http://www.erocks.co.uk All About Rocks Fri, 03 Feb 2006 19:13:49 +0000 http://backend.userland.com/rss092 en This sample is a fine-grained limestone that consists predominantly of calcite, with a high volume of allochems in the form of various types of bioclasts. Minor coarser-grained calcite and narrow quartz veinlets also traverse this sample. 4.1.1 Macroscopic Features This sample is a fine-grained, pale grey sedimentary rock that is competent (flexed ... http://www.erocks.co.uk/39/41-sample-1-dh-dove-holes/ Samples were examined macroscopically and then a diamond saw was used to section each sample, after which representative samples were used in the preparation of a thin and a polished section. Thin sections were studied using transmitted light microscopy and individual phases within the sample were identified by their optical ... http://www.erocks.co.uk/38/4sample-mineralogy/ A lump sample (14-10mm) is mounted in resin and pushed against a rotating lap for a period of 500 revolutions with a force of 2kg. The percentage of the original sample weight is the AAV. This test gives an insight into mineral cleavage behaviour and intergranular bond strengths. http://www.erocks.co.uk/37/3234aggregate-abrasion-value-aav/ This test is a variation of the ACV where a load specific to the force required to produce 10% fines is investigated where fines are -2360m. The standard range into which the undersize should fall is 7.5% to 12.5%. The force to produce 10% fines is given by:- Where x if ... http://www.erocks.co.uk/36/3233ten-per-cent-fines/ A sample of 2 kg is subjected to a continuous compressive force with a total load of 400kN. The rate of loading is 40kN per minute. As with the AIV the percentage passing 2360m is calculated. With both the AIV and ACV a lower value indicates a “stronger” rock. http://www.erocks.co.uk/35/3232aggregate-crushing-value-acv/ The AIV was incorporated into the British Standards in 1955 as a measure of crushed rock strength. A sample of lumps (14-10mm) is impacted with a piston fifteen times and the product is sieved using a 2360m aperture. The percentage material passing denotes the AIV. The test is then repeated ... http://www.erocks.co.uk/34/3231aggregate-impact-value-aiv/ The British aggregate industry has a set of standard tests that are used to characterise the physical properties of aggregate products. http://www.erocks.co.uk/33/323aggregate-industry-tests/ This technique was also adapted from the ceramics and hard metals industry by Middlemiss and King [1994]. A range of parameters can be obtained from this procedure including fracture toughness, crack length, crack density and extent of cracking. The procedure involves making an indentation into the test piece with a ... http://www.erocks.co.uk/32/3225indentation-fracture-measurement/ This method is limited to very soft or very hard rocks [ISRM Brown (Ed) 1981]. The principle of the test is the determination of the amount of energy absorbed into a rock when impacted upon by a set amount of energy (0.74Nm). The orientation of the hammer is critical because ... http://www.erocks.co.uk/31/3224schmidt-hammer/ This device has been developed at the Utah Comminution Centre [Bourgeois 1992] and has proved to be very successful in recording impact fractures of particulate material. It allows the generation of force time histories when a particle is subjected to an impact. Dropping a steel ball of known mass and ... http://www.erocks.co.uk/30/3223ultra-fast-load-cell/