AS NZS 2891.5:2015 pdf download.Methods of sampling and testing asphalt Method 5: Compaction of asphalt by Marshall method and determination of stability and flow- Marshall procedure.
3 DEFINITIONS
For the purpose of this Standard, the definitions in AS/NZS 2891.1.1 apply.
4 APPARATUS
The following apparatus is required:
Balance Of suitable capacity with a limit of performance not exceeding ±0.5 g.
Breaking head Consisting of upper and lower cylindrical segments having an inside cylinder face accurately machined. The lower segment is to be mounted on a base having two perpendicular guide rods or posts extending upwards. Guide bushes on the upper segment are to be in such a position as to direct the segments together without binding or loose motion of the guide rods. The breaking head shall have an internal diameter of 101.6 ±0.2 mm. A typical breaking head is shown in Figure 1.
Compaction hammer Mechanical or hand and consisting of a 98.5 mm diameter flat circular tamping face and a 4.53 ±0.02 kg sliding weight with a free fall of 457 ±1 mm. A suitable design for a hand compaction hammer is shown in Figure 2. Designs for mechanical compaction hammers may vary as long as the essential dimensions are met.
NOTE: Although the design, dimensions, mass and height of mass drop for hammers may comply with this specification, variations in efficiency may mean density achieved in compacted specimens with the same number of blows may vary between compaction apparatus. It is up to individual users to ensure the compaction apparatus is operating correctly and efficiently. This may be achieved through inter laboratory assessments or proficiency testing schemes.
Compaction pedestal Consisting of a wooden block approximately 200 mm x 200 mm x 450 mm capped by a steel plate approximately
300 mm x 300 mm x 25 mm. A typical compaction pedestal is shown in Figure 3. The air dry density of the wooden block shall be 670 kg/rn3 to 770 kg/rn3. The plate shall be level and securely attached to the block, which in turn shall be secured to a solid concrete floor or slab. A suitable framework shall be secured to the pedestal to ensure that the compaction hammer is kept vertical. Wooden block dimensions for length may vary to accommodate multi-head compactors.
NOTE: Certain designs of dual head compactors are supplied fitted to a steel plate approximately 400 mm x 400 mm x 25 mm and are bolted directly to a dense concrete block approximately 400 mm x 400 mm x 450 mm which is secured to the solid concrete floor or slab. This type of pedestal has been found to be an acceptable alternative.
7 COMPACTION OF SPECIMENS
The compaction procedure shall be as follows:
Remove the mould from the oven. Place a thermometer in the mould and verify that the temperature of the asphalt in the mould is within the tolerance for the compaction temperature specified in Tables 1, 2 or 3. Record the temperature.
Place a circular paper disc on top of the asphalt and transfer the mould assembly to the compaction pedestal.
At a rate of 60 to 70 blows per minute, compact the mix using the specified number of blows of the compaction hammer with the hammer axis held vertically. Invert the mould and apply the same number of blows to the other end of the specimen.
NOTES: 1 Where the number of blows is not specified, 50 blows is commonly used.
2 Some laboratories that use dual head automatic hammers invert and swap the two moulds such that each mould receives the same compaction energy averaged between two hammers.
3 Where hand compaction is used the sliding mass of the compaction hammer should be raised to its highest position without lifting the face of the hammer from the surface of the asphalt. Immediately after the sliding mass has reached the bottom of its free fall it should be caught such that it does not bounce on to the specimen creating additional compactive effort.
Repeat Steps (a) to (c) to produce a minimum of two specimens, these operations being continuous to minimize heat loss. Retain the specimens in the moulds and remove the paper discs from their faces. Mark the top of each specimen with an identification number. Remove the specimens from the moulds using the specimen extraction equipment and allow the specimen to cool. NOTE: Care should be taken to ensure that the specimen has cooled sufficiently to ensure that it does not deform when removed from the mould.AS NZS 2891.5 pdf download.