Question

-------------high way materials-----------------------------

asphalt cement is supplied as PG 70-34. what high and intermediate temperatures will it be tested in the DSR? What temperature will it tested for cold temperature properties?  Is this binder likely to be polymer modified? What rule of thumb are you using to base your answer?

Answer 1

The above table can be used for better understanding.

Basically in DSR test the sample is tested for temperatures from -40 to 200 degree C.

The basic DSR test uses a thin asphalt sample sandwiched between two circular plates. The lower plate is fixed while the upper plate oscillates back and forth across the sample to create a shearing action.

• DSR tests are conducted on unaged, RTFO aged and PAV aged asphalt binder samples.

• Test temperatures equal or greater than 46°C use a sample 1 mm thick and 25 mmin diameter (Unaged asphalt binder and RTFO residue).

• Test temperatures inclusively between 4°C and 40°C use a sample 2 mm thick and 8 mm in diameter (PAV residue).

With 4-mm parallel plates, frequency sweeps from 0.1 to 100 rad/s are performed at different low temperatures (0 to −35°).

PMB consists of bitumen blended with a synthetic polymer or crumb rubber. PMBs are used to enhance the performance of binders on heavily trafficked or distressed pavement surfaces, often in adverse climatic conditions.PG 70-40 such a high performance can be achived from polymer modified binder but we cannot just say it as polymer modified because it depends on its configuration i.e., its constituents.