Pavement Design for Rural Low Volume Roads Using Cement and Lime Treatment Base

Quantity road aggregates have become rare and costly in many places in India due to massive construction activities required for the development of new infrastructure facilities. The pavement industry looks for ways of improving lower quality materials that are readily available for use in roadway construction. Cement/ lime treatment has become an accepted method for increasing the strength and durability of soils and marginal aggregates, reducing quantity of aggregates. Indian Roads Congress (IRC) developed a Special Publication (SP) for mix design of lime/cement treated base/subgrade. No pavement design guideline is presently available for cement/lime treated base. To overcome this problem, the objective of the present research work is to develop a pavement design chart using cement and lime stabilized base for rural roads with light to medium traffic (Traffic level up to 5 million standard axles). Based on this objective ,the scope of the present research work is limited to develop a pavement design chart varying California Bearing Ratio (CBR) of subgrade and thickness of stabilized material as well as axle load repetition up to 5 million standard axles (MSA).Charts have been developed using FPAVE software. Results indicated that at known particular resilient modulus of stabilized base and CBR of subgrade, thickness of soil-cement base and that of soil-lime sub-base increase with increasing the allowable number of load repetitions. Thickness of soil-cement base and that of soil-lime sub-base decrease as moduli of soil-cement base and soil-lime base increase. For each modulus of soil-cement base and soil-lime sub-base, as CBR is increased, thickness of soil-cement base and that of soil-lime sub-base decreased significantly. At a particular resilient modulus, CBR and N, the thickness of soil-cement base is less than that of granular base. Finally, design curves have been developed to estimate thickness of soil-cement base and that of soil-lime sub-base for different N-values and different values of modulus of soil-cement and soil-lime mix.