Abstract
This study is carried out to clarify the influence of particleshape of fine aggregate to the properties of mortar in dam concrete. We use 8 kinds of fine aggregates. One of them is produced by cone crusher, three of them by Los Angeles machine with ceramic balls, one of them by rod mill and three of them by Barmax. Solid volume percentage for shape determination of the used fine aggregate ranges from 53.1% to 59.2%. In this experiment, moderate heat portland cement blended with 30% fly ash is used. This kind of cement is usually used in darn concrete. The ratio of fine aggregate to cementaneous material is 2 to 1, and Water to cementaneous material ranges from 0.33 to 0.48. The flow value, bleeding ratio and compressive strength of mortar are measured. The surface of the particle is observed by electron microscope. The surfaces of crushed sand stone and river sand are also observed to compare with granite aggregate.
Results indicate that increase of solid volume percentage for shape determination by 1% has an equivalent effect of the increase of flow value by 10 mm. This means that the water content can be reduced by 4 to 5 kg/m‹SUP›3‹/SUP›.
