Marshall stability test is applicable to hot mix designs using bitumen and aggregates up to a maximum size of 25mm. In this procedure, the resistance to plastic deformation of cylindrical specimen of bituminous mixture is calculated when the same is loaded at periphery at 5 cm per min.
The two prime features of the Marshall method of designing mixes are :
- Density – Voids Analysis
- Stability – Flow Tests
This test method is used in the design and evaluation of bituminous paving mixes. The test method is widely used in routine test programmers for paving works.
The Marshall stability test apparatus comprises of :
- A loading unit motorized, capacity 5000kgf with two telescopic pillars and an adjustable cross head. The Limit switches are attached inside to regulate the upward or downward movement of the pillars. On off reversing switch and indicator lamps are on the front side while a hand wheel to manually displace the pillars is on the right side. The load frame has fixed speed of 5.80cm per minute, which is operated on 230 volts AC
- 3 Specimen mold 10.16cm I.D. x 7.6cm high with base plate and extension collar
- One Kit for specimen extraction that consists of one each load transfer bar, steel ball and specimen extracting plate
- One number compaction pedal with specimen mold holder
- 1 Breaking head assembly with provision to fix flow meter. The Marshal Stability of mix can be defined as a maximum load carried by a compacted specimen at a standard test temperature of 60ºC