One way to maximize the life expectancy and reduce the maintenance needs of an industrial concrete floor is to treat the surface with a metallic-aggregate dry-shake hardener. Designed to absorb single-point impacts and distribute them over a larger area, metallic-aggregate dry shakes help prevent surface fracturing and spalling. They also densify floor surfaces to prevent dusting and improve resistance to water, oil, and chemical spills. Manufacturers of metallic-aggregate dry shakes say treated floors can last up to eight times longer than plain concrete floors. Surface compressive strengths at 28 days are as high as 12,000 psi. But as with any concrete surface treatment, metallic-aggregate dry shakes must be applied according to recommended procedures to ensure good performance. Metallic-aggregate dry-shake hardeners come in two forms - premixed or job mixed. Some premixed iron-aggregate dry shakes are formulated for special applications: colored, static-disseminating, light-reflective, nonoxidizing, and flat-floor dry shakes. Before treating floors with metallic-aggregate dry shakes, the contractor, engineer, concrete supplier, and dry-shake supplier should determine: * How much shake to use (specified application rate) * How to apply the shake (by hand or mechanical spreader) * How to verify to amount of material used