8/10/2019 Bitumen Rheology Coursework

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THE UNIVERSITY OF NOTTINGHAM MALAYSIADEPARTMENT OF CIVIL ENGINEERING

Module Title: ADVANCED PAVEMENT MATERIALS

Module Code: H24PAM

Session: 2014-2015

Semester: Autumn

Coursework-1: Rheological Analysis of Bitumen

Assessment value: 15% of total assessment

Introduction

Rheological data has been generated for three bitumens consisting of a penetration grade

bitumen, an EVA polymer modified bitumen (PMB) and a SBS PMB using the DSR. Youare asked to analysis the data using a range of rheological data presentation techniquesand plots and then comment on the effect of polymer modification compared to theunmodified penetration grade bitumen.

Current Form of Data

The rheological data has been measured within the linear viscoelastic region ofresponse of the binders using two testing geometries:

8 mm parallel plates with a 2 mm gap

25 mm parallel plates with a 1 mm gap

The data has been generated by undertaking frequency sweeps (0.01 Hz to 15 Hz) atdifferent temperatures ranging from 10C to 75C. The smaller (8 mm) geometry hasbeen used at low temperatures while the larger (25 mm) geometry has been used at

high temperatures. For all three binders there has been an overlap of rheological datawhere measurements have been taken with both parallel plate geometries at the sametemperature(s). The rheological data has then been grouped together into 5 tables in aspreadsheet. Each table has a particular rheological parameter (e.g. phase angle,complex viscosity, complex modulus, etc) as a function of frequency and temperature{reddata from 8 mm geometry}. You will only need to use the phase angle and complexmodulus data.

Tasks

You are asked to undertake the following tasks:1.

Produce isothermal plots of phase angle () and complex modulus (G*) on

separate graphs using all the rheological data (both testing geometries).2. Select the appropriate testing geometry at the temperatures where there is data

overlap using you knowledge of testing compliance errors (see Note 1).3.

Comment on why you have selected a particular testing geometry over another.4. Use the now adjusted isothermal plots (remove data associated with incorrect

testing geometry) to produce master curves of complex modulus versus frequency

and phase angle versus frequency at a reference temperature of 25C. Yourhorizontal shifting of complex modulus and phase angle data can be done either

graphically or using a calculation routine in a spreadsheet. Youmay also want to

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try calculating the shift factor versus temperature relationship using either theWLF equation or the Arrhenius equation and then use this shift factor/temperaturerelationship to shift the rheological data (see Note 2).

5. Comment on the method you used and the ease/difficulty involved in generating

the master curves.6. Comment on the shape and smoothness of the final master curves for the three

binders.7. Produce Black diagrams for the three binders.

8. Comment on the similarities/differences between the Black diagrams and mastercurves for the three binders

Note 1

In theory the rheological parameters (G*, , etc) should be the same irrespective oftesting geometry (8 mm or 25 mm parallel plate geometries) if the binder is tested at the

same temperatures, frequencies and within the linear viscoelastic response of thematerial. However, we know that there will be slight differences between testinggeometries due to compliance errors. These errors can be identified by comparingisothermal plots of the rheological data from the two testing geometries.

Note 2

Master curves can be generated by shifting (horizontally) isothermal plots of therheological parameters (G*, , etc) determined as different temperatures to a singlereference temperature. The amount of shifting is covered by a shift factor versustemperature relationship which can be modelled using either a WLF equation or an

Arrhenius equation. However, master curves can be formed by manually shifting the databased on either graphical or mathematical techniques without the need to establish thecomplete shift factor/temperature relationship. To do this you would need rheologicaldata that overlap at different temperatures and was therefore able to be shiftedhorizontally to lie on one continuous line (master curve).

Reporting

1. Produce plots for the three binders as described above.2. Produce descriptive comments on the various aspects of the data analysis and

presentation techniques and methods.

Supplementary Information

Penetration grade bitumen data: Microsoft Excel Workbook DSR Data Pen Bitumen

EVA PMB data: Microsoft Excel Workbook DSR Data EVA PMBSBS PMB data: Microsoft Excel Workbook DSR Data SBS PMB