Limestone

Broadcroft Basebed Portland Limestone

Petrography Description (EN 12407:2001)

The stone is an open textured oolitic limestone from the Portlandian formation (Jurassic). The stone is formed from micrite (fine-grained calcium carbonate) ooids with a small quantity of micrite occurring as matrix. The shell fragments are elongated to rounded and are typically about 4 mm across. The stone generally appears to be moderately compacted although the degree of compaction is variable. Most of the areas exhibit a fairly high intergranular porosity with interlinking of adjacent pores. In some areas ooids are fused or are surrounded by a sparse carbonate matrix.

Portland - Broadcroft Basebed

Strength Under Load
Compression	95.5MPa	Loaded perpendicular to the bedding - ambient humidity
	63 - 114 MPa	Range of individual samples
Bending	10.0MPa	Modulus of rupture. Loaded parallel to the bedding - ambient humidity
	7.5 – 12.4 MPa	Range of individual samples
Porosity and Water Absorption
Open Porosity	14.2%
	12.2 – 15.9 %	Range of individual samples
Saturation Coefficient	nd
Water Absorption	nd
Bulk specific gravity	2320 kg/m³
	2273 - 2372 kg/m³	Range of individual samples
Microporosity	80.8% of total porosity
	(= 11.5% of 62.1 - 93.2%)	Range of individual samples
Resistance to Frost
Freeze/Thaw Test	Not determined
Resistance to Salt
Sodium Sulphate Crystallisation Test	Mean: 14.68% wt loss
	0.0 + 26.7% wt loss	Range of individual samples

Overall, should be suitable for use in most aspects of construction including flooring, paving, load bearing masonry and cladding including areas where a long service life is needed or where high salt concentrations are expected.

Tests were carried out at BRE in 1997. N.D. = not determined

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