CUTBACKBitumen Primer -IS:217 & IRC:16
CUTBACK BITUMEN is low viscosity, cold applied bituminous primer. Cutback Bitumen is produced by fluxing bitumen with distillates of petroleum for use in road construction.A bituminous or an absorbent surface preparation before any super-imposed treatment/construction. The objective of priming is to promote adhesion between the existing surface and the super-imposed treatment or construction.
The choice of a bituminous primer shall depend upon the porosity characteristics of the surface to be primed.Cutback bitumen Primer is classified into rapid curing (RC), Medium Curing (MC) & Slow Curing (SC) based on viscosity.
PREPARATIONOF ROAD SURFACE:
The surface to be primed shall be swept clean,free from dust and for best results to be dry.Potholes,depressions,large irregularities, etc.shall be repaired prior to priming.Minor depressions and holes may be ignored until after the surface is primed,after which they should be patched with suitable premixed material prior to the surface treatment. Traffic shall be kept off the prepared area prior to priming.
CUTBACK BITUMEN PRIMER shall be sprayed uniformly over the dry surface preferably using mechanical sprayers. The primer shall be applied at the rate of 0.75kg to 1.5 kg.per sq.mtr.Depending on surface of low porosity to high porosity. Application temperature of primer need only be enough to permit the primer to be sprayed effectively through the jets of the sprayer and to cover the road surface effectively. Generally it may vary from 40 to 80°C for the range of viscosities of the primer, Any pools of excess primer left on any part of the surface shall be swept out over the adjacent surface, and then a light spreading of sand shall be applied. The primed surface shall be allowed to cure for not less than 24 hours. During this period traffic shall be kept off of the primed surface.