engleski

Predicting Useful Lifetime of Polymer Modified Bitumen

Predicting the stability of materials under constant load and the useful lifetime of materials for engineering application is of significant value. Creep studies are particuarly valuable for determining the long term properties of a material and its ability to withstand loading and deformation influences in use. In this work the dynamic mechanical behaviour of bitumen, BIT, and styrene-butadiene-styrene, SBS, modified bitumen were studies using dynamic mechanical analysis, DMA. The possibility of using the data obtained by dynamic mechanical analysis, and time- temperature superposition principle for predicting useful lifetime of polymer modified bitumen is also desribed in this paper. The BIT/SBS blends were investigated in creep fatigue regime at temperature 10, 20, 30, 40 and 50 oC. At the constant load the creep values of BIT/SBS blends increase and those of creep modulus decrease over a period of time. These effects are more pronounced in samples with higher content of SBS. The time- temperature superposition principle was applied to create master curves for the reference temperature 10 oC for the creep modulus of BIT/SBS blends. A master curve is of great value because it covers times of frequencies outside the range accessible by experiment. Obtained master curves indicated that increase of SBS content icnreasing useful lifetime of BIT/SBS blends. The degree of horizontal (time) shifting required to superimpose a given set of data upon a reference is well described with respect to temperature with WLF equation.

bitumen; polymer bitumen; phases; traffic stress; stability; deformation; useful lifetime predicting

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