of the submitted sample, by more than the maximum permissible deviations given in Table 2. Unless otherwise specified, the grading shall conform to the respective overall limits for these materials given in Table 1. NOTE: Coarse aggregates of nominal sizes greater than 40 mm may be appropriate for use in specific work; e.g. dam construction and other mass concrete sections. Dimensional requirements suitable for concrete aggregates of nominal sizes greater than 40 mm do not form part of this Standard. COPYRIGHT

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8.1.3 Fine aggregate When determined in accordance with AS 1141.11, the grading of fine aggregate supplied shall not deviate from the submitted grading, or the grading of the submitted sample, by more than the maximum permissible deviations given in Table 3. Unless otherwise specified, the grading shall conform to the respective overall limits for these materials as specified in Table 3.

TABLE

1

COARSE AGGREGATE— GRADING REQUIREMENTS Mass of sample passing, percent Sieve aperture

Nominal size of graded aggregate mm*

Nominal size of single-size aggregates mm

40

28

20

14

40

28

20

14

10

7

5†

75.0 mm

100

—

—

—

100

—

—

—

—

—

—

53.0 mm

—

—

—

—

—

—

—

—

—

—

—

37.5 mm 85 to 100 26.5 mm

—

19.0 mm 30 to 70 13.2 mm

—

9.50 mm 10 to 35

100

—

—

85 to 100

100

—

—

—

—

—

85 to 100

100

—

—

85 to 100

100

—

—

—

—

—

85 to 100

100

0 to 20

—

85 to 100

100

—

—

—

25 to 60

—

85 to 100

—

0 to 20

—

85 to 100

100

—

—

—

25 to 55

—

0 to 5

—

0 to 20

—

85 to 100

100

—

6.70 mm

—

—

—

25 to 55

—

—

—

0 to 20

—

85 to 100

100

4.75 mm

0 to 5

0 to 10

0 to 10

—

—

0 to 5

0 to 5

—

0 to 20

—

85 to 100

2.36 mm

—

0 to 5

0 to 5

0 to 10

—

—

—

0 to 5

0 to 5

0 to 20

0 to 40

75 µm‡

0 to 2

0 to 2

0 to 2

0 to 2

0 to 2

0 to 2

0 to 2

0 to 2

0 to 2

0 to 2

0 to 2

* Single-size aggregate should always be specified where strict control of grading and of concrete mix design is considered essential. Graded aggregates are considered more susceptible to segregation in transport and handling, and may introduce difficulties in uniform concrete production. † Although 5 mm nominal size is defined as coarse aggregate, it is often used in concrete as a fine aggregate.


‡ See Clause 8.2. In addition, where coarse aggregates contain more than about 1 percent of material passing the 75 µm sieve, particular care should be taken to remix or wash this material to minimize the effect of segregation.

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AS 2758.1 — 1998

TABLE

2

COARSE AGGREGATE— LIMITS OF DEVIATION Limits of deviation, percent† Sieve aperture

Nominal size of graded aggregate, mm

Nominal size of single-size aggregate, mm

40

28

20

14

40

28

20

14

10

7

5

75.0 mm

—

—

—

—

—

—

—

—

—

—

—

53.0 mm

—

—

—

—

—

—

—

—

—

—

—

37.6 mm

±10

—

—

—

±10

—

—

—

—

—

—

26.5 mm

±15

±10

—

—

±10

±10

—

—

—

—

—

19.0 mm

±15

±15

±10

—

±10

±10

±10

—

—

—

—

13.2 mm

±10

±15

±15

±10

±5

±10

±10

±10

—

—

—

9.50 mm

±10

±10

±15

±15

—

±5

±10

±10

±10

—

—

6.70 mm

±5

±10

±10

±15

—

±5

±5

±10

±10

±10

—

4.75 mm

—

±5

±5

±5

—

—

—

±5

±10

±10

±10

2.36 mm

—

—

—

—

—

—

—

—

—

±10

±10

75 µm*

—

—

—

—

—

—

—

—

—

—

—

* See Clause 8.2. † Limits of deviation on the submitted grading or the grading of the submitted sample (see Clause 8.1.1).

TABLE

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FINE AGGREGATE — GRADING REQUIREMENTS AND LIMITS OF DEVIATION


Uncrushed fine aggregate

Crushed fine aggregate

Sieve aperture

Mass of sample passing, percent

Maximum deviation, percent

Mass of sample passing, percent

Maximum deviation, percent

9.50 mm

100

—

100

—

4.75 mm

90 to 100

±5

90 to 100

±5

2.36 mm

60 to 100

±5

60 to 100

±10

1.18 mm

30 to 100

±10

30 to 100

±15

600µm

15 to 100

±15

15 to 80

±15

300 µm

5 to 50

±10

5 to 40

±10

150 µm

0 to 20

±5

0 to 25

±5

75 µm*

0 to 5

—

0 to 20

±5

* See Clause 8.2.

8.2

Material finer than 75 µm

8.2.1 Coarse and fine aggregates When determined in accordance with AS 1141.11 or AS 1141.12, the quantity of material finer than 75 µm in each component of a blend shall not exceed the limits in Tables 1 and 3 for each component. 8.2.2 Material finer than 2 µm When determined in accordance with AS 1141.13, the quantity of material finer than 2 µm shall not exceed 1 percent for each of the coarse and fine aggregates. COPYRIGHT

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8.3 Particle shape in coarse aggregate Unless otherwise specified, the proportion of misshapen particles in coarse aggregate retained on the 9.50 mm test sieve shall not exceed 10 percent when determined in accordance with AS 1141.14 using a 3:1 ratio or the flakiness index shall not exceed 35 percent when determined in accordance with AS 1141.15. NOTES: 1

In some areas the available aggregate may not comply with the shape requirements set out above. In such cases, acceptance of the aggregate should be related to the purpose for which the concrete is to be used and to the design of the mix.

2

At the option of the purchaser, alternative limits may be specified for one or more of the following — (a) the appropriate proportion of misshapen particles determined in accordance with AS 1141.14, using a 2:1 ratio; (b) the appropriate proportion of flat particles determined in accordance with AS 1141.14, using a 2:1 ratio; and (c) the appropriate proportion of elongated particles determined in accordance with AS 1141.14, using a 2:1 ratio.

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DURABILITY

9.1 General Aggregate durability limits are given in Clauses 9.2 and 9.3 for the exposure classification or the environment of the worst exposed concrete surface in which the aggregate is intended to be used. A full description of the exposure classification is given in Appendix A. Aggregate durability specifications shall be provided in the works specification.


NOTES: 1

Aggregates conforming with the requirements of this Clause are expected to have sufficient durability to withstand the conditions of the relevant exposure classification of the concrete member for an estimated design life of 40 to 60 years. More stringent requirements than those specified for the particular exposure classification would be required for a design life exceeding 60 years.

2

Aggregate durability characteristics should not be taken as a direct predictor of the mechanical and physical properties of the concrete. The true impact of the aggregate on concrete properties can only be evaluated effectively in concrete mix trials.

3

Classification U in Appendix A represents an exposure environment not specified in Tables A1 and A2 but for which a degree of severity of exposure should be assessed and appropriate durability limits provided in the works specification.

9.2 Fine aggregates All fine aggregate intended for use in concrete exposure classifications C and B2 shall show a weighted average loss not greater than 12 percent, when determined in accordance with AS 1141.24. Crushed fine aggregate intended for use in concrete subject to exposure classifications A1, A2 and B1 shall show a weighted average loss not greater than 15 percent, when tested in accordance with AS 1141.24. Uncrushed fine aggregates complying with all other requirements of this Standard will generally possess sufficient durability to permit satisfactory use in concrete subject to exposure classifications A1, A2 and B1 (see Notes 1, 2 and 3). NOTES: 1

Experience has shown that uncrushed fine aggregates have generally sustained substantial weathering in their natural environment and rarely require durability testing.

2

Other test methods of particular relevance to quality of fine aggregate for concrete are materials finer than 2 µm (see Clause 8.2.3), and light particles (see Clause 12) and test methods on reactive materials and impurities (see Clauses 10 and 14). COPYRIGHT

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9.3

AS 2758.1 — 1998

Fine aggregates have been found to significantly influence the abrasion and skid resistance of concrete. Additional properties may need to be specified in the works specification where abrasion and skid resistance of the finished concrete are important.

Coarse aggregates

9.3.1 General The method of assessment of the durability of coarse aggregates shall be one of those given in Clauses 9.3.2, 9.3.3 or 9.3.4. NOTES: 1

The method of assessment would normally be specified in the works contract and should be chosen on the basis that it has been shown by experience to be appropriate for the rock sources to be used. In some cases experience may show that the pass criteria needs to be adjusted for a particular rock source or the end use intended.

2

Various authorities in Australia have adopted and developed test methods or sets of test methods for the assessment of the durability of aggregates, based on correlations between the observed durability of aggregates in service and the results of their assessment procedures. Each of these procedures has been shown to be valid for a limited range of rock sources located primarily within the areas of control of the authority using the particular procedure. Certain supporting overseas data is also available but climatic and use conditions may be different to the conditions experienced in Australia. The three sets of methods represent those most commonly used in Australia.

9.3.2 Wet strength and wet/dry strength variation The wet strength and wet/dry strength variation of aggregate, when determined in accordance with AS 1141.22, shall comply with the appropriate limits given in Table 4. TABLE

4

WET STRENGTH AND WET/DRY STRENGTH VARIATION Concrete exposure classification

Minimum wet strength kN

Maximum wet/dry strength variation percent

A1, A2

50

45

B1, B2

80

35

C

100

25


NO TE: For some aggregates other values could be adopted in Table 4, for example in wet/dry strength variation for concrete exposure classification C. Any changes should be based on satisfactory local experience of materials and performance.

9.3.3 Los Angeles value and sodium sulfate soundness The Los Angeles value of the aggregates, when determined in accordance with AS 1141.23, shall comply with the appropriate limits given in Table 5 and the sodium sulfate soundness, when determined in accordance with AS 1141.24, shall show a weighted average loss not greater than the values given in Table 6. NOTES: 1

Some coarse-grained rocks, e.g. granite, have been known to lose whole crystals during the Los Angeles value test procedure. Care should be exercised when interpreting the results of tests from a quarry containing rock of this type.

2

For some aggregates other values could be adopted than those given in Table 5 based on satisfactory local experience of materials and performance, e.g. vesicular aggregates.

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AS 2758.1 — 1998

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12

Outright rejection of aggregates is not recommended based solely on the results of AS 1141.24. Confirmation of the aggregates unsuitability should be sought using other tests more closely related to the specific service intended.

TABLE

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LOS ANGELES VALUE Maximum Los Angeles value, percent loss Rock type

Concrete exposure classifications A1, A2

B1, B2, C

Coarse grained (see Notes 1 and 2)

40

35

All other rocks

35

30

TABLE

6

SODIUM SULFATE SOUNDNESS Concrete exposure classification

Maximum weighted average loss percent

A1, A2

12

B1, B2

9

C

6

9.3.4 Los Angeles value and unsound and marginal stone content The Los Angeles value, when determined in accordance with AS 1141.23, shall comply with the appropriate limits given in Table 5 and the unsound stone content, when determined in accordance with AS 1141.30, shall not exceed the following values — (a)

unsound stone content

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 percent; and

(b)

total of unsound stone content and marginal stone . . . . . . . . . . . . . . . 10 percent.

NOTE: Some rock sources contain secondary minerals or exhibit other properties which may affect the long-term durability of the product and give rise to poor service performance. AS 1141.30 provides a method for visual comparison with reference specimens to allow visual comparisons and quality assessments. Suggested values of degradation factor, when determined in accordance with AS 1141.25, and secondary mineral content, when determined in accordance with AS 1141.26, used to classify the reference specimens are as follows:


Rock type Basic igneous: (a) Sound (b) Marginal Other igneous and metamorphic

Degradation factor

Secondary mineral content*, percent

≥ 50 ≥ 30 ≤ 49

≤ 25 ≥ 26 ≤ 30

†

Not required

* Basic igneous source rock which does not comply with specified secondary mineral content requirements but from which aggregates of proven satisfactory performance have been produced may be acceptable. † Degradation factor values for rock types other than basalts should be based on satisfactory local service and should be included in the works specification.

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10

AS 2758.1 — 1998

ALKALI-REACTIVE MATERIALS

10.1 General Aggregates intended for use in concrete that will be subjected to frequent wetting, extended exposure to humid atmosphere, or contact with moist ground, shall not react with alkalis in the concrete to an extent that may result in excessive expansion. 10.2 Requirements The supplier shall provide appropriate documentation to allow assessment of the potential reactivity of the aggregate. The works specification shall define the method of assessment and the test methods to be used. NOTE: Guidance on assessment and mix design is given in SAA HB79.

11 WEAK PARTICLES IN COARSE AGGREGATE When coarse aggregate is tested in accordance with AS 1141.32, the proportion of weak particles shall not exceed 0.5 percent. 12 LIGHT PARTICLES Except for lightweight aggregates and ultra lightweight aggregates, materials of particle density less than 2.0 t/m 3 in the total fine and coarse aggregate shall not exceed 1 percent by mass when determined in accordance with AS 1141.31. For vesicular aggregates, a limit of 3 percent is permissible. NOTE: Light particles, particularly of wood, coal, charcoal and the like, tend to rise to the surface during vibration of concrete used in horizontal surfaces such as pavements and floors. The permissible limit of 1 percent, while not affecting the strength of concrete, will produce very poor surface finishes under the above conditions. For such work a lower limit may be specified.

13 DRYING SHRINKAGE Except where the potential contribution of fine and coarse aggregates to the shrinkage of concrete has been tested for a particular concrete mix in accordance with AS 1012.13, the following materials shall not be used as aggregates (see Notes 1, 2 and 3): (a)

Volcanic breccia.

(b)

Mudstone.

(c)

Sandstone.

(d)

Shale.

(e)

Highly weathered or altered rocks.


NOTES: 1

The degree of shrinkage of concrete depends on a number of factors which are related to the particular mix. These include the influence of the water demand of the mix, cement characteristics and aggregate characteristics. The concrete shrinkage is dependent on the individual factors and their interaction (see AS 1379 for full discussion of the various factors).

2

Aggregate assists in resisting the shrinkage of the cement paste if it has a high modulus but may contribute to the shrinkage of concrete when the minerals comprising the rock substance include swelling clays or the rock substance itself has a capacity to absorb water. With the exception of lightweight aggregate, absorptions of about 2 percent are average, so values in excess of this are more likely to be associated with higher than average concrete shrinkage.

3

Grading, shape and texture of aggregate, particularly fine aggregate, influence water demand in concrete and therefore influence concrete shrinkage.

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14

IMPURITIES

14.1 Organic impurities Where fine aggregate is tested in accordance with AS 1141.34, the colour obtained shall not be darker than the standard colour of the reference solution. NOTE: The performance of the suspect sand may be evaluated by comparing its performance in concrete to that of a similar concrete manufactured using a known satisfactory fine aggregate.

14.2 Sugar When tested in accordance with AS 1141.35, the aggregate shall test negative to the presence of sugar. 14.3

Soluble salts

NOTE: Excessive quantities of some soluble salts may cause efflorescence on the concrete, corrosion of the reinforcing steel or disintegration of the mass of the concrete. Permissible levels of soluble salts are generally expressed as the proportion of the relevant ion present in the concrete by mass of concrete or by mass of portland cement.

14.3.1 Chlorides The chloride ion content of aggregates determined quantitatively in accordance with AS 1012.20 shall be reported if in excess of 0.01 percent (see Note). NOTE: A combination of aggregates where the total chloride salt content (expressed as Cl -) exceeds 0.04 percent should not be used in reinforced concrete. A combination of aggregates where the total chloride salt content exceeds 0.15 percent should not be used in plain concrete.

14.3.2 Sulfates The sulfate ion content of aggregates determined quantitatively in accordance with AS 1012.20 shall be reported if in excess of 0.01 percent (see Note). NOTE: Aggregates should not be used which, when tested in accordance with AS 1012.20, contain sulfates (expressed as SO 3) in proportions which result in the sulfate content of the concrete mix exceeding 5.0 percent by mass of portland cement.

14.3.3 Other salts Aggregates which contain other strongly ionized salts, such as nitrates, shall not be used unless it can be shown that they do not adversely affect concrete durability. Restrictions on the presence of these salts may be specified in the works specification. 15

ADDITIONAL REQUIREMENTS FOR SLAG AGGREGATES

15.1 Iron unsoundness When chemical analysis of the slag shows that the ferrous oxide content equals or exceeds 3 percent and the sulfur content equals or exceeds 1.0 percent, the aggregate should be tested for iron unsoundness.


If the iron unsoundness of the slag, when tested in accordance with AS 1141.37, exceeds 1 percent it shall not be used as a concrete aggregate. NOTE: Iron unsoundness has not been recorded for Australian iron blast furnace slag. Iron unsoundness which is manifested by disintegration of the slag on immersion in water is highly likely when the iron blast furnace slag contains more than the above limits for ferrous oxide and sulfur.

15.2 Falling or dusting unsoundness Fresh slag shall only be used as an aggregate in concrete if it has been allowed to cool to below 50°C. NOTE: During the cooling of some blast furnace slag the inversion at around 490°C of any beta dicalcium silicate in the slag to the gamma form, may result in disruption of the slag mass. This disruption leads to what is known as falling or dusting unsoundness. Any beta dicalcium silicate that is retained in the cooled slag is considered to be kinetically stable and will not invert to cause disruption of the slag. No evidence has been found either in Australia or overseas of delayed inversion of beta dicalcium silicate in iron blast furnace slag, or of deterioration of concrete due to the presence of beta dicalcium silicate.

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AS 2758.1 — 1998

15.3 Stockpiling of iron blast furnace slag aggregate Crushed blast furnace slag aggregate intended to be used in concrete shall be stockpiled in moist condition at or near the saturated surface dry condition, prior to use. The moisture condition shall be maintained by sprinkling with water. Prior to use of blast furnace slag from a new source or when significant changes in furnace chemistry occur in an existing source which may result in the presence of free lime, the potential for pop-out formation shall be assessed by determining the free-lime content of the slag by petrographic examination or quantitive x-ray diffractometry on a representative sample obtained in accordance with AS 1141.3.1. If the level of particles containing free lime exceeds 1 in 20 then stockpiling of the slag represented by the tested sample shall be continued under the above moisture conditions until further testing shows that the level has fallen below 1 in 20. NOTE: The previous requirement of prolonged weathering of the aggregate was designed to eliminate the occurrence of ‘pop-outs’ in the concrete containing the slag aggregate resulting from the incomplete assimilation of the calcined limestone in the blast furnace. Modern blast furnace practice in Australia is intended to ensure all flux materials including limestone are fully assimilated into the molten slag. Where that is achieved no unassimilated particles of calcined limestone are present in the solidified slag. Hence the occurrence of popouts as a result of the hydration of these particles cannot occur.

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ADDITIONAL REQUIREMENTS FOR LIGHTWEIGHT AGGREGATES

16.1 Weak particles When coarse lightweight aggregate is tested in accordance with AS 1141.32, the proportion of weak particles shall not exceed 2 percent. 16.2 Loss on ignition When determined generally in accordance with AS 4489.7, lightweight aggregates shall not show loss on ignition by mass in excess of 5 percent. NOTE: Certain processed aggregates may be hydrated during production; if so, the quality of the product is not reduced thereby. Other aggregates may in their natural states contain innocuous carbonates or water of crystallization, which will contribute to the loss on ignition. Therefore, consideration should be given to the type of material when evaluating the product in terms of ignition loss.


16.3 Variation of bulk density The maximum permissible deviation of the compacted bulk density shall not exceed 10 percent of the compacted bulk density of the tender sample or nominated density.

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APPENDIX A

EXPOSURE CLASSIFICATIONS (Normative) The exposure classification for an aggregate shall be determined from Table A1, Table A2 and Figure A1. The exposure classification of a concrete member shall be taken as the most severe exposure of any of its surfaces. The exposure conditions are classified A to C in increasing order of their aggressiveness to the concrete element or structure. There are no limits given in Clause 9 for the classification U. TABLE

A1

EXPOSURE CLASSIFICATIONS

Surface and exposure environment

Exposure classification All concrete types


1 Surfaces of members in contact with the ground (a) Members protected by a damp-proof membrane (b) Residential footings in non-aggressive soils (c) Other members in non-aggressive soils (d) Members in aggressive soils

A1 A1 A2 See Table A2

2 Surfaces of members in interior environments (a) Fully enclosed within a building except for a brief period of weather exposure during construction (b) In industrial buildings, the member being subject to repeated wetting and drying

A1

3 Surfaces of members in above-ground exterior environments In areas that are: (a) Inland (> 50 km from coastline) environment being— (i) non-industrial and arid climatic zone (Notes 3 and 4) (ii) non-industrial and temperate climatic zone (iii) non-industrial and tropical climatic zone (iv) industrial and any climatic zone (b) Near coastal (1 km to 50 km from coastline), any climatic zone (c) Coastal (up to 1 km from coastline but excluding tidal and splash zones) (Note 5), any climatic zone

A1 A2 B1 B1

4 Surface of members in water (a) In fresh water (b) In sea water— (i) permanently submerged (ii) in tidal or splash zones (c) In soft or running water

B1

B1 B2 B1 B2 C B1–C

5 Surfaces of members in other environments Any exposure environment not otherwise described in Items 1 to 4 above

U

NO TES: 1 In this context, reinforced concrete includes any concrete containing metals which rely on the concrete for protection against environmental degradation. Plain concrete members containing reinforcement or other metallic embedments should therefore be treated as reinforced members when considering durability.

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AS 2758.1 — 1998

2 The climatic zones referred to are those given in Figure A1, which is a simplified version of Plate 8 of the Bureau of Meteorology publication, ‘Climate of Australia’, 1982. 3 ‘Industrial’ refers to areas that are within 3 km of industries that discharge atmospheric pollutants. 4 For the purpose of this Table, the coastal zone includes locations within 1 km of the shoreline of large expanses of salt water (e.g. Port Phillip Bay, Sydney Harbour east of the Spit and Harbour bridges, Swan River west of the Narrows Bridge). Where there are strong prevailing winds or vigorous surf, the distance should be increased beyond 1 km and higher levels of protection should be considered. Proximity to small saltwater bays, estuaries and rivers may be disregarded.

TABLE

A2

EXPOSURE CLASSIFICATION — GROUND WATER All concrete types Nature of ground water in contact with concrete surface

Low permeability soil e.g. clay

High permeability soil e.g. sand

Resistivity when damp (10 to 30Ω.m)

B1

B2

Resistivity when damp < 10Ω.m

B1

C

SO 4 < 1000 ppm

B1

B2

SO 4 1000 − 6000 ppm

B2

C

SO 4 > 6000 ppm

C*

C*

C

U†

Saline (chloride containing soils)

Sulfate-containing soils (See Note)

Acidic soils pH < 4.0

* Particularly in high and very high salinity soils which are permeable, evaporation and capillary action can result in spalling of concrete protruding above the ground. Therefore, consideration should be given to installing a membrane or adding an effective waterproofing agent. † For these situations, considerations should be given to the use of sacrificial aggregates.


NO TE: Equivalent sulfur trioxide SO3 = 0.83 × sulfate ion SO 4.

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CLIMATIC ZONES REFERRED TO IN TABLE A1


FIGURE A1

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AS 2758.1 — 1998

APPENDIX B

TERMINOLOGY AND CLASSIFICATION (PETROLOGICAL) (Informative) B1 INTRODUCTION Identification of the rock types which are to be used in the production of aggregate may provide an initial indication of suitability for purpose. However, it should be emphasized that rock type identification cannot substitute for the performance of the engineering tests detailed in this Standard. Nor can it be implied that because two sources have a similar rock type identification, they will have the same engineering properties. In most rocks the engineering properties are influenced by the primary mineralogy, the grain size and rock structure, secondary and adverse mineralogy, and the degree of weathering. Table B1 and Table B2 provide an aid to identification of sedimentary, igneous and metamorphic rocks in sufficient detail for the purposes of this Standard. They follow general geological practice, but are intended as a guide only; geological training is required for the satisfactory identification of rocks. Engineering properties cannot be inferred from rock names in the tables. Table B3 provides a general description of the more common rock types which may be used for aggregate in Australia. For details on primary and secondary mineralogy and some information on the effects of mineralogy on the engineering properties of aggregate, reference should be made to ASTM C 294. NOTES to Tables B1 and B2: 1

Principal rock types (generally common) are shown in bold type in capitals, e.g. GRANITE. Less common rock types are shown in lower case, e.g. Greywacke.

2

Granular rocks may be distinguished from crystalline rocks by scratching with a knife, which should remove whole grains from cement matrix in the granular rocks. The separate grains may also sometimes be distinguished using a hand lens. Siliceous rocks are generally harder and more resistant to scratching than calcareous rocks.


3

In the Tables the boundaries of the heavy lined box describe the conditions to which the rock name applies.

B2 PARTICLE SHAPE AND SURFACE TEXTURE OF AGGREGATE The important external characteristics of the particles of mineral aggregates include their shape and surface texture. To avoid lengthy descriptions, it is convenient to classify these properties under a number of simple headings. The system shown in Tables B4 and B5 has been devised for this purpose. Characteristic specimens are illustrated in Figure B1 and tests for obtaining quantitative assessment of particle shape are given in AS 1141.14.

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TABLE

B1

AN AID TO IDENTIFICATION OF ROCKS FOR ENGINEERING PURPOSES (SEDIMENTARY ROCKS) Tables B1 and B2 follow general geological practice, but are intended as a guide only; geological training is required for the satisfactory identification of rocks. Engineering properties cannot be inferred from rock names in the Table. Gr ain size mm Gr ain size de scr iption

At least 50% of grains are of carbonate

CONGLOMERATE Rounded boulders, c obbles a nd grave l c em ented in a finer m atrix

6__

Fragm ents of volca nic ejec ta in a finer ma trix

Brecc ia Irregular rock fragme nts in a finer ma trix

Fine

Medium

ARENACEOUS

0.2__

0.002__

Le ss than 0.002__


Amorphous or cryptocr ystalline

ARGILLACEOUS

0.06__

SANDSTONE Angular or rounded grains, commo nly c eme nted by clay, ca lcitic or iron minerals Quartzite Quartz grains and siliceo us ce me nt Arkose Ma ny fe ldspar grains

Calcirudite*

SALINE ROCKS

Rounded grains AG GLOMERATE

Ha lite

Angular grains VO LCANIC BRECCIA

Anhydrite

Cemen ted volca nic as h

Gypsum

Calca renite

TUFF

Calcisiltite

Fine-grained TUFF

Greywack e Ma ny rock chips

MUDSTONE

SILTSTONE Mostly silt

SH ALE Fiss ile

CLAYSTONE Mostly cla y

Calcareous mudstone

Coarse

2__

0.6__

At least 50% of grains are of fine grained volcanic rock

CHALK

RUDACEOUS

20__

LIMESTONE and DOLOMITE (undifferentiated)

More than 20

Bedde d roc ks (mostly se dimen tary)

Calcilutite

Ve ry fine-grained TUFF

Flint: occu rs as bands of nodules in the c halk

CO AL

Chert: occ urs as nodules a nd beds in limestone a nd c alc ar eous san dstone

LIGNI TE

Granular c eme nted— e xce pt a morphous rocks

SILICEOU S

CALCAREOUS

SILICEOU S

CARBONACEOU S

SE DIMENT ARY ROCKS Granular c eme nted rocks vary greatly in strength, some san dstones a re stronger than m any igneous rocks . Bedding m ay not show in hand spec imens and is bes t seen in outcrop. Only sedime ntary rocks, a nd some me tamorphic rocks derived from them, contain foss ils. Calca reous rocks contain c alc ite (c alcium car bonate) which efferves ces with dilute hydrochloric a cid.

* A more detailed classification is given in Clark, A.R. and Walker, B.F. Geotechnique , 1977, 27(1), 93-99. COPYRIGHT

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AS 2758.1 — 1998

TABLE

B2

AN AID TO IDENTIFICATION OF ROCKS FOR ENGINEERING PURPOSES (METAMORPHIC AND IGNEOUS ROCKS)

Ob viously foliated r ocks (mostly met amorph ic)

Rocks with massive stru ct ure and cr ystalline textur e (mostly igneous)

Gr ain size de scr iption

COARSE

Gr ain size de scr iption

GNEISS We ll developed but often widely spac ed foliation sometimes with sc histose bands

Migma tite Irregularly foliated: mixed sch ists a nd gneisses

Gr ain size mm

Pyroxenite

Pe gma tite

__20

MARBLE COARSE

GR ANITE1

Diorite 1,2

GA BBRO 3

Pe ridotite

QUARTZITE

__6

Granulite

These rocks ar e sometimes porphyritic and ar e then desc ribed, for e xam ple, a s porphyritic gra nite

HO RNF ELS

MEDIUM

SCHIS T We ll developed undulose foliation; generally much mica

Amphibolite

More than 20

__2

MEDIUM

Microgranite 1

Microdiorite 1,2

Dolerite 3,4 __0.6

Se rpentine These rocks ar e sometimes porphyritic and ar e then desc ribed as porphyries

__0.2

__0.06

FINE

RH YOLITE 4,5

PH YLLITE Slightly undulose foliation; sometimes ‘spotted’

__0.002

These rocks ar e sometimes porphyritic and ar e then desc ribed as porphyries

Mylonite Found in fault zones , ma inly in igneous and me tamorphic ar eas

Obsidian 5

CRYST ALL INE Pa le


BASALT 4,5

FINE

SLATE We ll developed plane cleav age (foliation)

SILICEOU S

ANDESITE 4,5

Ma inly SILICEOU S

METAMORPHIC ROCKS Most m etamo rphic rocks ar e distinguished by foliation which ma y impart fissility. Foliation in gneisse s is best obser ved in outcrop. Non-foliated m eta morphics ar e difficult to reco gnise excep t by as soc iation. Any rock baked by contact me tamorphism is des cr ibed as a ‘hornfe ls’ and is genera lly somew hat stronger than the parent rock.

ACID Much quartz

Le ss than __0.002 Am orphous or cryptocr ystalline

Volca nic glass

colour -------------------------------------

INTER MEDIATE Some quartz

BASIC Little or no quartz

Da rk

UL TRA BASIC

IGNEO US ROCKS Composed of close ly interlocking m inera l grains. Strong when fresh; not porous Mode of occ urrence: 1 Batholiths; 2 L acc oliths; 3 Sills; 4 Dykes; 5 La va flows; 6 Veins

Most fre sh m eta morphic rocks are strong although perhaps fissile.

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TABLE

B3

ROCK TYPES COMMONLY USED FOR AGGREGATES Petrological term

Description

Andesite *

A fine-grained rock, usually volcanic, similar in composition to diorite

Arkose

A type of sandstone or gritstone containing over 25% feldspar

Basalt

A fine-grained basic rock, similar in composition to gabbro, usually volcanic

Breccia†

Rock consisting of angular, unworn rock fragments, bonded by natural cement

Calcrete (var.

A rock type formed from soil or rock fragments cemented with calcite


cali che)

Chert

Cryptocrystalline‡ silica

Conglomerate†

Rock consisting of rounded pebbles in a finer matrix bonded by natural cement

Dacite*

A fine-grained intermediate rock having a composition in between rhyolite and andesite

Diorite

An intermediate plutonic rock, consisting mainly of plagioclase, with hornblende, augite or biotite

Dolerite

A basic rock, with grain size intermediate between that of gabbro and basalt

Dolomite

A rock or mineral composed of calcium magnesium carbonate

Gabbro

A coarse-grained, basic, plutonic rock, consisting essentially of calcic plagioclase and pyroxene, sometimes with olivine

Gneiss

A banded rock, produced by intense metamorphic conditions

Granite

An acidic, plutonic rock, consisting essentially of alkali feldspars and quartz

Granulite

A metamorphic rock with granular texture and no preferred orientation of the minerals

Greywacke

An impure type of sandstone or gritstone, composed of poorly sorted fragments of quartz, other minerals and rock; the coarser grains are usually strongly cemented in a fine matrix

Hornfels

A thermally metamorphosed fine grained rock containing substantial amounts of rock-forming silicate minerals

Limestone

A sedimentary rock, consisting predominantly of calcium carbonate

Marble

A metamorphosed limestone

Microgranite *

An acidic rock with grain size intermediate between that of granite and rhyolite

Quartzite

A metamorphic rock or sedimentary rock, composed almost entirely of quartz grains

Rhyolite *

A fine-grained or glassy acidic rock, usually volcanic

Sandstone

A sedimentary rock, composed of sand grains naturally cemented together

Schist

A metamorphic rock in which the minerals are arranged in nearly parallel bands or layers. Platy or elongated minerals such as mica or hornblende cause fissility in the rock which distinguishes it from a gneiss

Serpentinite

A metamorphic rock type consisting predominantly of serpentine. The rock is derived from metamorphism of ultra-basic or silicified limestone parent rocks (continued)

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TABLE Petrological term Slag

B3

AS 2758.1 — 1998

(continued) Description

Typically a silica and calcium rich residue of metal smelting process. For the purposes of this Standard, slags are classified as ferrous or non-ferrous as follows: (a)

Iron blast furnace slag aggregates — slag produced in the production of iron, consisting essentially of silicates and alumino-silicates of calcium and other bases. By influencing the cooling conditions and cooling rates, the molten blast furnace slag can solidify to the following products with their own distinctive physical properties: (i)

Crystalline slag — results from the solidification of molten slag under atmospheric conditions in pits or bays. Cooling may be subsequently accelerated by application of water to the solidified surface.

(ii)

Granulated slag — refers to the glassy granular material formed when molten slag is rapidly chilled by the impingement of and mixing with a large volume of water.

(b)

Non-ferrous metallurgical slag aggregate — slag produced from smelting processes for metals such as copper, lead and nickel.

(c)

Steel furnace slag — steel furnace slag is the non-metallic product consisting essentially of calcium silicates and ferrites combined with fused oxides of iron, aluminium, manganese, calcium and magnesium, that is developed in a molten condition simultaneously with steel in a basic oxygen or electric arc furnace.

Slate

A rock derived from argillaceous sediments or volcanic ash by metamorphism, characterized by cleavage planes independent of the original stratification

Silcrete

A rock type formed from soil or rock fragments cemented with silica

Syenite

An intermediate plutonic rock, consisting mainly of alkali feldspar with plagioclase, hornblende, biotite, or augtite

Trachyte *

A fine-grained rock, usually volcanic, similar in composition to syenite

Tuff

Consolidated volcanic ash

*


The terms microgranite, dacite, rhyolite, andesite, or trachyte, as appropriate, are preferred for rocks alternatively described as porphyry or felsite. † Some terms refer to structure or texture only, e.g. breccia or conglomerate, and these terms cannot be used alone to provide a full description. ‡ Composed of crystals so fine that they can be resolved only with the aid of a high-power microscope.

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TABLE

B4

PARTICLE SHAPE* Classification

Description

Rounded

Fully water-worn or completely shaped by attrition

Irregular

Naturally irregular, or partly shaped by attrition and having rounded edges

Angular

Possessing well-defined edges formed at the intersection of roughly planar faces

Flaky

Material of which the thickness is small relative to the other two dimensions

Elongated

Material, usually angular, in which the length is considerably larger than the other two dimensions

Flaky and elongated

Material having the length considerably larger than the width, and the width considerably larger than the thickness

* See also Figure B1.

TABLE

B5

SURFACE TEXTURE Surface texture group *

Characteristics

Glassy

Conchoidal fracture

Smooth

Water-worn, or smooth due to fracture of laminated or finegrained rock

Granular

Fracture showing more or less uniform rounded grains

Rough

Rough fracture of fine-grained or medium-grained rock containing no easily visible crystalline constituents

Crystalline

Containing easily visible crystalline constituents

Honeycombed

With visible pores and cavities

* The surface texture grouping is broad, being based on the impression that would be gained by a visual examination of hand specimens.


It should be noted that different specimens of the same rock type may not fall into the same group.

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Flaky

Elongated

Flaky and Elongated

Angular

Blocky cubical

Sub-rounded


Rounded

Irregular

FIGURE B1

TYPICAL PARTICLE SHAPES

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As 2758.1-1998 Concrete Aggregates

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