AIRFIELD MARKING PAINTS - IV. EFFECT OF PAINT FLEXIBILITY ON SLURRY-SEALED ASPHALT.

A field exposure study was conducted on experimental airfield marking paints with relatively high flexibilities. While flexibility must be greater than the minimum required in Federal Specification TT-P-85b for good paint performance, a further increase in flexibility does not necessarily result in better performance. Short oil length alkyd and oleoresinous paints do not perform well medium oil length paints performed very well longer oil length paints generally performed somewhat poorer than medium oil length paints, especially for the alkyd formulations. While incorporation of organic plasticizers into paints generally increased flexibility, it did not usually improve the field performance. A statistical analysis of the test variables revealed the following Oleoresinous phenolic varnish generally performed better than alkyd paint stripes. Lifting was greater for double-thickness thickness stripes than for single-thickness stripes. Cracking was faster for long oil than medium oil alkyd paints and for medium oil than for long oil oleoresinous paints. Medium oil paints had less cracking overall than long oil paints. There was generally less cracking and lifting with paints containing no plasticizer than those with one. Tricresyl phosphate formulations generally had less edge cracking and lifting than comparable formulations with dibutyl phthalate as a plasticizer. There was a high correlation between edge cracking and the lifting of slurry seal. Author