Original Cerchar abrasiveness index tester (OCAI 70) – ASTM D The OCAI accurately determines the rock abrasivity index (CAI) employed for the. ASTM D Standard Test Method for Laboratory Determination of Abrasiveness of Rock Using the CERCHAR Method Link. Two standards exist for this test method: the French. standard AFNOR NF P () and ASTM. D (). The test is widely.

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However, there are situations where stylus with different Rockwell Hardness can be used Therefore, this test method includes discussions on stylus with different Rockwell Hardness. Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard.

Both devices include dd7625 following main parts: Rock abrasiveness governs the performance of disc cutters, the rate of its replacement and therefore subsequent tunnel costs. The rock sample is placed in the equipment and firmly clamped using a rigid vice.

ASTM D | Testing Services | Cerchar Abrasivity Index (CAI)

It allows to determine an index called CERCHAR Abrasicity Index CAI for the qstm abrasivity which can be used for evaluate the wear of excavation equipment in different application such as mining, tunnelling and drilling. The abrasivity of rock and soil is a factor of significant importance for excavation in tunnelling, underground construction, mining or quarrying.

Abraison can be defined as wearing or tearing away of particles and material from the solid surface. Work Item s – proposed revisions of this standard. It should have a diamater of at least 6 mm and the length should be such at the visibile part of th epin is at least 15 mm. The Cerchar abrasiveness index. Users of these practices are cautioned that compliance with Practice D does not in itself assure reliable results.

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The testing principle is based on a steel pin with defined geometry and hardness that is scratches the surface of a rough rock sample over a distance of 10 mm under static load of 70 N.

In heterogeneous rock types such as conglomerates, coarse grained granite or schistose rock, suitable fresh test surfaces are not achieved by mechanical breakage using a hammer. CAI is used to assess the abrasiveness of rock for mechanical excavation. There are two equipment design to run the test:. The main difference between the two methods is in the duration of the test.

Advances in methods of underground excavation, in particular the use of the tunnel boring machine TBMnecessitates knowledge of rock abrasiveness. Can you edit this page?

The CAI values obtained for both testing velocities 1 are estimated to be equal. Pricing information and quote request on Geotechgate.

Link to Active This link will always route to the current Active version of the standard. Cerchar Abrasivity test equipment The testing principle is based on a steel pin ast defined geometry and hardness that is scratches the surface of a rough rock sample over a distance of 10 mm under static load of 70 N.

Free quote for buying vane shear test equipment: Rock abrasiveness testing for tunnelling.

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The test method consists of measuring the wear on d76255 tip of steel stylus with a cone shape and known Rockwell Hardness, caused by scratching against a freshly broken or saw cut rock surface for a prescribed 10 mm distance using one of the two test apparatus. Agencies that meet the criteria of Practice D are generally considered capable of competent and objective testing and sampling. After the test, th epin is carefully removed and the tip flat wear is measured.

Reliable results depend on many factors; Practice D provides a means of evaluating some of those factors. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Laboratory Tests on Rock – List of Tests – Tonon USA

Copyright – Geotechdata. The Cerchar- Abrasivity-Index CAI is then calculated from the measured diameter of the resulting wear flat on the pin: Abrasiveness expresses a behavioral characteristic of rock rather than a fundamental physical or d77625 property. While, in the E7625 design, the rock sample moves under a stationary pin. CAI tests were originally carried out on natural broken surfaces. No other units of measurement are included in this standard.

The device is rigid and also fixed to avoid any lateral movement.

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