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Technical Data Sheet
Red St.Bees Sandstone Birkhams
Quarry, St.Bees, Cumbria Silver Street, Crosby
Ravensworth, Cumbria, CA10 3JA Contact : Cumbria Stone Quarries Ltd Tel.
01931 715 227 Fax. 01931 715 367 Email: cumbria@thestancliffegroup.co.uk Website
: http://www.thestancliffegroup.co.uk Grid
reference : NX 955 154
Compiled September 1997 -
updated March 2000
This data sheet was compiled by the Building Research
Establishment (BRE). Where possible, data collected in earlier surveys has been
used to help interpret the test results. The data sheet was compiled in July
1997 using the results of tests carried out to the proposed European Standards.
It was up dated in March 2000. The work was carried out by BRE as part of a
Partners in Technology Programme funded by the Department of the Environment,
Transport and the Regions and Cumbria Stone Quarries Ltd and does not represent
an endorsement of the stone by BRE.
General
The quarry is a cliff side quarry on the coast at Salton Bay,
St Bees Head south of Whitehaven, Cumbria. The quarry and the surrounding area
has been worked since medieval times with materials being shipped by sea - some
to America in the 18th and 19th centuries. The present owners have operated
the quarry since 1981 and there are good reserves of stone.
There is a 3 m overburden with a working face of approximately 20 m. Maximum
block sizes are of the order of 1.25 x 3 x 3 m in size; 1m on bed.
Petrography
Red St.Bees is from the New Red Sandstone of Triassic age. It
is a fine-grained stone, dull red in colour. There are up to 3m of overburden
and the depth of the present face is 22.5m. It is thought that the stone extends
right down to sea level, a depth of 90m. Stone is available, in good lengths and
widths, at depths of 1m on bed.
Expected Durability
and Performance
It is important that the results from the individual tests
are not viewed in isolation. They should be considered together and compared to
the performance of the stone in existing buildings and other uses. Sandstones
from the New Red Sandstone have been used extensively in many towns and cities
in the UK. Red St.Bees sandstone appears to be a less durable stone than some
similar stones (eg Plumpton Red Lazonby) and the test results suggest that
although it may be resistant to air pollution, it is susceptible to weathering
in very salty environments. Earlier test results showed it to have limited
resistance to acidic pollution but the latest samples tested (1999) passed the
test suggesting that the current material has better resistance to acidity.
Based on the limited data available for the interpretation of the frost tests it
seems that the Red St.Bees is typical for a sandstone. There is no loss of
strength as a result of the frost cycles no spalling of the surface or other
loss of material. The compressive strength of the stone is typical of the range
for good sandstones. The abrasion resistance is towards the lower end of the
range and the stone is probably unsuitable for use in heavily trafficked areas.
Overall, Red St Bees should be
suitable for use as load bearing masonry and cladding. Special consideration is
required for areas where there are high salt concentrations and a long service
life is required. The stone has been used for minor
paving applications.
Test Results
- Birkham Red St.Bees
Safety
in Use |
Slip Resistance (Note 1) |
Wet: 75- 85
|
Values > 40 are considered
safe. |
Abrasion Resistance
(Note 1) |
30.6 - 33.4
|
Values <23.0 are considered
suitable for use in heavily trafficked
areas |
Strength
under load |
1) Compression(Note 2) |
78.6 - 100.1 MPa
|
Loaded perpendicular to the
bedding plane ambient humidity |
2) Bending (Note 1) |
8.7 - 9.4
MPa
|
Loaded perpendicular to the
bedding plane ambient humidity |
|
7.9 MPa
|
Loaded parallel to the
bedding plane ambient humidity |
Porosity
and Water Absorption |
1) Porosity (Note 3) |
18.4 - 19.8%
|
|
2) Saturation Coefficient (Note 3) |
0.66
|
|
3) Water Absorption |
5.6 - 6.2% (by wt)
|
|
4) Bulk specific gravity |
2136-2179kg/m3
|
|
Resistance to Frost |
Flexural strength
after Freeze/Thaw Test (Note 1) |
12.8 MPa
|
Loaded perpendicular to the bedding ambient
humidity |
Resistance
to Salt |
Sodium Sulphate Crystallisation Test
(Note 3) |
6.2% Mean wt loss
|
|
Sodium Sulphate Crystallisation Test
(Note 14) (saturated) |
63-100% Mean wt loss
|
|
Resistance to Acidity |
Acid Immersion Test(Note 4) |
Fail (1997) Pass (1999)
|
|
(Test methods Note 1 = prEn1341, Note 2 = prEN 1342,
Note 3 = prEn 1341 /BRE 141, Note 4 = BRE 141)
All tests were carried out at BRE between July and
September 1996 or in 1999)
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