According to Article 4.3.5-D-1 of the 1956 Edition of Kentucky's Standard Specifications for Road and Bridge Construction, a minimum of two rollers, one 3-wheeled roller and one tandem roller, shall be required on each state project involving bituminous concrete paving operations. A further requirement of the specifications is that additional rollers will be provided so that there is avaHable "...at least one roller for each 30 tons of the bituminous mixture per hour..." that is laid. This, of course, means that for paving operations involving the laying of the bituminous mixture at rapid rates, the contractor must have available and make use of an increased number of rollers.

With the wide spread use in Kentucky of dense graded aggregate as a base course material, there is also an increased use of vibratory rollers to obtain the desired densities of the base. Very often then, the paving contractor will have available on the job site such vibratory compacting equipment. Current practice does not permit the use of this equipment for compacting the bituminous mixture and thus the vibratory roller usually stands idle during the laying of the bituminous mixture. From the contractor's point of view, it would be highly desirable if this equipment could be used to satisfy the specification requirements for the additional rollers as stated by Article 4.3.5-D-1 and thus reduce the contractor's in vestment in compacting equipment.

Report Date


Report Number

No. 157

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