Performance evaluation of Cement Grouted Bituminous mixes

Cement Grouted Bituminous (CGB) mix is a semi flexible type of pavement material which essentially is an open graded (porous) bituminous mix grouted with cement mortar. CGB mixes have the advantages of both flexible and rigid pavements. This hybrid mixture provides good rutting and top-down cracking resistance. In the present study, an effort was made to evaluate the performance of CGB mixes. The study consists of selection of an appropriate gradation, design of cement mortar and performance evaluation of CGB mix. Performance of CGB and normal mixes was evaluated by conducting beam fatigue and static indentation creep tests. Correlations developed between the quantity of grout penetrating the mix with the air voids in dry aggregates and voids in mix will be useful for selecting suitable aggregate gradations. Different strength parameters of the mix improved significantly due to grouting. Resistance to moisture damage also improved. CGB mixes had much longer fatigue lives compared to unmodified mixes. Rutting performance of CGB mix, as observed in the static indentation creep test, was observed to be significantly better than that of normal mix. Results obtained from the investigations suggest that cement grouted bituminous mix can be a promising material for surface layers.