Dukes Gritstone - Dukes Sandstone Moulded Corbel Stone

Dukes Specification
The quarry is near the town of Whatstandwell in Derbyshire. The quarry has been producing stone since the early part of the 19th century and it has been used in buildings since at least 1825
Petrography
Dukes Gritstone is a Millstone Grit of Carboniferous age. It is a medium-grained stone, pink/lilac in colour with iron, black and buff markings. The average block size is 1400mm x 900mm 700mm.
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. Carboniferous Sandstones are traditionally acknowledged as generally being a very durable building and paving stone and have been used extensively in many towns and cities in the UK. Dukes Gritstone appears to be a durable stone that is not effected by acid rain or air pollution and like most sandstones it is expected have good frost resistance. The compressive strength of the stone is typical of the range for sandstones and is comparable with the stronger UK limestones.
Overall, Dukes Gritstone should be suitable for use in most aspects of load bearing masonry and cladding.
Test Results of Dukes Gritstone
Safety in Use
Slip Resistance (Note 1)
Not determined
Values > 40 are considered safe.
Abrasion Resistance (Note 1)
Not determined
Values <23.0 are considered suitable for use in heavily trafficked areas
Strength under load
1) Compression(Note 2)
74.9 MPa
Loaded perpendicular to the bedding plane ambient humidity
1) Compression(Note 5)
39 – 50 MPa
Dry. Loaded perpendicular to the bedding
2) Bending (Note 1)
8.7 MPa
Loaded perpendicular to the bedding plane ambient humidity
4.8 MPa
Loaded parallel to the bedding plane ambient humidity
Porosity and Water Absorption
1) Porosity (Note 3)
14.11%
2) Saturation Coefficient (Note 3)
0.67
3) Water Absorption
4.18 % (by wt)
4) Bulk specific gravity
2269kg/m3
Resistance to Frost
Freeze/Thaw Test (Note 1)
Not determined
Resistance to Salt
Sodium Sulphate Crystallisation Test (Note 3)
3.13% Mean wt loss
Resistance to Acidity
Acid Immersion Test(Note 4)
Pass
All samples passed the test with no splitting or delamination