摘要:
New set-accelerating admixtures for hydraulic cement compositions are disclosed. These admixtures incorporate known set accelerators and certain low molecular weight glycols, e.g., glycerol and ethylene glycol, are found to be surprisingly effective in decreasing the initial set time of hydraulic cements, mortars, and concretes, and are advantageous as reduced-temperature set-accelerators. Preferred embodiments of the invention may also comprise a component selected from the group consisting of certain alkanolamines and mixtures thereof.
摘要:
A cement composition capable of inhibiting drying shrinkage and cracking resulting therefrom composed of cement and an alkyl or cycloalkyl carbamate, an alkylene dicarbamate, polyoxyalkylene dicarbamate or mixtures thereof.
摘要:
A method of reducing the surface voids and imperfections of molded cement structures by forming the cement composition with an admixture comprising a combination of Welan Gum and a water reducing agent.
摘要:
The present invention provides additives for hydraulic cement compositions, particularly masonry cements, which improve the water-repellancy, workability, and board life of said compositions. The additives of the invention comprise a water-insoluble, water-repelling acid, a set retarding composition, an emulsifier, and a polymer selected from the group consisting of polyvinyl alcohol, polyvinyl acetate, hydroxypropyl substituted polysaccharides, and mixtures thereof.
摘要:
An improved high-pressure roll press process for forming finish ground cement is disclosed and is achieved by treating the material entering the roll press with a small amount of a hydroxyl or alkoxyl compound selected from lignin, phenol or monopropylene glycol or mixtures thereof.
摘要:
This invention relates to a method of enhancing the later age strength of certain blended cements. Under the process of this invention, certain blended cements, in particular those made from cement clinkers containing at least 4% C.sub.4 AF, when mixed with up to 0.2% of a higher trialkanolamine exhibit a marked increase in 7 and 28-day compressive strengths. The blended cements of this invention contain between 5 and 80% fillers or clinker substitutes. The higher trialkanolamine strength enhancing additive may be admixed with the cement powder or may be interground with the cement clinker during finish milling.
摘要:
A cement admixture and cement composition containing said admixture comprising finely ground rice hull ash formed by slurry grinding of said ash to a volume medium particle diameter or up to 4 micrometers.
摘要:
Rare earth elements, added to the raw materials mixture fed to a cement kiln, produce cement compositions having increased early compressive strengths. Preparation of such cements requires less grinding of clinkers to achieve equivalent early strengths than similar compositions without the rare earth elements.