New Independent Whitbed technical data

A. Petrography

The stone is a strong, moderately hard, light buff, medium grained with occasionally coarse to very course grains, fresh, massively bedded, sometimes fossiliferous, variably intraclastic and/or peloidal, microcrystalline to microsparry Limestone (intramicrite to pelmicrosparite).

B. Strength

1. Compression - BS EN 1926
Average: 49.29 Mpa from 24 tests
Lowest Expected Value 21.25 Mpa
Highest Expected Value 98.84 Mpa

2. Flexural Strength - BS EN 13161
Average: 5.59 Mpa from 193 tests
Lowest Expected Value 3.37 Mpa
Highest Expected Value 8.58 Mpa

C. Durability

1. Water Absorbtion
Average: 5.62% from 149 tests
Lowest Expected Value 4.08%
Highest Expected Value 7.47%

2. Density
Average: 2,256 kg/m³ from 173 tests
Lowest Expected Value 2152 kg/m³
Highest Expected Value 2363 kg/m³

3. Porosity
Average: 16.68% from 149 tests
Lowest Expected Value 13.22%
Highest Expected Value 20.66%

4. Saturation Coefficient
Average: 0.75 from 149 tests
Lowest Expected Value 0.69
Highest Expected Value 0.82

5. Salt Crystallisation

D. Abrasion & Slip Resistance

1. Abrasion Resistance – EN14157 Actual Range: 23.9 to 26.2*
2. Slip Resistance – TRRL Pendulum Test
Grit 60 (External Paving)
Wet: 44*
Dry: 63*

* - Testing carried out on geologically similar stone Bowers Basebed

Internal Flooring
New Independent Whitbed is suitable for all flooring applications up to semi-intensive use such as shops and offices with estimated visitor numbers of 5,000,000 with a service life without significant wear of 20 years. The slip resistance results of over 40 demonstrate that the stone will be safe in all applications.

Technical Summary

Prepared by: Mr B Hunt of IBIS Ltd

New Independent Whitbed was found to be medium density limestone and as such passed the criteria given in ASTM C568 for water absorption and compressive strength. Both the saturation coefficient and the microporosity together might be considered to indicate a stone that could be frost susceptible but this was not confirmed by the freeze-thaw testing, which did not induce any form of breakdown. Further assurance was obtained from the salt crystallisation testing that produced “B” classification suggesting a good resistance to salt attack. The findings of these physical tests seem to concur with the various findings of the petrographic examination and some of the results may be explained better by considering the rock fabric. The stone was found to comprise a range of fabrics of a form that closely resembled the Basebed at the base of the sequence being investigated. The bulk of the New Independent Whitbed exhibited carbonate grains that were both spherical and ovate, these being intraclasts and/or peloids, supported by micrite and only slightly coarser mircosparry calcite (microsparite). It is possible that the various fossils indicate the presence of crypotocrystalline silica helping to hold the stone together, resisting the various potential weathering mechanisms. BRE Report 141 suggests that the stone may be suitable for most uses, including where exposure conditions are to be more severe for example high concentrations of sulfur-dioxide or severe frosts, or where a long life is required (for example >50 years). The preliminary findings suggest that this stone would be suitable for a wide variety of uses and should offer good resistance to expected weathering effects, as demonstrated by the Salt Crystallisation and Frost test results. Although these results are significantly better than Basebed results, we intend to suggest that the stone is used as if it was a Basebed as it lies directly above this stone in the Quarry.

The similarity to Basebed in physical characteristics and performance would suggest that the stone is likely to weather at a rate of between 3mm and 4mm per 100 years but it could be greater in severe exposures

Revision 5 DATE @ 22/09/2006