From 1994 to 2004, the Pavement Coatings Technology Center at the Department of Civil & Environmental Engineering, University of Nevada – Reno conducted field studies. Industry used results of these studies to develop standards and develop application recommendations.
One study looked at the resistance to wear under normal traffic conditions over 4 years of pavement using sealcoat with different sand loadings. The sand loading study is summarized in an information sheet posted here. As a result of this study, PCTC made the following recommendation:
Based on this study, the PCTC strongly recommends that the sealer be designed to account for the unique characteristics of the coal tar binder and the sand that are being used on the job, and sealer designs with high sand loadings, above 5 lbs., should not be accepted.