Abstract: A cement retarder is provided which comprises 5 to 20% by weight, based on the weight of said retarder, of gluconic acid and/or tartaric acid and/or a water soluble salt thereof, 30 to 10% by weight, based on the weight of said retarder, of citric acid and/or an alkali salt thereof, and 50 to 85% by weight, based on the weight of said retarder, of an alkali carbonate. A rapid hardening cement is also provided which contains the above cement retarder.

Abstract: A concrete composition for making concrete moldings of high strength is provided which comprises 400-600 kg. of Portland cement per unit m.sup.3 of concrete, 3-30% by weight of insoluble (Type II) anhydrous calcium sulfate and 0.1-3% by weight of cement dispersing agent. A method for making concrete moldings of high strength having the above components are also provided which comprises subjecting to pre-steaming and then steam curing under atmospheric pressure. According to the present invention, concrete moldings having both high compressive strength and pre-stress with reduced relaxation can be obtained only in a day without subjecting to autoclave curing.

Abstract: A process for preparing amino alcohols, which comprises reacting a polyhydric alcohol containing at least one primary alcoholic hydroxyl group and at least one secondary alcoholic hydroxyl group and expressed by the following general formula ##STR1## wherein R.sup.1 is an alkyl group, R.sup.2 and R.sup.3 are identical or different and represent a hydrogen atom or a lower alkyl group an n is an integer of 0 to 3,With ammonia in the presence of specified hydrogenation catalyst thereby to aminate the secondary alcoholic hydroxyl group of the polyhydric alcohol selectively.

Abstract: Novel substituted hydrazide derivatives of 7-(substituted)amino-3-methylene-cepham-4-carboxylic acids expressed by the formula ##STR1## wherein R.sub.1 represents alkyl containing at least 3 carbon atoms, cycloalkyl, or optionally substituted aryl, and one of R.sub.2 and R.sub.3 represents hydrogen with the other being hydrogen or the same as R.sub.1 ; or R.sub.1 and R.sub.2 form a heterocyclic ring optionally through a hetero atom together with the attached nitrogen and R.sub.3 represents hydrogen atom; and Z.sub.1 represents amino or protected amino; and acid addition salts thereof, which are useful as intermediates for synthesizing cephalosporin antibiotics.

Abstract: A process for racemizing optically active amino compounds, which comprises contacting an optically active compound of the general formula ##STR1## wherein R.sub.1 is an alkyl, cycloalkyl, substituted or unsubstituted phenyl, or non-aromatic heterocyclic group, and R.sub.2 is a hydrogen atom or an alkyl or substituted or unsubstituted phenyl group,With ammonia and hydrogen in the presence of a hydrogenation catalyst.

Abstract: A quick hardening cement-asphalt composition used as a grout for a ballast-filled track structure comprising(a) 100 parts by weight of a cement composition prepared by adding to portland cement about 10 to 50% by weight of a mixture of a calcium aluminate-series mineral and calcium sulfate in a weight ratio of about 1:0.3 to 1:3; about 0.05 to 10% by weight of an inorganic salt, and about 0.05 to 3% by weight of at least one of an organic carboxylic acid, an organic hydroxycarboxylic acid and a salt thereof, and(b) about 30 to 400 parts by weight of an asphalt emulsion containing about 0.2 to 8% by weight of a polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, sorbitan alkyl ester, polyoxyethylene sorbitan alkyl ester or sucrose fatty acid ester nonionic emulsifier and about 0.05 to 2% by weight of a multivalent metal chloride, calculated as the multivalent metal ion.

Abstract: A method for working quick hardening cements comprising preparing (A) a composition comprising a cement paste, mortar or concrete and (B) a composition comprising a powder or suspension composition of calcium aluminate and inorganic sulfate, mixing the composition (A) and the composition (B) and quickly executing the mixture immediately after the admixture.

Abstract: A process for preparing a mixture of organic carboxylic acids and esters thereof consisting predominantly of epsilon-hydroxycaproic acid, adipic acid, formylvaleric acid, and esters of these acids by oxidizing a mixture of cyclohexane, cyclohexanol and cyclohexanone with molecular oxygen, which comprises withdrawing at least a part of the oxidation reaction mixture from the oxidation reaction system, extracting the organic carboxylic acids and esters thereof from the oxidation reaction mixture until the concentration of the total carboxyl groups of said oxidation reaction mixture is reduced to a value not greater than 1.

Abstract: A method for working quick hardening cements comprising preparing (A) a composition comprising a cement paste, mortar or concrete and (B) a composition comprising a powder or suspension composition of calcium aluminate and inorganic sulfate, mixing the composition (A) and the composition (B) and quickly executing the mixture immediately after the admixture.

Abstract: A fire retardant thermosetting resin composition containing tricalcium aluminate hexahydrate as a filler.