Conclusions from experiments on bitumen

The results mentioned indicate that the scattering is too large, and therefore the coefiB-cients of correlation are to small, to obtain a positive description of the consistency data of 

The second objective of this investigation was an attempt to correlate the index numbers of thermogravimetry with analytical data of the bitumens. Very good results were found for the correlation of the means of the residues at 600 °C or 800 °C with the means of the H/C ratio (Fig. 4-49), where coefficients of correlation 0.97 were found. 

There is a relationship between the mean molecular weight, the start temperature of the evaporation T5 %) and the distillable fraction (AG400) for bitumen and its colloid components (Fig. 4-50 to 4-53). The dispersion medium shows the highest values for the coefficients of correlation, which decrease via the petroleum resins down to the asphaltenes. There is no dilFerence between distillation and blown bitumens. 

The residue at 600 °C or 800 °C respectively may be correlated fairly with the concentration of colloids (total petroleum resins and asphaltenes). Here also the distillation and the blown bitumens fall on the same straight line (Fig. 4-54 and 4-55). Correlation of the maximum of the reaction rate DTG with the concentration of the colloids results in two regression lines for the distillation bitumens, and a third line for the blown bitumens (Fig. 4-56). 

The concentration of the dispersion medium determines the evaporation start temperature (Tl % OT T5 %) of the distillation bitumens (Fig. 4-57). For the blown bitumens no relation was found, but for both the distillation and the blown bitumens a clear correlation of the distillable fraction AG400 with the concentration of the dispersion medium was recognized (Fig. 4-58). 

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