Physical and Mechanical Properties of Epoxy–Bauxite Mortar of High-Friction Surface Treatment

Abstract

Highfriction surface treatment (HFST) has been widely utilized by state departments of transportation (DOTs) to reduce friction related vehicle crashes. However, although many studies have been conducted to enhance the durability of HFST, limited information is available on the properties of the HFST epoxy–bauxite mortar. Although an HFST may contribute little to the pavement structural capacity, its epoxy–bauxite mortars have several distinguishing properties that may result in incompatibilities between the HFST and underlying pavement. Consequently, knowledge of the HFST epoxy–bauxite mortar properties is critical to ensuring its durability. This paper determined the physical and mechanical properties of epoxy–bauxite mortar for HFSTs. An empirical method was developed to estimate an approximate binder content. Comprehensive laboratory testing determined the properties, including density, Poisson’s ratio, coefficient of thermal expansion (CTE), dynamic modulus, and crack resistance. It was found that the HFST epoxy–bauxite mortar has a CTE significantly higher than that of hot-mix asphalt (HMA) mixtures and portland cement concrete (PCC). The HFST epoxy–bauxite mortar basically is a viscoelastic material with very low water-absorption ability and a dynamic modulus greater than that of a HMA mixture. The test results of fracture energy, tensile strength, and crack progression rate (CPR) consistently indicated that the HFST epoxy–bauxite mortar has very good cracking resistance.