Detecting deleterious fine particles in concrete aggregates and defining their impact.

摘要: This study examined the types of microfines in aggregates found northern Wisconsin and their influence on concrete prepared according to Department Transportation (WisDOT) specifications. Aggregates were collected from 28 sources 69 percent contain clay particles known be deleterious concrete. Seven selected for detailed evaluation including performance. The evaluated by x-ray diffraction thermal gravimetric analysis. Concrete performance testing included strength, shrinkage, porosity rapid chloride ion penetrability subject standard wet curing dry curing. A field test microfine identification was attempted but unsuitable conditions potentially useful laboratory with further development. results this research suggest current P200 threshold naturally occurring associated coarse fine WisDOT Standard Specification acceptable when are optimal meet typical ASTM requirements. When present aggregates, if air entrainment, uncontrolled water additions, certain intentional or unintentional chemical not carefully monitored controlled, then can do cause impacts.