Marshall Stability and Compaction
Originally developed by Bruce Marshall, a highway engineer in U.S.A later on standardised by ASTM. Generally the test is applicable to hot mix designs using bitumen and aggregates upto a maximum size of 25 mm.
In this method the resistance to plastic deformation of cylindrical specimen of bituminous mixture is measured when the same is loaded atperiphery at 5 cm per min. This test procedure is used in designing and evaluating bituminous paving mixes. The test procedure is extensively used in routine test programmes for paving jobs There are two major features of the Marshall method of designing mixes namely.
- Density – voids analysis
- Stability – flow tests.
The apparatus consists of: 1. A loading unit motorized, capacity 5000 kgf with two telescopic pillars and an adjustable cross head Limit switches are fitted inside to control upward or downward movement of the pillars. On – off reversing switch and indicator lamps are on the front side while a hand wheel to manulally move the pillars minute operated on 230 Volts A.C.
- 1 No. Compaction pedestal with specimen mould holder
- 2 Nos. Compaction Rammers, 4.5 kg weight and free fall 45.7 cm.
- 1 No. Breaking head assembly with provision to fix flow meter
- 3 No. Specimen mould 10.16 cm I.D. x 7.6 cm high with base plate and extension collar
- 1 No. Kit for specimen extraction, consists of one each load transfer bar, steel ball, specimen exacting plate.
- Flow meter (dial gauge) grasuated 0.01 mm x 25 mm travel
- Fitted with a stem brake unit to indicate maximum deflection Complete as above.
High sensitivity proving Ring 2500 kg capacity fitted with 0.002 mm dial gauge and our own test certificate. Complete in a nice wooden carrying case.