Claverton Pumping Station at Claverton, which was built of Bath Stone in about 1810, pumps water from the River Avon to the Kennet and Avon Canal, using power from the flow of the River Avon. The material has also been used widely outside Bath itself. Bath stone was taken from the Bath Oolite Member and the Combe Down Member of the Chalfield Oolite Formation, part of the Great Oolite Group. They frequently contain minute fragments of shell or rock, and sometimes even decayed skeletons of marine life. Rocks composed of ooids larger than 2 mm are called pisolites. Strictly, oolites consist of ooids of diameter 0.25–2 mm. That name derives from the Hellenic word òoion for egg. Under the microscope, these grains or ooliths ( egg stones) are sedimentary rock formed from ooids: spherical grains composed of concentric layers. Layers of marine sediment were deposited, and individual spherical grains were coated with lime as they rolled around the sea bed, forming the Bathonian Series of rocks. Some quarries are still in use, but the majority have been converted to other purposes or are being filled in.īath Stone is an oolitic limestone comprising granular fragments of calcium carbonate laid down during the Jurassic Period (195 to 135 million years ago) when the region that is now Bath was under a shallow sea. An important feature of Bath Stone is that it is a ' freestone', so-called because it can be sawn or 'squared up' in any direction, unlike other rocks such as slate, which form distinct layers.īath Stone has been used extensively as a building material throughout southern England, for churches, houses, and public buildings such as railway stations. Its honey colouring gives the World Heritage City of Bath, England its distinctive appearance. Originally obtained from the Combe Down and Bathampton Down Mines under Combe Down, Somerset, England. The style and Bath stone used are typical of much of the city.īath Stone is an oolitic limestone comprising granular fragments of calcium carbonate. In agreement with previous work on limestone inelastic compaction, the mechanical contrast of allochemical components with respect to cement conditioned the spatial distribution of the microfractures.Great Pulteney Street, Bath, looking West towards Pulteney Bridge. Microfracturing initiated at grain boundaries, where stress concentrations were higher. The highest density of microcracks and twinned grains were observed in samples subjected to longer exposure periods of time, suggesting that the exposure time constitutes an essential factor in rock softening. Micro-fracturing, twinning, and rigid body rotation were the main mechanisms of the deformations observed. While the change in effective porosity increased and the Young’s modulus decreased with exposure time, the peak strength decreased with exposure time and decreasing pH. Results show that both, acid concentration and exposure period have a significant influence not only in changes of effective porosity, Young’s modulus and peak strength, but also in the development of stress-induced microstructures. Uniaxial and triaxial compression tests were conducted on fresh and chemically weathered oolitic limestone samples submerged in acidic solutions with pH5 and pH3 values for 30 and 50 days each. * Corresponding author: understanding of the variation of mechanical properties and microstructural changes of rocks due to chemical weathering is critical for prospection, extraction and storage of energy resources in the subsurface. Niazi 2, Colton Amstutz 2 and Zachary Brown 2ġ Construction Engineering Technology, School of Polytechnic, Purdue University Fort Wayne, 2101 East Coliseum Blvd., Fort Wayne, IN 46805, USAĢ Department of Civil and Mechanical Engineering, Purdue University Fort Wayne, 2101 East Coliseum Blvd., Fort Wayne, IN 46805, USA
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