from a precut slit the test specimen is held at one end by the pendulum and on the opposite end by a stationary member the loss in energy by the pendulum is indicated by a scale and pointer which registers in the force required to tear apart the specimen to a wet web of 25 100 mm long glass fibers derived from drainage of a white water slurry was added at room temperature a standard urea formaldehyde binder containing 1 wt styrene acrylate acrylonitrile polymer modifier i e acronal s 886 s supplied by basf to provide a fiber to modified binder weight ratio of about 80 20 the web containing fibers and modified binder is then sprayed with an aqueous solution of poly dimethylsiloxane supplied by chem trends as product rctw b9296 to provide a polysiloxane concentration of from 0 25 to 5 with respect to uf as noted in the following table the resulting webs were then dried and cured at about 300 u00b0 c for a period of 10 seconds to produce cured non woven mats after which the mats were coated on both sides at 215 u00b0 c with filled asphalt comprising 32 w w asphalt and 68 w w limestone filler using a two roller coater the styrene butadiene latex employed in the examples was supplied dow chemical co and the urea formaldehyde binder was obtained from leste co the results of these tests are as reported in following table 2 it will be understood that many modifications in procedure and substitutions in the compositions of examples 2 6 including substitution of the polysiloxane binder and binder modifier as well as fibers or fiber mixtures can be made without departing from the scope of the present invention and that these.