Flexible pavement/ bituminous road is the major type of highway in india. the ingredients of a bituminous pavement are bitumen, aggregates and filler. the cost of bitumen is equivalent to sugar. however, whenever, a new pavement is constructed, the old bituminous material goes into the landfill or rest beneath the new overlay layer. in the last decade, many r&d institutes such as central road research institute (crri), iits and nits have started exploring the recycling of bituminous material. nhai has issued a technical circular to reuse the rap material in service lane of the pavements. indian roads congress issued a technical specification i.e. irc 120: 2015 for hot and cold recycling of rap material. however, the maximum percent of rap material in new hot mix asphalt pavement is generally limited to 30% only. the reason is a lack of confidence in the performance of the recycled mix in the long term and limited use of the recycling agent. in our study, we have used a soft paving grade of india i.e. vg-10 having a viscosity of 1164 poise at 60°c, confirming to indian standard: 73 (2013). the rap content varies from 0, 15, 25, 40, 65, 80 and 100%. the unique feature of this study is that the present binary mixing laws for estimating the allowable rap content are examined for their applicability with vg-10 as a recycling agent. the parameters used to examine the applicability of mixing laws are following: "zero shear viscosity (zsv) at 60°c", "rotational viscosity at 135°c and 150°c", "high pg temp. from dynamic shear rheometer" and conventional "softening point". the first parameter i.e. zsv is a replacement of absolute viscosity. the measurement of absolute viscosity by conventional cannon manning viscometer is difficult due to high stiffness of rap binder. hence the applicability of zsv as replacement of absolute viscosity by cannon manning viscometer is also examined. the "softening point" and "high pg temp." are widely used in europe and the usa for finding the allowable rap in the hot recycled bituminous pavement. this study demonstrates the applicability of mixing laws such as "arrhenius", "grunberg & nissan", and "chevron" for hot mix asphalt recycling process.