# Experimental Study on Physical and Rheological Properties of Trinidad Lake Asphalt Modified Binder
## 2 Materials and Methods
### Physical Properties Tests  
The penetration test at 25 \({}^{\circ}\)C, softening point test, and Fraass breaking point test were performed to evaluate the physical properties of the 35/50 bitumen, the TLA and the TLA-modified binders. The penetration tests were performed according to the European standard [21] to evaluate the hardness of bitumen, TLA and binders. The softening point tests were performed according to the European standard [22] to determine the temperature at which a phase change occurs in bitumen, TLA and binders. The Fraass breaking point test following the European standard [23] was undertaken to evaluate the brittleness of bitumen and binders at low temperatures. The results of the physical tests of the base bitumen and the TLA are given in Tables 1 and 2, while the results for the TLA-modified binders are given in Table 3.  
The conventional mixing formulas (1) and (2) were also used to determine the penetration and softening point of the TLA-modified binders as follows [28]:  
\[P_{mix}=(P_{A})^{a}\cdot(P_{B})^{b}, \tag{1}\]  
\[SP_{mix}=aSP_{A}+bSP_{B}, \tag{2}\]  
where:  
* \(P_{mix}\)--the estimated penetration of the modified binder;
* \(SP_{mix}\)--the estimated softening point of the modified binder;
* \(P_{A}\) and \(P_{B}\)--the measured penetrations of two components: base bitumen (A) and TLA (B), respectively;
* \(SP_{A}\) and \(SP_{B}\)--the measured softening points of two components: base bitumen (A) and TLA (B), respectively;
* \(a\) and \(b\)--the proportions of components (A) and (B) in the mixture, respectively (\(a+b=1\)). Additionally, the plasticity range and the penetration index were determined using the experimental values of penetration, softening point, and Fraass breaking point. The plasticity range (PR) is the difference between the softening point and the Fraass breaking \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Properties**} & \multirow{2}{*}{**Unit**} & \multirow{2}{*}{**35/50 (Base)**} & **35/50** & **35/50** & **35/50** & **35/50** & **35/50** \\  & & & **+10\%TLA** & **+20\% TLA** & **+30\% TLA** & **+40\% TLA** & **+50\% TLA** \\ \hline Penetration at 25 \({}^{\circ}\)C & [\(\times\)0.1 mm] & 42.8 \(\pm\) 0.8 & 39.9 \(\pm\) 1.2 & 31.8 \(\pm\) 1.9 & 25.9 \(\pm\) 0.4 & 23.3 \(\pm\) 0.4 & 21.2 \(\pm\) 0.3 \\ Softening point & [\({}^{\circ}\)C] & 55.1 \(\pm\) 0.6 & 56.9 \(\pm\) 0.5 & 59.3 \(\pm\) 0.2 & 60.2 \(\pm\) 0.6 & 61.2 \(\pm\) 0.3 & 62.6 \(\pm\) 0.2 \\ Fraass breaking point & [\({}^{\circ}\)C] & \(-\)13.0 \(\pm\) 1.5 & \(-\)12.0 \(\pm\) 2.4 & \(-\)12.0 \(\pm\) 2.1 & \(-\)11.0 \(\pm\) 0.9 & \(-\)10.0 \(\pm\) 0.9 & \(-\)8.0 \(\pm\) 1.6 \\ Plasticity range (PR) & [\({}^{\circ}\)C] & 68.1 \(\pm\) 1.5 & 68.9 \(\pm\) 2.5 & 71.3 \(\pm\) 2.2 & 71.2 \(\pm\) 0.9 & 71.2 \(\pm\) 0.9 & 70.6 \(\pm\) 1.6 \\ Penetration index (IP) & [\(-\)] & \(-\)0.35 \(\pm\) 0.13 & \(-\)0.14 \(\pm\) 0.10 & \(-\)0.14 \(\pm\) 0.13 & \(-\)0.40 \(\pm\) 0.11 & \(-\)0.39 \(\pm\) 0.06 & \(-\)0.32 \(\pm\) 0.04 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Basic physical properties of TLA-modified binders. point in [\({}^{\circ}\)C]. Within the plasticity range, the binder maintains its viscoelastic properties. The penetration index (IP) is a dimensionless value to measure of temperature sensitivity of the binder. The lower the penetration index, the greater the temperature sensitivity of the binder. The determination of the penetration index according to the European standard [25] assumes that the binder at the softening point has penetration equal to 800 [0.1 mm]. However, the applicability of these physical parameters to evaluate temperature sensitivity and the viscous properties of binders is relatively often questioned. Instead, the dynamic shear rheometer (DSR) tests are used to determine these binder properties. Moreover, to evaluate the pavement performance regarding deformation or cracking under extreme service temperatures, the determination of the rheological parameters (complex modulus, phase angle, etc.)