Marshal stability test apparatus

The test is applicable to hot mix designs using bitumen and aggregates upto a maximum size of 25mm. In this method, the resistance to plastic deformation of cylindrical specimen of bitumenous mixture is measured when the same is loaded at periphery at 5 cm per min. This test procedure is used in designing and evaluating bitumenous 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, a) density – voids analysis b) Stability – flow tests. The marshall stability of mix is defined as a maximum load carried by a compacted specimen at a standard test temperature of 60ºC. The flow value is deformation the marshall test specimen under goes during the loading upto the maximum load, 0.25 mm units. In this test and attempt is made to determine optimum binder content for the type of aggregate mix and traffic intensity.