| 摘要 |
<p>METHOD AND COMPOSITION FOR CONTROLLING VOLUME CHANGE IN FAST SETTING, FLUID IMPERMEABLE CEMENTITIOUS SYSTEMS A cementitious composition which, when mixed with water, is capable of setting rapidly into a hard mass of high compressive strength without substantial shrinkage during setting can be provided with reduced wet and dry volume changes in the hardened state while nevertheless possessing a high degree of impermeability to fluids,and abrasion, erosion and chemical resistance and similar characteristics desired in a composition having commercial usefulness in the construction industry through the provision of a cementitious composition comprising a mixture of aluminous cement, gypsum, a drying shrinkage inhibitor and a wet expansion inhibitor. The wet expansion inhibitor is lithium salt which may be added in an effective amount ranging between .01 to 15 percent, by weight, based on the aluminous cement and gypsum and preferably between .1 and .3 percent. It is preferred to employ between 60 and 90 percent, by weight, aluminous cement and between 10 and 40 percent, by weight, gypsum. The hardened drying shrinkage inhibitor, preferably Portland cement, is added in an amount ranging between .1 and 25 percent, by weight, based on the aluminous cement and gypsum, and preferably between 1 and 20 percent. Additional components, such as viscosity controllers, surface active agents, retarders, accelerators, gas generating or gas relaasing agents, fly ash, plasticizers, pumping aids, water retentivity aids, fillers, and aggregates may be utilized.</p> |
