Aspartic resins have been a popular addition to polyurea coatings since Bayer Corp. invented aspartic ester—a unique kind of reactant—in the 1990s. The resulting polyaspartic polyureas are very dense and highly resistant to abrasion and UV fading. These coatings penetrate more deeply into concrete surfaces than other polyureas, effectively blocking moisture below the surface. Polyaspartics typically are not cost-effective for large projects. The fast-setting resins are better for small, one-day jobs that require quick return to service; a topcoat can handle foot traffic within a few hours. The high-gloss coatings also are well-suited for decorative projects, especially when color or color flakes are added.