Cadeby dimension limestone technical report

Cadeby Stone Limited Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

Cadeby Stone Limited Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

February 2004

Ove Arup & Partners Ltd 13 Fitzroy Street, London W1T 4BQ Tel +44 (0)20 7636 1531 Fax +44 (0)20 7755 3626 www.arup.com

Job number

113059-00

Document Verification Page 1 of 1

Cadeby limestone

Job title

Job number

113059-00 Document title

Assessment of Cadeby limestone for use as dimension stone

Document ref

001

Revision

Filename

Date

Draft 1 15/08/03

Description

Name

File reference

Cadeby limestone draft report 040703.doc First draft

Prepared by

Checked by

Approved by

Darren Anderson

Bruno Miglio

Bruno Miglio

Signature

Issue

071103

Description

Cadeby limestone issue 071103.doc Issue copy

Prepared by

Checked by

Approved by

Name

Darren Anderson

Bruno Miglio

Bruno Miglio

Filename

Signature

Issue 2 02/02/04

Description

Cadeby limestone issue 2 020204.doc Issue copy . Additional paragraph to section 1.

Prepared by

Checked by

Approved by

Name

Darren Anderson

Bruno Miglio

Bruno Miglio

Prepared by

Checked by

Approved by

Filename

Signature Filename Description

Name Signature

Issue Document Verification with Document

9

ŠArup F8.5 QA Rev 1/01 1 November 2001

C:\DOCUMENTS AND SETTINGS\FRANCES.CONDON\DESKTOP\CADEBY.DOC

Ove Arup & Partners Ltd Issue 2 February 2004

Cadeby Stone Limited

Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

CONTENTS Page 1.

INTRODUCTION

1

2.

2.1 2.2

BACKGROUND Geology Previous uses

2 2 2

3.

3.1 3.2 3.3 3.4 3.5

QUARRY Location Source of dimension stone Transportation routes Block extraction Fabrication works

3 3 3 3 3 3

4.

4.1 4.2 4.3 4.4

TECHNICAL PROPERTIES Test regime Cadeby White - Results and Interpretation Cadeby Light Gold - Results and Interpretation Cadeby Brown - Results and Interpretation

5 5 6 10 14

5.

APPROPRIATE THICKNESS OF STONE FOR CLADDING DESIGN

18

6.

6.1 6.2

SUMMARY General Technical Properties

19 19 19

FIGURES

20

Ove Arup & Partners Ltd Issue 2 February 2004

Cadeby Stone Limited

1.

Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

INTRODUCTION During 2002, Cadeby Stone Limited (CSL) obtained the lease to extract the limestone from Cadeby quarry for use as dimension stone. In recent years, the stone has been used on a small scale in a number of stone cladding projects. CSL hope to increase production and are assessing the suitability of the material for use on larger cladding and flooring/paving projects, both internally and externally. As part of this study, CSL have commissioned Arup Materials Consulting (AMC) to undertake a brief assessment of the quarry and the blocks extracted from it, and to review recent test data obtained from blocks of Cadeby stone.

This report is written for Cadeby Stone Limited and is solely for their use. It represents the findings at the north end of the quarry during our visit in July 2003. It should not be relied upon by any third party, nor does it relieve any third party the responsibility of carrying out their own project specific tests in their assessment of the stone for use on building projects.

This report is licensed to our client Cadeby Stone Limited to provide an assessment of Cadeby limestone for use as dimension stone. Reproduction of this report for providing third parties with information on the suitability of Cadeby limestone as dimension stone shall only be undertaken in full. Reproduction for other purposes without the written permission of Ove Arup & Partners Limited is prohibited.

Page 1

Ove Arup & Partners Ltd Issue 2 February 2004

Cadeby Stone Limited

2.

Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

BACKGROUND The quarry is located in the village of Cadeby, approximately three miles west Doncaster, South Yorkshire. See Figure 1. Currently, the northern end of the quarry is worked for dimension stone

by CSL.

2.1

Geology According to the 1:50,000 geological map of the area (Barnsley Sheet 87, Solid and Drift edition), the Cadeby stone is part of the Lower Magnesian limestone deposit (of Lower Permian age) that outcrops in a band running approximately in a north-south orientation from Nottingham to Durham.

The Cadeby limestone is recorded as outcropping across the full extent of the quarry. No major faults are indicated at the quarry location. However, north-east to south-west and west-north-west to east-south-east orientated faults (typical of the region) are recorded as running close to the southern and western boundaries of the quarry. See Figure 2.

2.2

Previous uses Historically, magnesian limestone has been used as a building stone in the UK, typically supplying the local market. In the case of Cadeby limestone, it is reported as having been used as a traditional building stone, as well as being a popular stone in the domestic market where it is used internally (e.g. fireplaces, floors) and externally (e.g. split walling stone). More recently, the stone has been used as cladding on larger scale building projects in areas such as York and London. See Figures 3 to 5.

Page 2

Ove Arup & Partners Ltd Issue 2 February 2004

Cadeby Stone Limited

3.

QUARRY

3.1

Location

Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

The total quarry area (including future operations) is approximately 160 hectares. However, at the time of this report the area defined by the faces of the quarry covers only approximately 80 hectares. See Figures 6 and 7.

3.2

Source of dimension stone The blocks of Cadeby limestone are extracted from the northern end of the quarry. The estimated volume of material in this area equates to approximately 5 years reserve to the north of the current face and 30 years reserve to the east of this face based on current production rates. See Figure 8.

The colour of the Cadeby limestone ranges from creamy white to brown. These colours are fairly typical of magnesian limestone, and can be seen on a number of buildings clad with Cadeby limestone in York. From this range, CSL have divided the stone in to three colours, naming it Cadeby White, Cadeby Light Gold and Cadeby Brown limestone.

The overall quarry face is approximately 40m high where clear horizontal bedding planes are visible. Across this face there are two marker bands of grey clay, one at approximately 15m above the current quarry floor level and the other, a thicker band, at approximately 25m above the quarry floor level. From our examination of the quarry face, it would appear that the joint spacing and bed heights in material above the upper clay marker band are too close to allow reasonable size blocks of dimension stone to be extracted. Below this level the joint spacing and bed heights appear more favourable for dimension stone sized block. However, the actual block size will be dependant on joint spacing which cannot be accurately determined at this stage. It is from the first 10m of stone, from the quarry floor level, that CSL are currently extracting blocks of Cadeby White limestone. During the visit the quarry manager informed us that 8 to 15 T blocks were being extracted from the Cadeby White face. See Figures 9, 10 and 11. Cadeby Light Gold and Cadeby Brown is found overlying this.

3.3

Transportation routes At present, the main options for transporting block or finished stone from the quarry is by road or river. The quarry is located within 2 miles of the A1(M) giving vehicles access to the road network. It is also located next to the River Don making it possible to transport block by boat to the Port of Hull, offering links to Europe and Scandinavia.

3.4

Block extraction Block extraction was previously carried out by means of blasting the stone. This method has now changed and explosives are no longer used. Instead the block is removed using an excavator which makes use of the natural planes of weakness in the rock created by beds and joints, to allow removal of the material from the quarry face. This change in method of extracting block should help to increase the volume of usable material.

CSL state that the current extraction of the raw block is reported to be about 250T a week. This is a reasonable rate of extraction for supply of raw material for large scale construction projects.

3.5

Fabrication works A fabrication works is located within the bounds of the quarry site. This contains one primary saw and two secondary saws for slabbing block and cutting stone to size. At present, the size of the

Page 3

Ove Arup & Partners Ltd Issue 2 February 2004

Cadeby Stone Limited

Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

works is limited, but suitable for supplying finished stone for the existing domestic market and smaller scale projects. At present, fabrication for larger scale projects would need to be out sourced to an appropriate sized works. This would be possible as the block could be bought from CSL and taken elsewhere for fabrication.

Page 4

Ove Arup & Partners Ltd Issue 2 February 2004

Cadeby Stone Limited

4.

Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

TECHNICAL PROPERTIES As part of the assessment into the suitability of the Cadeby limestone for cladding and flooring, CSL arranged for samples of the Cadeby White, Light Gold and Brown limestone to be selected and sent to a UKAS accredited laboratory for testing. The testing, carried out in November 2002, has provided information on the technical properties of the stone and is reported as being representative of the stone currently being extracted.

4.1

Test regime The following tests were carried out on specimens taken from each of the Cadeby White, Cadeby Light Gold and Cadeby Brown limestone: Name of test

Test Method

Purpose of test

Petrographic examination

BS EN 12407 : 2000

Determine the composition of the stone

Density & Porosity

BS EN 1936 : 1999

Index test

Water absorption

BS EN 13755 : 2002

Index test

Saturation coefficient & Porosity

BRE Report BR 141 : 1989

Assess durability

Compressive strength

BS EN 1926 : 1999

Assess strength in compression

Flexural strength

pr EN 13161

Assess strength in bending

Freeze thaw

BS EN 12371 : 2001

Assess durability (frost resistance)

Salt crystallisation

BS EN 12370 : 1999

Assess durability (resistance to salt damage)

Abrasion resistance

BS EN 1341 : 2000

Assess durability (resistance to being trafficked).

Flooring/paving specific test.

Slip resistance

Sandberg Internal Procedure TP/F/16

Assess potential for slip.

Flooring/paving specific test.

Page 5

Ove Arup & Partners Ltd Issue 2 February 2004

Cadeby Stone Limited

4.2

Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

Cadeby White - Results and Interpretation As part of the interpretation of the test results, the documents listed below have been referred to.

Name of test

Guidance

Petrographic examination

N/A

Density & Porosity

ASTM C568

Water absorption

ASTM C568

Saturation coefficient & Porosity

BRE Report 141 : 1989 BRE Digest 420 : 1997

Compressive strength

ASTM C568

Flexural strength

BRE Information Paper 7/98 : 1998

Freeze thaw

BS EN 12371 : 2001

Salt crystallisation

BRE Report 141 : 1989

Abrasion resistance

BRE Information Paper 10/00 : 2000

Slip resistance

BRE Information Paper 10/00 : 2000

4.2.1

Petrographic Examination

Based on the results of the petrographic examination carried out on the sample provided, the Cadeby white is described as follows: White to off-white, fine grained LIMESTONE (Dolomite or Dolomitic Limestone). Pale blueish grey spots up to 3mm across were frequently present (possibly manganese oxide).

From the detailed petrographic description, no deleterious materials, that may adversely affect the technical performance of the stone, were identified.

4.2.2

Density & Porosity

The results of the 6 specimens tested in accordance with BS EN 1936 : 1999 are as follows: Apparent Density (kg/m3)

Open Porosity (%)

Range

Mean

Range

Mean

2146 – 2180

2170

17.66 – 18.91

18.05

According to ASTM C568, the mean result of the tests indicates that the Cadeby White can be classified as a medium density limestone. The mean value of the porosity test is normal for a medium density limestone.

Page 6

Ove Arup & Partners Ltd Issue 2 February 2004

Cadeby Stone Limited

4.2.3

Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

Water Absorption

The results of the 6 specimens tested in accordance with BS EN 13755 : 2002 are as follows: Water Absorption (%) Range

Mean

7.03 – 7.45

7.28

According to ASTM C568, the mean result of the test is acceptable for a medium density limestone.

4.2.4

Saturation coefficient & Porosity

The results of the 4 specimens tested in accordance with BRE Report BR141 : 1989 are as follows: Saturation Coefficient

Porosity (%)

Range

Mean

Range

Mean

0.86 – 0.88

0.87

16.29- 16.94

16.84

The mean value of the porosity test is typical for a medium density limestone. However, according to BRE Digest 420, a mean saturation coefficient value greater than 0.85 is indicative of a limestone that may be less durable if used where the “stone is intended to have a longer life or for harsher exposures (such as string courses or copings) or severe environments”. In these instances it may be more appropriate to protect the stone with a flashing or use the Cadeby Light Gold or Cadeby Brown. Any durability assessment of the Cadeby should take into account both the stones position on the building and the weathering to which it will be exposed.

4.2.5

Compressive Strength

This test was carried out on 24 specimens in accordance with BS EN 1926 :1999. 6 specimens each were tested in 4 test conditions as follows: i)

Load applied perpendicular to the bedding (natural bedded) in the dry condition

ii)

Load applied perpendicular to the bedding (natural bedded) in the wet condition

iii)

Load applied parallel to the bedding (face bedded) in the dry condition

iv)

Load applied parallel to the bedding (face bedded) in the wet condition

The results are as follows: Orientation/Condition

Compressive Strength (MPa) Range

Mean

Perpendicular to bedding/Dry

77.74-86.75

81.76

Perpendicular to bedding/Wet

56.19-68.63

62.76

Parallel to bedding/Dry

59.92-91.78

79.20

Parallel to bedding/Wet

34.41-66.34

47.53

According to ASTM C568, the mean values for the test in all conditions are satisfactory for a medium density limestone.

Page 7

Ove Arup & Partners Ltd Issue 2 February 2004

Cadeby Stone Limited

4.2.6

Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

Flexural Strength

This test was carried out on 40 specimens in accordance with pr EN 13161. 6 specimens each were tested in 4 test conditions: v)

Load applied perpendicular to the bedding (natural bedded) in the dry condition

vi)

Load applied perpendicular to the bedding (natural bedded) in the wet condition

vii)

Load applied parallel to the bedding (face bedded) in the dry condition

viii)

Load applied parallel to the bedding (face bedded) in the wet condition

The results are as follows: Orientation/Condition

Flexural Strength (MPa) Range

Mean

Perpendicular to bedding/Dry

4.67 – 13.61

9.17

Perpendicular to bedding/Wet

4.90 – 12.72

8.51

Parallel to bedding/Dry

7.81 – 9.71

8.59

Parallel to bedding/Wet

6.65 – 7.75

7.28

The mean values for the test in all conditions are satisfactory for a medium density limestone.

However, for any cladding or flooring project the flexural strength required should be assessed on a project specific basis, e.g. for external cladding the design flexural strength required should take into account other design specific factors such as the panel length, height and thickness, the proposed fixing arrangement and anticipated wind loads at various locations across a building.

See Section 5 for further discussion.

4.2.7

Freeze Thaw

This test was carried out in accordance with Sandberg Internal Method TP/G/19/1, which is based on BS EN 12371 : 2001 Identification Test (Test B) to 25 freeze and thaw cycles. The results of the 6 specimens are as follows: Visual inspection

:

After 25 cycles the faces and sides of all specimens were classified as ‘0’ (i.e. the specimens were intact and did not display any signs of distress).

Apparent volume

:

After 14 cycles there was no measured loss in volume percentage change in apparent volume. Deterioration is considered to have occurred if the reduction in apparent volume reaches 1%.

Based on the results of the test the Cadeby White appears to be frost resistant.

Page 8

Ove Arup & Partners Ltd Issue 2 February 2004

Cadeby Stone Limited

Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

4.2.8

Salt Crystallisation

The results of the 6 specimens tested in accordance with BS EN 12370 : 1999 are as follows: Average Weight Loss after 15 cycles (%) Range

Mean

4.96 – 19.61

14.1

According to BRE Report 141 : 1989, a limestone with a weight loss of >5 to 15% is given a durability Class C. In general, this indicates that the Cadeby White should be suitable for many uses as an external building stone in inland locations where exposure to salts (e.g. road salts) is fairly limited.

However, the results also indicate that care should be taken where the stone is considered for use as external paving, if it is likely to come into contact with salts. Also, care should be taken when using the stone in exposed coastal locations.

4.2.9

Abrasion Resistance

The results of the 6 specimens tested in accordance with BS EN 1341 : 2000 Annex C (Wide Wheel Abrasion) are as follows: Abrasion Resistance Value (mm) Range

Mean

26.7 – 30.6

29.0

According to the guidance given in BRE IP 10/00 a mean abrasion resistance value between 23 and 30 is indicative a stone suitable for use in a moderately trafficked area (e.g. office buildings).

This guidance given in BRE IP 10/00 does not take into account the cleaning and maintenance regime of a floor.

On this basis the Cadeby White appears to be suitable for use on moderately trafficked floors.

4.2.10

Slip Resistance

This test was carried out on a specimen with a sawn surface in a dry and wet condition, using a pendulum tester with a Four S ‘simulated standard Shoe Sole’ rubber. The results of the test are as follows: Orientation

Slip Resistance Value – Dry Condition Range Mean

Slip Resistance Value – Wet Condition Range Mean

A

67 – 69

68

63 – 64

64

90o to A

66 – 68

67

63 - 64

63

According to guidance given by the UK Slip Resistance Group1 values between 35 and 65 are indicative of a stone with a low potential for slip. Values above 65 have an extremely low potential for slip. Therefore, it would appear that the Cadeby White has a borderline low to extremely low potential for slip, for both the dry and wet condition when a sawn surface is used.

These results are applicable for the Cadeby White with a sawn surface only, if it is to be used with a smoother finish then the test should be repeated with that finish.

1

The measurement of floor slip resistance guidelines recommended by the UK Slip Resistance Group, Issue 2, June 2000 Page 9

Ove Arup & Partners Ltd Issue 2 February 2004

Cadeby Stone Limited

4.3

Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

Cadeby Light Gold - Results and Interpretation As part of the interpretation of the test results, the documents listed in the table in Section 4.2 have been referred to.

4.3.1

Petrographic Examination

Based on the results of the petrographic examination carried out on the sample provided, the Cadeby Light gold is described as follows: Pale yellow, fine grained LIMESTONE (Dolomite or Dolomitic Limestone). Stippled with numerous pale blueish grey spots, (possibly manganese oxide) up to 1mm across.

The presence of deleterious materials that may adversely affect the technical performance of the stone have not been identified.

4.3.2

Density & Porosity

The results of the 6 specimens tested in accordance with BS EN 1936 : 1999 are as follows: Apparent Density (kg/m3)

Open Porosity (%)

Range

Mean

Range

Mean

2145 - 2188

2170

17.04 – 18.51

17.60

According to ASTM C568, the mean result of the tests indicates that the Cadeby Light Gold can be classified as a medium density limestone. The mean value of the porosity test is normal for a medium density limestone.

4.3.3

Water Absorption

The results of the 6 specimens tested in accordance with BS EN 13755 : 2002 are as follows: Water Absorption (%) Range

Mean

6.11 – 6.88

6.54

According to ASTM C568, the mean result of the test is acceptable for a medium density limestone.

4.3.4

Saturation coefficient & Porosity

The results of the 4 specimens tested in accordance with BRE Report BR141 : 1989 are as follows: Saturation Coefficient

Porosity (%)

Range

Mean

Range

Mean

0.77 – 0.78

0.78

17.71 – 18.76

18.15

The mean values for saturation coefficient and porosity are indicative of a durable limestone suitable for external use as plain walling or in locations subject to frequent wetting, such as exposed cills and parapets. Any durability assessment of the Cadeby should take into account both the stones position on the building and the weathering to which it will be exposed.

Page 10

Ove Arup & Partners Ltd Issue 2 February 2004

Cadeby Stone Limited

4.3.5

Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

Compressive Strength

This test was carried out on 24 specimens in accordance with BS EN 1926 :1999. 6 specimens each were tested in 4 test conditions as follows: ix)

Load applied perpendicular to the bedding (natural bedded) in the dry condition

x)

Load applied perpendicular to the bedding (natural bedded) in the wet condition

xi)

Load applied parallel to the bedding (face bedded) in the dry condition

xii)

Load applied parallel to the bedding (face bedded) in the wet condition

The results are as follows: Orientation/Condition

Compressive Strength (MPa) Range

Mean

Perpendicular to bedding/Dry

98.71 - 114.00

105.82

Perpendicular to bedding/Wet

84.36 – 94.28

87.94

Parallel to bedding/Dry

56.84 – 83.36

67.78

Parallel to bedding/Wet

44.17 – 66.85

52.83

According to ASTM C568, the mean values for the test in all conditions are satisfactory for a medium density limestone.

4.3.6

Flexural Strength

This test was carried out on 40 specimens in accordance with pr EN 13161. 6 specimens each were tested in 4 test conditions as follows: xiii)

Load applied perpendicular to the bedding (natural bedded) in the dry condition

xiv)

Load applied perpendicular to the bedding (natural bedded) in the wet condition

xv)

Load applied parallel to the bedding (face bedded) in the dry condition

xvi)

Load applied parallel to the bedding (face bedded) in the wet condition

The results are as follows: Orientation/Condition

Flexural Strength (MPa) Range

Mean

Perpendicular to bedding/Dry

3.81 – 9.65

6.81

Perpendicular to bedding/Wet

3.39 – 9.61

7.49

Parallel to bedding/Dry

3.00 – 9.17

6.31

Parallel to bedding/Wet

3.52 – 7.67

5.82

The mean values for the test in all conditions are satisfactory for a medium density limestone.

However, for any cladding or flooring project the flexural strength required should be assessed on a project specific basis, e.g. for external cladding the design flexural strength required should take into account other design specific factors such as the panel length, height and thickness, the proposed fixing arrangement and anticipated wind loads at various locations across a building.

See Section 5 for further discussion.

Page 11

Ove Arup & Partners Ltd Issue 2 February 2004

Cadeby Stone Limited

4.3.7

Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

Freeze Thaw

This test was carried out in accordance with Sandberg Internal Method TP/G/19/1, which is based on BS EN 12371 : 2001 Identification Test (Test B) to 25 freeze and thaw cycles. The results of the 6 specimens are as follows: Visual inspection

:

After 25 cycles the faces and sides of all specimens were classified as ‘0’ (i.e. the specimens were intact and did not display any signs of distress).

Apparent volume

:

After 14 cycles there was no measured loss in volume.

Deterioration is considered to have occurred if the reduction in apparent volume reaches 1%.

Based on the results of the test the Cadeby Light Gold appears to be frost resistant.

4.3.8

Salt Crystallisation

The results of the 6 specimens tested in accordance with BS EN 12370 : 1999 are as follows: Average Weight Loss after 15 cycles (%) Range

Mean

0.17 – 0.87

0.4

According to BRE Report 141 : 1989, a limestone with a weight loss of <1% is given a durability Class A. In general, this is indicates that the Cadeby Light Gold should be suitable for uses in all external building and paving applications that are likely to come into contact with salts (e.g. road salts or salt in sea air).

4.3.9

Abrasion Resistance

The results of the 6 specimens tested in accordance with BS EN 1341 :2000 Annex C (Wide Wheel Abrasion) are as follows: Abrasion Resistance Value (mm) Range

Mean

26.0 – 28.2

26.7

According to the guidance given in BRE IP 10/00 a mean abrasion resistance value between 23 and 30 is indicative a stone suitable for use in a moderately trafficked area (e.g. office buildings).

This guidance given in BRE IP 10/00 does not take into account the cleaning and maintenance regime of a floor.

On this basis the Cadeby Light Gold appears suitable for use on moderately trafficked floors.

Page 12

Ove Arup & Partners Ltd Issue 2 February 2004

Cadeby Stone Limited

Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

4.3.10

Slip Resistance

This test was carried out on a specimen with a sawn surface in a dry and wet condition, using a pendulum tester with a Four S ‘simulated standard Shoe Sole’ rubber.

Orientation

Slip Resistance Value – Dry Condition Range Mean

Slip Resistance Value – Wet Condition Range Mean

A

64 - 65

65

61 - 63

62

90o to A

69 - 70

69

65 - 66

65

According to guidance given by the UK Slip Resistance Group2 values between 35 and 65 are indicative of a stone that has a low potential for slip. Values above 65 have an extremely low potential for slip. Therefore, it would appear that the Cadeby Light Gold has a borderline low to extremely low potential for slip, for both the dry and wet condition, when a sawn surface is used.

These results are applicable for the Cadeby Light Gold with a sawn surface only, if it is to be used with a smoother finish then the test should be repeated with that finish.

2

The measurement of floor slip resistance guidelines recommended by the UK Slip Resistance Group, Issue 2, June 2000 Page 13

Ove Arup & Partners Ltd Issue 2 February 2004

Cadeby Stone Limited

4.4

Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

Cadeby Brown - Results and Interpretation As part of the interpretation of the test results, the documents listed in the table in Section 4.2 have been referred to.

4.4.1

Petrographic Examination

Based on the results of the petrographic examination of the sample provided, the Cadeby Brown is described as follows: Dark, fine area: Pale brown, beige fine to very fine grained LIMESTONE (Dolomite or Dolomitic Limestone).

Light, coarse area: Pale brown, beige fine grained LIMESTONE (Dolomite or Dolomitic limestone). Allochems (i.e. ooids, peloids and bioclasts) up to 10mm across and commonly less than 4mm in size, imparted a coarse appearance to the stone.

The presence of deleterious materials that may adversely affect the technical performance of the stone have not been identified.

4.4.2

Density & Porosity

The results of the 6 specimens tested in accordance with BS EN 1936 : 1999 are as follows: Apparent Density (kg/m3)

Open Porosity (%)

Range

Mean

Range

Mean

2050 - 2145

2100

18.94 – 22.55

20.57

According to ASTM C568, the mean result of the tests indicates that the Cadeby Brown can be classified as a borderline low to medium density limestone. The mean value of the porosity test is slightly higher than would be expected for a medium density limestone3.

4.4.3

Water Absorption

The results of the 6 specimens tested in accordance with BS EN 13755 : 2002 are as follows: Water Absorption (%) Range

Mean

7.11 – 8.58

7.89

The mean result of the test is acceptable for a medium density limestone.

4.4.4

Saturation coefficient & Porosity

The results of the 4 specimens tested in accordance with BRE Report BR141 : 1989 are as follows: Saturation Coefficient

Porosity (%)

Range

Mean

Range

Mean

0.58 – 0.61

0.60

11.33 – 11.75

11.52

3

Note: The porosity value is quite different to that obtained from the saturation coefficient and porosity testing. It is possible that the specimen tested was more open textured/porous than that used for the saturation coefficient testing.

Page 14

Ove Arup & Partners Ltd Issue 2 February 2004

Cadeby Stone Limited

Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

The mean values for saturation coefficient and porosity are indicative of a durable limestone suitable for external use as plain walling or in locations subject to frequent wetting, such as exposed cills and parapets.

4.4.5

Compressive Strength

This test was carried out on 24 specimens in accordance with BS EN 1926 :1999. 6 specimens each were tested in 4 test conditions as follows: xvii)

Load applied perpendicular to the bedding (natural bedded) in the dry condition

xviii)

Load applied perpendicular to the bedding (natural bedded) in the wet condition

xix)

Load applied parallel to the bedding (face bedded) in the dry condition

xx)

Load applied parallel to the bedding (face bedded) in the wet condition

The results are as follows: Orientation/Condition

Compressive Strength (MPa) Range

Mean

Perpendicular to bedding/Dry

90.53 – 112.37

103.04

Perpendicular to bedding/Wet

87.85 – 101.66

65.52

Parallel to bedding/Dry

42.62 – 81.77

63.32

Parallel to bedding/Wet

42.99 – 53.81

47.60

According to ASTM C568, the mean values for the test in all conditions are satisfactory for a medium density limestone.

4.4.6

Flexural Strength

This test was carried out on 40 specimens in accordance with pr EN 13161. 6 specimens each were tested in 4 test orientations: xxi)

Load applied perpendicular to the bedding (natural bedded) in the dry condition

xxii)

Load applied perpendicular to the bedding (natural bedded) in the wet condition

xxiii)

Load applied parallel to the bedding (face bedded) in the dry condition

xxiv)

Load applied parallel to the bedding (face bedded) in the wet condition

The results are as follows: Orientation/Condition

Flexural Strength (MPa) Range

Mean

Perpendicular to bedding/Dry

6.58 – 11.37

7.84

Perpendicular to bedding/Wet

6.09 – 11.19

8.75

Parallel to bedding/Dry

5.71 – 11.86

8.35

Parallel to bedding/Wet

3.53 – 10.68

6.55

The mean values for the test in all conditions are satisfactory for a medium density limestone.

However, for any cladding or flooring project the flexural strength required should be assessed on a project specific basis, e.g. for external cladding the design flexural strength required should take into account other design specific factors such as the panel length, height and thickness, the

Page 15

Ove Arup & Partners Ltd Issue 2 February 2004

Cadeby Stone Limited

Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

proposed fixing arrangement and anticipated wind loads at various locations across a building.

See Section 5 for further discussion.

4.4.7

Freeze Thaw

This test was carried out in accordance with Sandberg Internal Method TP/G/19/1, which is based on BS EN 12371 : 2001 Identification Test (Test B) to 25 freeze and thaw cycles. The results of the 6 specimens are as follows: Visual inspection

:

After 25 cycles the faces and sides of all specimens were classified as ‘0’ (i.e. the specimens were intact and did not display any signs of distress).

Apparent volume

:

After 14 cycles there was no measured loss in volume.

Deterioration is considered to have occurred if the reduction in apparent volume reaches 1%.

Based on the results of the test the Cadeby Brown appears to be frost resistant.

4.4.8

Salt Crystallisation

The results of the 6 specimens tested in accordance with BS EN 12370 : 1999 are as follows: Average Weight Loss after 15 cycles (%) Range

Mean

2.16 – 5.72

3.3

According to BRE Report 141 : 1989, a limestone with a weight loss of 1 to 5% is given a durability class B. In general, this indicates that the Cadeby Brown should be suitable for use as an external building stone at exposed coastal and inland locations, where the possibility of exposure to salts (e.g. road salts or salts in the sea air) may exist. However, the results also indicate that the stone should not be used as external paving, if the material is likely to come into contact with salts.

4.4.9

Abrasion Resistance

The results of the 6 specimens tested in accordance with BS EN 1341 :2000 Annex C (Wide Wheel Abrasion) are as follows: Abrasion Resistance Value (mm) Range

Mean

21.7 – 26.2

23.3

According to the guidance given in BRE IP 10/00 a mean abrasion resistance value between 23 and 30 is indicative a stone suitable for use in a moderately trafficked area (e.g. office buildings).

A value less than 23 is indicative of a stone suitable for use in highly trafficked areas (e.g. shopping malls). The guidance given in BRE IP 10/00 does not take into account the cleaning and maintenance regime of a floor.

On this basis the Cadeby Brown appears suitable for use on moderately trafficked floors and possibly some more highly trafficked areas.

Page 16

Ove Arup & Partners Ltd Issue 2 February 2004

Cadeby Stone Limited

Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

4.4.10

Slip Resistance

This test was carried out on a specimen with a sawn surface in a dry and wet condition, using a pendulum tester with a Four S ‘simulated standard Shoe Sole’ rubber.

Orientation

Slip Resistance Value – Dry Condition Range Mean

Slip Resistance Value – Wet Condition Range Mean

A

68 - 70

69

64 - 65

64

90o to A

69 - 70

70

64 - 65

65

According to guidance given by the UK Slip Resistance Group4 values between 35 and 65 are indicative of a stone that has a low potential for slip. Values above 65 have an extremely low potential for slip. Therefore, it would appear that the Cadeby Brown has a borderline low to extremely low potential for slip, for both the dry and wet condition, when a sawn surface is used.

These results are applicable for the Cadeby Brown with a sawn surface only, if it is to be used with a smoother finish then the test should be repeated with that finish.

4

The measurement of floor slip resistance guidelines recommended by the UK Slip Resistance Group, Issue 2, June 2000 Page 17

Ove Arup & Partners Ltd Issue 2 February 2004

Cadeby Stone Limited

5.

Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

APPROPRIATE THICKNESS OF STONE FOR CLADDING DESIGN Traditionally British limestone has been used at 75mm thick when used as hand fixed stone or at 50mm thick when used as stone faced precast concrete. These thicknesses comply with the guidelines given in BS8292 : 1994. However, this standard also allows a reduction in thickness to be made if supported by a structural calculation.

Based on the flexural strength test data provided, the mean for the Cadeby White, Cadeby Light Gold and Cadeby Brown are as follows: Cadeby White – Flexural Strength (MPa)

Cadeby Light Gold – Flexural Strength (MPa)

Cadeby Brown – Flexural Strength (MPa)

Mean

Mean

Mean

9.2

6.8

7.7

8.5

7.5

8.7

8.6

6.3

8.3

7.3

5.8

6.5

Perpendicular/ Dry Condition Perpendicular/ Wet Condition Parallel/ Dry Condition Parallel/ Wet Condition

For the purpose of this report AFE has undertaken a structural analysis of the stone to determine the acceptable thickness of a panel broadly in accordance with BRE IP 7/98. Our analysis was based on a the following assumptions: - a stone panel 1m by 0.7m high.

- support/restraint by four fixings.

- a wind pressure of 1.5 KPa. - a factor of safety of 6.

The outcome of this analysis, based on the mean flexural strength values and assumptions given above, indicates that each of the Cadeby White, Cadeby Light Gold and Cadeby Brown is strong enough to be used at 40mm thick.

It is important to remember that the above is an example based on the test data provided and the assumptions on wind loading and panel support given above. It should not be relied on, or used, by any third party as part of their stone cladding design. For each project, the design should involve using project specific parameters such as anticipated loadings, fixing arrangement, and strength of stone should be determined.

Page 18

Ove Arup & Partners Ltd Issue 2 February 2004

Cadeby Stone Limited

6.

SUMMARY

6.1

General

Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

The Cadeby limestone is a magnesian limestone with colour ranging from creamy white to brown. It is understood that the creamy white coloured limestone (Cadeby White) is found in the lower beds visible in the quarry, and the honey to buff coloured limestone (Cadeby Light Gold and Cadeby Brown) is found in the overlying beds.

At present, the bed heights and joint spacing in the lower beds are of sufficient size to allow blocks of a commercially attractive size to be extracted, with the exception of the uppermost beds that appear too closely jointed to produce a reasonable sized block. Based on the block stockpiled in the yard, it would appear that reasonable sized blocks in each of the three colour can be extracted from the quarry.

We are informed that there is approximately 5 years of reserves available to the north of the face currently being worked, and there is approximately 30 years reserve to the east of this face, indicating an adequate future supply of the stone.

6.2

Technical Properties In general, the Cadeby limestone currently being extracted is suitable for use as dimension stone.

Use of the Cadeby limestone as walling Current test data suggests that all three types of Cadeby limestone should be suitable for use as external cladding at 40mm thick, this is based on the assumptions given in Section 5 above. It should be noted that, as with all stones, the thickness selection and fixing design requires checking on a case-by-case basis as it is dependant on several variable factors.

Use of the Cadeby limestone as external paving/internal flooring Based on the recent test data, each of the three colours of Cadeby appear to be suitable for use as internal flooring and external paving in moderately trafficked areas, such as an office. However, based on the salt crystallisation test results, it would appear that only the Cadeby Brown should be used as external paving, if the material is likely to come into contact with salts. Each of the stones are noted to be slip resistant when wet or dry, providing the stone has a sawn surface finish Each of the stones are frost resistant.

Page 19

Ove Arup & Partners Ltd Issue 2 February 2004

Cadeby Stone Limited

Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

Figures

Page 20

Ove Arup & Partners Ltd Issue 2 February 2004

Cadeby Stone Limited

Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

Figure 1. Location of the Cadeby Magnesian Limestone quarry

Š Crown Copyright

Page 21

Ove Arup & Partners Ltd Issue 2 February 2004

Cadeby Stone Limited

Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

Figure 2. Map showing the surface geology of Cadeby and the surrounding area.

Extract taken from 1:50,000 geological map â&#x20AC;&#x201C; Barnsley Sheet 87, solid and drift Š Crown Copyright, NERC Copyright

Page 22

Ove Arup & Partners Ltd Issue 2 February 2004

Cadeby Stone Limited

Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

Figures 3. Norwich Union building, York.

Note: This building is clad using the three colours of Cadeby limestone available.

Page 23

Ove Arup & Partners Ltd Issue 2 February 2004

Cadeby Stone Limited

Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

Figure 4. Travelodge, York

Note: This building is clad using the three colours of Cadeby limestone available.

Page 24

Ove Arup & Partners Ltd Issue 2 February 2004

Cadeby Stone Limited

Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

Figure 5. Residential building, York

Note: This building is clad using the three colours of Cadeby limestone available.

Page 25

Ove Arup & Partners Ltd Issue 2 February 2004

Cadeby Stone Limited

Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

Figure 6. Aerial view of the Cadeby limestone quarry

Page 26

Ove Arup & Partners Ltd Issue 2 February 2004

Cadeby Stone Limited

Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

Figure 7. Plan of quarry showing current extent of extraction

Figure 8. Plan of quarry showing areas/reserves available for extraction

Page 27

Ove Arup & Partners Ltd Issue 2 February 2004

Cadeby Stone Limited

Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

Figure 9. Photo of the north east face of the quarry

Note: The NE face of the quarry represents the area being worked for Cadeby White during the visit Page 28

Ove Arup & Partners Ltd Issue 2 February 2004

Cadeby Stone Limited

Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

Figure 10. Photo showing beds of Cadeby White limestone

Page 29

Ove Arup & Partners Ltd Issue 2 February 2004

Cadeby Stone Limited

Cadeby limestone Assessment of Cadeby limestone for use as dimension stone

Figure 11. Photo showing typical block size available in Cadeby White

Page 30

Ove Arup & Partners Ltd Issue 2 February 2004