Curable compositions are provided comprising: a) an isocyanate-functional component and b) an amine-functional component comprising i) a primary amine- and/or a secondary amine-functional compound, and ii) a tertiary amine-functional compound. The tertiary amine-functional compound is present in the amine-functional component b) in an amount of 3.5 to 7 percent by weight, based on the total weight of amine-functional compounds in the amine-functional component b). Also provided are curable compositions comprising the above and c) untreated silica particles. The untreated silica particles are present in the curable composition in an amount of 0.5 to 15 percent by weight, based on the total weight of solids in the curable composition. Additionally provided are coated articles and polyurea articles formed from the curable compositions above.