Abstract: To prevent breakage of a sealing device having a main sealing body installed within an annular installing groove (31) formed in one member (3) to slidably and concentrically contact with the other member (2) and a backup ring (12) arranged at a non-sealing space side of said main sealing body, a height (h1±?h1) of said backup ring (12) in a facing direction of a bottom surface (31a) of said installing groove (31) to the other member (2) is greater than a facing distance (L±?L) between the bottom surface (31a) and the other member (2), and said backup ring (12) has a cross-sectional shape which is symmetrical in a thickness direction thereof, and has an easily compressible part (12a) which can be compressed to the extent of the difference (x) between said height (h1±?h1) and said facing distance (L±?L).

Abstract: To prevent breakage of a sealing device having a main sealing body installed within an annular installing groove (31) formed in one member (3) to slidably and concentrically contact with the other member (2) and a backup ring (12) arranged at a non-sealing space side of said main sealing body, a height (h1±?h1) of said backup ring (12) in a facing direction of a bottom surface (31a) of said installing groove (31) to the other member (2) is greater than a facing distance (L±?L) between the bottom surface (31a) and the other member (2), and said backup ring (12) has a cross-sectional shape which is symmetrical in a thickness direction thereof, and has an easily compressible part (12a) which can be compressed to the extent of the difference (x) between said height (h1±?h1) and said facing distance (L±?L).

Abstract: A material for improving the surface appearance of cementitious mouldings comprises a polyalkylene oxide compound which is selected from polypropylene oxide adducts of either polyethylene glycol or polyethylene oxide-ethylene diamine adduct, polypropylene oxide chains being attached to all terminal groups. The material may be added to a cementitious composition as an admixture or applied to the surface of a moulding which has not yet hardened.

Abstract: A cement pumpability-enhancing additive which confers good pumpability on cementitious compositions such as concrete consists essentially of(a) polyethylene glycol;(b) diethylene glycol monobutyl ether and/or a derivative thereof;(c) polysaccharide; and(d) a thickening polymer selected from the group consisting of polyacrylic acid derivatives, polyacrylic amide derivatives, cellulose ethers, polyphenyl ethers and polyalkylene glycol fatty acid esters;the weight solids proportions of (a), (b), (c), and (d) in the additive being respectively 5-55%, 10-80%, 1-20% and 1-20%. The additive is preferably used with a cement dispersing agent.

Abstract: A cement pumpability-enhancing additive which comprises polyethylene glycol and diethylene glycol monobutyl ether and/or a derivative thereof, and optionally polysaccharide. The additive is especially useful for high-strength, high-flow concretes for use in construction.

Abstract: A method for applying a cementitious composition to a surface comprising1) adding to the cementitious compositiona) a set retarding agent;b) a cement quick-setting agent;c) a cement dispersing agent;d) a slow release dispersing agent, that hydrolyzes under alkaline conditions to form a dispersing agent; and2) applying the concrete to a surface while the concrete is fluid.