Evaluation of Rutting Characteristics of Polymer Modified Bituminous Concrete Mix using Additives and GGBS as Filler Replacement
In the present study, polymer Modified Binder (PMB-70) was used in Bituminous Concrete Mix along with Ground Granulated Blast Furnace Slag as filler replacement along with two warm mix additives, viz., Sasobit and Zycotherm to study there performance. The Marshall Stability test were conducted for Polymer Modified Bituminous Concrete mix with and without filler replacement and with above additives to evaluate the optimum bitumen content, Optimum filler replacement content and Optimum additives content for conducting rutting test using Immersion Wheel Tracking Equipment. The filler replacement was varied from 0 to 10% in steps of 2% in the above mix. The Zycotherm content was varied from 0.05% to 0.15% in steps of 0.05% in the same mix. The Sasobit additive content was increased from 1% to 3% in steps of 1% in the above Polymer Modified Bituminous Concrete mix. The Marshall properties were analysed as per ASTM:D:1559-65 Rutting tests were carried out for four combinations of Polymer Modified Bituminous Concrete Mix, viz., Plain, with Optimized filler replacement, with Optimized Zycotherm content and Optimized Sasobit additive for varying thickness of 40mm, 50mm and 75mm.The optimized filler replacement content was found to be 6%(GGBS) and the Optimized values of warm mix additives, viz., Sasobit and Zycotherm were observed to be 1% and 0.15% respectively. The Polymer Modified Bituminous Concrete Mix with least thickness of 40mm was found to be highly rut resistant. Polymer Modified Bituminous Concrete mix with 6% GGBS and 0.15% Zycotherm additive showed higher number of passes indicating higher resistance to rutting.
Keywords - Additives, GGBS, Polymer Modified BC mix, Rut Depth.