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The paper presents the details of various investigations conducted for the laboratory evaluation of the performance of crumb-rubber modified asphalt mixes. Crumb rubber (CR) obtained from discarded truck and bus tires was used to modify 80/100 penetration grade asphalt cement. Fatigue and permanent deformation characteristics, temperature and moisture susceptibility, and oxidative aging are some of the performance indicators of mixes evaluated. A static indentation test was adopted for assessing the relative permanent deformation characteristics of different mixes. Three aggregate gradations: (1) superpave; (2) gradation specified by the Ministry of Surface Transport, India for asphalt concrete; and (3) one gap gradation, were considered in the investigation. Compared to normal mixes, CR modified mixes were found to have improved fatigue and permanent deformation characteristics. They also showed lower temperature susceptibility and greater resistance to moisture damage compared to normal mixes. Superpave mixes gave better overall performance compared to the mixes having other aggregate gradations. CE Database subject headings: Rubber; Binders, materials; Asphalt mixes; Laboratory tests; Fatigue strength; Deformation.

Low-grade laterite and pit-run gravel aggregates available in abundance in eastern India may be turned into a cost-effective base for low-volume roads when ordinary portland cement, river sand, and aggregates are mixed in a 1:6:12 proportion by weight. 152 x 152 x 152 [mm.sup.3] cubes were cast at several water-cement ratios and the mix was compacted by a vibratory plate compactor. The compressive strength test was determined for different water-cement ratios, and the one that gave the maximum strength was used to prepare 102 x 102 x 508 [mm.sup.3] beam specimens. A number of cubes and beams were kept inside airtight polyethylene bags for accelerated curing at a temperature of 50 [degrees] C. Modulus of rupture and flexural fatigue tests were carried for the evaluation of pavement design parameters. A methodology of design of a lightly cemented pavement along with an example are also presented.