Abstract: A method and apparatus of measuring water percentages of a fine aggregate comprising the steps of prewetting the fine aggregate, containing the prewetted fine aggregate in an air-tightly closed container, applying a centrifugal force to said container over a predetermined period to remove a portion of a quantity of water deposited on the fine aggregate, and measuring the water content remaining in or on the fine aggregate after being subjected to the centrifugal force, and thus determining a percentage of water adhered to the fine aggregate and a percentage of water of the fine aggregate in which interstice thereof is saturated with water while a surface thereof is dry.

Abstract: A method and apparatus of measuring water percentages of a fine aggregate comprising the steps of prewetting the fine aggregate, containing the prewetted fine aggregate in an air-tightly closed container, applying a centrifugal force to said container over a predetermined period to remove a portion of a quantity of water deposited on the fine aggregate, and measuring the water content remaining in or on the fine aggregate after being subjected to the centrifugal force, and thus determining a percentage of water adhered to the fine aggregate and a percentage of water of the fine aggregate in which interstice thereof is saturated with water while a surface thereof is dry.

Abstract: The quantity of water on the surface of sand particles is reduced by applying an impact force, e.g. centrifugal force created by a rotating disc. The sand particles thus treated are especially suitable for preparing a green concrete compound or a cement mortar by mixing them with water, gravel and cement.

Abstract: A quantity of water deposited on sand particles is adjusted to a predetermined value by utilizing a method and apparatus disclosed having a hopper through which the sand particles to be treated are supplied. A velocity energy is imparted to the particles to project them in a predetermined direction, thereby causing the particles to collide against rotating drums. As a result of the collision, a portion of a quantity of water initially deposited on the particles is removed therefrom and transferred to the drums, which is thereafter separated from the drums by a centrifugal force created by rotation of the drums. A plurality of notches or slits may be formed to axially extend along the periphery of the drums so that the deposited water moving along the periphery will tend into contact with be separated therefrom when it comes to one of the notches or slits. An air jet stream passing through the respective slits to the outside will function to facilitate the water removal from the periphery of the drums.

Abstract: One of ingredients of green concrete are supplied to a rotary disc through a central tube by a pump or low pressure air and the other ingredient is supplied to the rotary disc from a hopper by a screw conveyor. These ingredients are mixed together on a rotary disc and then projected by centrifugal force.

Abstract: In the preparation of a cement paste about 30 to 76% of the total water is added to the cement to form a funicular state, capillary state or slurry state, and the resulting mixture is kneaded so as to reduce the coagulated lumps of cement. Then the remaining quantity of water is added and the composition or mixture is kneaded again. Sand and/or gravel may be incorporated after the firstly kneaded mixture. The resulting cement paste, mortar or green concrete exhibits a small percentage of bleeding water and products prepared therefrom have a high compression strength.

Abstract: The quantity of water on the surface of sand particles is reduced by applying an impact force, e.g. centrifugal force created by a rotating disc. The sand particles thus treated are especially suitable for preparing a green concrete compound or a cement mortar by mixing them with water, gravel and cement.

Abstract: A plurality of moulds each including a side frame and a hollow bed overlying the side frame are vertically stacked with sealing members interposed between the beds and the side frames for hermetically sealing the moulds. While the pressure in the moulds is being reduced a hydraulic substance such as cement is poured into the moulds. The poured hydraulic substance is heat cured to produce solid articles releasable from the moulds. An empty mould is added to one side of the stack while a mould containing the cured substance is removed from the other side of the stack. Alternatively, the process can be carried out according to a batch system. The moulds may be packed with aggregate, fittings or means for interconnecting the articles.

Abstract: A green concrete mortar is prepared by the steps of preparing a first composition in which water is uniformly deposited about the particles of sand, preparing a second composition consisting of a powder of cement, mixing together the first and second compositions, thus forming stable shells about the particles of the sand, the shells having substantially a constant ratio of water to cement, and adding water to the shelled sand and then kneading the resulting mixture. The green concrete mortar can be poured into a moulding frame prepacked with a coarse aggregate i.e. gravel. After incorporating gravel into the mortar, the resulting green concrete can be moulded or blasted. The green concrete can be readily conveyed to a working station for constructing tunnels, buildings or the like.

Abstract: A slurry shaped freshly mixed fluid compound such as paste or mortar and coarse or fine aggregate are conveyed under pressure through discrete conduits and then mixed together substantially immediately before blasting. The mixture is blasted through a nozzle against a body to be covered with concrete.

Abstract: A plurality of moulds each including a side frame and a hollow bed overlying the side frame are vertically stacked with sealing members interposed between the beds and the side frames for hermetically sealing the moulds. While the pressure in the moulds is being reduced a hydraulic substance such as cememt is poured into the moulds. The poured hydraulic substance is heat cured to produce solid articles releasable from the moulds. An empty mould is added to one side of the stack while a mould containing the cured substance is removed from the other side of the stack. Alternatively, the process can be carried out according to a batch system. The moulds may be packed with aggregate, fittings or means for interconnecting the articles.

Abstract: The weight of aggregate for preparing concrete and mortar is measured while the aggregate is immersed in water contained in a container. The water in the container is discharged and the water in the interstice in the aggregate is also removed. Thereafter the weight of the aggregate is measured again. These measured values of the aggregate are used to determine the quantity of water to be added to the aggregate when it is used to prepare concrete or mortar.

Abstract: The fluidity of a plastic fluid, cement mortar for example, is measured by passing the fluid through a flow passage packed with an aggregate for simulating an actual mould, measuring the flow pressure, and measuring the quantitative flow coefficient between the fluid and the flow passage. The pressure remaining in the passage after the fluid has been poured into the passage and after the flow speed has been decreased to zero or the pressure after a quantity of the fluid has been added to the passage and prior to the discharge of the fluid from the passage is measured to determine the relative shear stress yielding value. Thereafter, the fluid is caused to flow to determine again the relative shear stress yielding value, and the relative closure coefficient is determined by the difference between said two relative shear stress yielding values.

Abstract: Hydraulic cement or the like is poured into a closed mould under a reduced pressure condition to a level slightly higher than a predetermined level. Coarse aggregate and steel rods are prepacked in the mould. After pouring, the pressure in the mould is increased to atmospheric pressure or a higher pressure to force the hydraulic cement above the predetermined level back into the space below the level thus compacting the poured in hydraulic cement. A cushion device is provided for the pouring device. An overflow tank is connected to the mould to observe the level of the poured cement. The pressure in the overflow tank is also decreased during pouring and increased after pouring.

Abstract: Hydraulic cement or the like is poured into a closed mould under a reduced pressure condition to a level slightly higher than a predetermined level. Coarse aggregate and steel rods are prepacked in the mould. After pouring the pressure in the mould is increased to atmospheric pressure or a higher pressure to force the hydraulic cement above the predetermined level back into the space below the level thus compacting the poured in hydraulic cement. A cushion device is provided for the pouring device. An overflow tank is connected to the mould to observe the level of the poured cement. The pressure in the overflow tank is also decreased during pouring and increased after pouring.