Abstract: A water absorption property of a concrete surface of an actual structure is measured in situ for clarification and evaluation of causative factors and so forth related to densification of surface layer concrete. An apparatus for a water absorption test has a position-fixing device, a detecting device and a measuring device. A device for water absorption test having vent means is positionally fixed on the concrete surface by the position-fixing device, with use of negative pressure or a mechanical connection. The detecting device detects an amount of water held in a chamber, and results detected by the detecting device are input into the measuring device. A water absorption rate is measured by the detecting device and the measuring device. On the basis of the water absorption rate measured at predetermined elapsed time, identification or comparison of causative or evaluative factors related to densification of the surface layer concrete is carried out.

Abstract: A water absorption property of a concrete surface of an actual structure is measured in situ for clarification and evaluation of causative factors and so forth related to densification of surface layer concrete. An apparatus for a water absorption test has a position-fixing device, a detecting device and a measuring device. A device for water absorption test having vent means is positionally fixed on the concrete surface by the position-fixing device, with use of negative pressure or a mechanical connection. The detecting device detects an amount of water held in a chamber, and results detected by the detecting device are input into the measuring device. A water absorption rate is measured by the detecting device and the measuring device. On the basis of the water absorption rate measured at predetermined elapsed time, identification or comparison of causative or evaluative factors related to densification of the surface layer concrete is carried out.

Abstract: It is an object of the invention to provide a cement admixture that can form concrete having a sufficient self-healing capability and satisfactorily maintaining its self-healing capability for prolonged periods. The cement admixture of the invention contains an expanding material and an alumina-silicate with swelling properties. The cement admixture is combined with cement to form a cement composition. The cement composition is mixed with water and an aggregate to provide concrete with an excellent self-healing capability.

Abstract: It is an object of the invention to provide a cement admixture that can form concrete having a sufficient self-healing capability and satisfactorily maintaining its self-healing capability for prolonged periods. The cement admixture of the invention contains an expanding material and an alumina-silicate with swelling properties. The cement admixture is combined with cement to form a cement composition. The cement composition is mixed with water and an aggregate to provide concrete with an excellent self-healing capability.

Abstract: A code converter circuit in a digital transmission system in which two mutually-synchronized digital signals are transmitted through a pair of transmission paths is disclosed. The transmission paths are characterized by the possibility of the terminal-to-terminal correspondence between input and output sides of the transmission paths being reversed. The code converter circuit includes an encoder on the input side of the transmission paths and a decoder on the output side of the transmission paths. The encoder comprises a modulo-2 adder and a switching circuit for selectively switching the input digital signals or the adder output signals to the transmission paths. The decoder comprises a modulo-2 subtractor and a switching circuit for selectively switching the digital signals from the transmission paths or the subtractor output signals to reproduce the transmitted digital signals.