Determining The Marshall Stability of Bituminous Mixture

What is the Marshall Test?

The Marshall stability test is used to assess the stability, flow, voids, voids in mineral aggregates, voids filled with asphalt, and density of the asphalt mixture.

OBJECTIVES

The objective is to assess the Marshall Stability Value and flow value of the provided bitumen mixture in order to determine its strength and flexibility.
The aim is to conduct a density-voids analysis on the given bituminous mixture.
The goal is to evaluate the suitability of the bituminous mixture in meeting the specified criteria for the surface course.

PREPARATION OF TEST SPECIMEN

The proportions of coarse aggregates, fine aggregates, and filler materials must be determined in order to meet the standards’ specifications. The necessary amount of the mixture is selected to create compacted bituminous mix samples with an approximate thickness of 63.5 mm.
Utilize 1200 gm of coarse aggregates, fine aggregates, and filler material (according to the grading requirement provided in the table) to achieve the desired thickness.
The aggregates need to be heated to a temperature ranging from 175°C to 190°C.
Make sure to clean and pre-heat the compaction mould assembly and rammer to a temperature ranging from 100°C to 145°C.
Heat the bitumen to a temperature of 121°C to 138°C and add the required amount to the heated aggregate.
Mix the components well using a mechanical mixer or by hand with a trowel.
The mixing temperature for 110 grade bitumen should be approximately 154°C, while for 60/70 grade, it should be around 160°C.
Compact the total mix in a mould using a rammer with 75 blows.
Reverse the specimen and compress the opposite side using an equal number of strikes. The compaction temperature must reach approximately 138°C for 80/100 grade bitumen and 149°C for 60/70 grade.
After compaction, invert the mould, remove the base with the collar from the bottom, and extract the sample by pushing it out with the extractor.
The compacted specimen should have a thickness of 63.5 mm.
Allow the sample to cool for a few hours.
Finally, measure the sample’s mass in air and submerged to determine the density of the specimen and calculate the voids properties.