Tech Today

Revisiting mod bit testing

NRCA has conducted limited testing of polymer-modified bitumen sheet products. This testing is a follow-up to similar testing conducted in 2011 where 10 of the 16 products evaluated did not achieve physical property levels prescribed in ASTM International product standards.

Product testing

In 2015, NRCA obtained full rolls of 13 new (uninstalled) polymer-modified bitumen sheet products from eight manufacturers; 11 products were SBS polymer-modified, and two were APP polymer-modified. The samples were obtained from NRCA contractor members throughout the U.S. from their stored stocks.

Product specimens were tested for low-temperature flexibility before and after heat aging and granule loss according to applicable ASTM International test methods. Test results are shown in the figure.