One of the most undesirable surface defects that can affect the finish of a concrete slab is the condition known as dusting. This is a problem that is universally distressing to owners, builders, architects, and contractors. The following trouble shooting guide list some of the common causes of dusting with corresponding preventive measures for each. Cause: excess of clay of silt in concrete. These harmful fines mix with the cement at the surface and result in dusting. Preventive measure: use of clean, well-graded aggregates. Cause: carbon dioxide from open salamanders or power buggy or mixer engines. When this gas comes in to contact with the surface of plastic concrete, a reaction occurs that impairs proper hydration. Preventive measure: vent salamander fumes to the outside. Provide sufficient ventilation. Cause: dry heat from winter protection heater can lower the relative humidity around the concrete too much. Concentration of heat on freshly placed concrete inhibits proper hydration of the cement, and results in weak concrete and a dusting surface. Preventive measure: water jackets should be placed on heaters to increase the relative humidity through evaporation. Any one of the acceptable methods of moist-curing should be employed. Also, location of heaters should be changed periodically to prevent all areas form extreme of harmful concentration of heat. Finally, cause: no curing or inadequate curing. Preventive measure: proper curing of concrete for the specified length of time is essential. Concrete that is not correctly cured will often be weak and the surface easily and quickly worn by foot traffic.