EVALUATION OF A BITUMEN MODIFIER WITH DIFFERENT ADDITIVES

Abstract

Flexible pavements with bituminous surfacing are widely used in India. Performance and durability of these pavements have greater influence by strength and hence designing a road with a strong bituminous base course like DBM can provide the load-bearing capacity needed to handle heavy axle loads. Strong base course also provides the load-spreading ability to relieve stress and strain coming on the subgrade layer. The strength property of pavement is closely related to the characteristics of pavement materials and additive. The present study is undertaken to see the effect of a commercially available Asphalt extender (AE) on strength properties of DBM mixes with different types of aggregates and with and without adhesive agents (additives). Four types of aggregate namely Limestone, Quartz, Granite, Sandstone and two types of additives lime and cement were used in their different proportions. Various laboratory tests like Marshall Stability, Tensile Strength Ratio, Retained Stability and Unconfined Creep Tests were conducted on specimens prepared by two different types of binders namely bitumen of VG 30 and another with 60% Bitumen + 40% AE. All test specimens were prepared using Marshall method of mix design. The performance of asphalt roads can be considerably improved, by using a significant amount of AE replacing part of the bitumen in the conventional hot mix asphalt. The target applications for this technology are the binder and base courses in the road structure in order to benefit from the enhanced structural properties that it provides.