Riyadh Sands and their Effect on Concrete Performance

A physical and geological study of Riydh sands was made on samples collected from crushing plants located in quarrying sites around Riyadh. An experimental study, following ASTM Standards, of the effects of these properties on the performance of fresh and hardened concrete was also carried out.Petrographic analysis showed that the fine aggregate particles are hard and in general subangular to subrounded and more elongated than spherical in shape. A large number of samples showed a presence of very fine sand and silt in them. The aggregates basically are classified as limestone rocks of various types. A rare occurrence of dolomitic limestone was discovered in one sample.Mineralogical analysis showed a presence of trace amounts of clay minerals in some samples of which a few had montmorillonite. Non-clay minerals present included calcite, silica. quartz. feldspar, limonite, iron oxide, hematite and gypsum in two samples in rare amount