BS EN 12697-32 pdf free download

BS EN 12697-32-2019 pdf free download.Bituminous mixtures – Test methods Part 32: Specimen preparation by vibratory compactor.
7 Preparation of test specimens
7.1 Core specimens
7.1.1 After determination of the bulk density of the core in accordance with EN 12697-6 (initial bulk density), if required, coat the split mould and base plate with a thin film of silicone grease and place a paper disc on the base plate.
NOTE The initial bulk density of the core may be determined, when it is required for comparison to the- refusal density as reference for it.
7.1.2 After removing any sealing compound (wax or tape) present, insert the core, with the flatter of its two ends uppermost, into the mould. Tighten the mould and clamp the mould to the base plate.
7.1.3 Place the assembly, without the shank and tamping foot but Including the additional base plate, in a preheated oven maintained at the compaction temperature defined in EN 12697-35 for the grade of binder in use. Retain in the oven until the centre of the core has attained the compaction temperature defined in EN 12697-35.
NOTE It may be found convenient to measure the temperature ola dummy specimen placed in the oven at the same time as the specimens to be compacted. The dummy specimen may have a thermocouple probe inserted into its centre.
7.1.4 Condition the operating mechanism of the vibrating hammer by running it for at least 2 mm on a dummy specimen before beginning LL and L1.Z.
7.1.5 Remove the assembly from the oven and place it on a level rigid floor. Ensure the mould is tightened until the split Is closed. Place a paper disc on the exposed surface of the core.
7.1.6 Immediately compact the core with the vibrating hammer, using the 102 mm diameter tamping foot, previously warmed to above 60 °C and coated with a thin layer of silicone grease. Hold the hammer firmly with the shaft vertical and move the tamping foot from one position to another around the mould in accordance with Z.LZ. Compact for 2 s to 10 s at each position. Move the tamping foot from one position to the next before material bulges above the edge of the tamping foot.
7.1.7 Position the tamping foot in contact with the side of the mould and compact the material in the following points of the compass sequence: N, S. W, E, NW, SE, SW, NE. Repeat the sequence until total compaction time period amounts to 2 mm ± 5 s.
To keep the mould in position whilst compaction is taking place, a panel of 20 mm plywood with a central hole of suitable dimensions to accommodate the mould base should be used. The operator should stand on the board to keep the assembly steady.
NOTE 1 The period of compaction at each position will depend on the material.
NOTE 2 A means of determining the downward force applied to the compaction hammer is described in A.i.3.
7.1.8 When the compaction period specified in LLZ is complete, remove any irregularities on the surface of the specimen by using the vibrating hammer fitted with the previously warmed 146 mm tamping foot coated with a thin layer of silicone grease.
7.1.9 Clamp the spare base plate, lightly greased, to the top of the mould. Invert the mould and remove the original base plate ensuring that a paper disc adheres to each end of the core. Place the original base plate in the oven; this now becomes the spare base plate. Drive the core into contact with the base plate with the vibrating hammer fitted with the 146 mm tamping foot coated with silicone grease.
7.1.10 Repeat the compacting procedure specified in Z1.&, LLZ and 7J.
7.1.11 Remove the base plate and the paper discs.
7.1.12 Allow the core to cool in air for at least 2 h and then remove it from the mould by loosening the screws and tapping the mould to destroy the adhesion.
7.1.13 Allow the core to cool to room temperature and then determine its bulk density in accordance with EN 12697-6 (refusal density) and its air voids content in accordance with EN 12697-8 (refusal air voids content).
7.2 Plant-mixed materials
7.2.1 Obtain a suitable quantity of loose plant-mixed material in accordance with EN 12697-27.
7.2.2 After conditioning the loose material fora period of 2 hat the compaction temperature defined in
EN 12697-35. carry out the compacting procedure specified in 2.L to 7.1.13 in order to determine the
refusal density only. For determination of compactibilit follow the additional requirements specified in EN 12697-10.
NOTE The object of a conditioning period, when the mixture Is held at a temperature equivalent to the compaction temperature. is to simulate site conditions. Binder absorption into the aggregate during this period has an effect on the properties of the compacted mixture.
7.3 Laboratory-mixed materials
7.3.1 Prepare the mixture prior to compaction in accordance with EN 12697-35.
7.3.2 Follow the procedure described in L22.
8 CalculatIon and expression of results
For refusal density and refusal air voids content, calculation and expression of results shall he in accordance with EN 12697-6 and EN 12697-8. respectively.
For compactability, calculation and expression of results shall be in accordance with EN 12697-10.
9 Test report
For all purposes, the test report shall make reference to this European Standard and shall include the following information:
a) identification of the mixture;
b) method of manufacture of the mixture, or if it was sampled from a compacted layer, location
of the sample.
For refusal density and refusal air voids content, the test report shall be prepared in accordance with EN 126976 and EN 12697-8. respectively.
For compactibility, the test report shall be prepared in accordance with EN 12697-10.BS EN 12697-32 pdf download.