Abstract: Concrete compositions including a binder, water, a fine aggregate, a coarse aggregate and an admixture are provided. The binder is formed with a blast-furnace slag composition including 100 mass parts of a mixture of 80-95 mass % of blast-furnace slag fine particles with fineness 3000-13000 cm2/g and 5-20 mass parts of gypsum for a total of 100 mass % and 0.5-1.5 mass parts or 5-45 mass parts of an alkaline stimulant. Such concrete compositions can maintain superior operability by reducing the discharged amount of carbon dioxide and the decrease with time in fluidity and air content of the prepared concrete compositions. They can also reduce the drying shrinkage of the obtained hardened objects and allow the obtained hardened objects to manifest necessary strength.

Abstract: The present invention provides a defect detecting/degree-of-filling-in measuring apparatus for concrete during placement that meets the tolerance for butting angle for the electrode with respect to the concrete form, and that is capable of carrying out measurement with the measurement depth being changed.

Abstract: Ultrafine powder is stored in a pneumatic transportation tank (20), and is discharged to a transporting conduit (23) while being fluidized by the pressurized air fed through a fluidizing air port (24). The ultrafine powder is fed to a weigher (30) provided at the other end of the transporting conduit (23), at which the weight of the transported ultrafine powder is weighed by a load cell (31). After the weighed value reaches 90% of a predetermined value, the fed amount of the pneumatic transportation air is reduced, and a bypass regulating valve (38) is adjusted to thus decelerate the transportation. When the weighed value reaches 100% of the predetermined value, the discharge of the ultrafine powder to the transporting conduit (23) is stopped. This method and the apparatus enable the storage, quantitative batch transportation, and automatic weighing of the ultrafine powder such as silica fume.