Although cementbased overlays have been around for decades, many of today's systems blend polymer resins with cement, sand, and other additives to improve performance, wear resistance, and aesthetic qualities. Polymermodified overlays can be applied in layers as thin as a credit card or up to several inches thick without delamination or failure.
Supplementary cementing materials (SCMs) contribute to the properties of hardened concrete through hydraulic or pozzolanic activity. Typical examples are fly ashes, slag cement (ground, granulated blastfurnace slag), and silica fume. These can be used individually with portland or blended cement or in different combinations.