Cellular foamed material and method for the manufacture thereof

Abstract

Abstract A METHOD FOR CONTINUOUSLY PRODUCING FOAMED CEMENTBASED CELLULAR MATERIAL BY SUBNECTING SPECIFIC LIQUID AND SOLID COMPONENTS TO HIGH-SHEAR MIXING FOR VERY SHORT PERIODS OF TIME AND THEN DISCHARGING THE MIXTURE SO THAT IT CAN FOAM AND SET PROMPTLY. THE LIQUID MATERIAL WHICH IS MIXED CONSISTS PRINCIPALLY OF WATER, AND PREFERABLY HAS A VISCOSITY OF LESS THAN ABOUT 2.5 CENTIPOISES. THE SOLID COMPONENT WHICH IS MIXED CONTAINS A PARTICULATE WATERSETTABLE (HYDRAULIC) CEMENT AND AN INERT PARTICULATE LAMELLAR FOAM STABILIZING AGENT. A GAS-FORMING AGENT WILL ALSO BE INCLUDED AS PART OF EITHER OR BOTH OF THE LIQUID AND SOLID COMPONENTS. THE TIME OF MIXING IS NOT GREATER THAN ABOUT FOUR SECONDS AND PREFERABLY LESS THAN ABOUT ONE SECOND, AND THE HIGH-SHEER MIXING PREFERABLY PROVIDES A MAXIMUM NOMINAL VELOCITY GRADIENT GREATER THAN ABOUT 500 SECONDS-1 FOR SUBSTANTIALLY ALL OF THE MATERIAL. THE MAXIMUM NOMINAL VELOCITY GRADIENT IS DEFINED FOR THIS PURPOSE AS THE MAXIMUM VALUE OF THE RATIO OF RELATIVE SPEED OF TWO SURFACES OF THE MIXER BETWEEN WHICH SUBSTANTIALLY ALL OF THE MIXTURE IS PASSED, TO THE DISTANCE BETWEEN SAID TWO SURFACES. PREFERABLY THE MIXER COMPRISES A ROTOR DISPOSED ALONG THE AXIS OF THE TUBULAR CHAMBER INTO WHICH THE INGREDIENTS TO BE MIXED ARE CONTINUOUSLY FED, THE ROTOR COMPRISING HELICAL SCREW MEANS DISPOSED ALONG THE LENGTH OF THE ROTOR FOR MOVING THE MIXTURE THROUGH THE CHAMBER TO ITS OUTLET AND FOR PROVIDING AT LEAST PART OF THE MIXING ACTION, TOGETHER WITH MIXING PINS EXTENDING RADIALLY FROM THE AXIS OF THE ROTOR TO WITHIN A SMALL DISTANCE OF THE CHAMBER WALL TO EFFECT FURTHER MIXING ACTION. THE RESULTANT PRODUCT IS OF INCREASED COMPRESSIVE STRENGTH AND CHARACTERIZED BY THE FACT THAT SUBSTANTIALLY ALL OF THE PORE VOLUME THEREOF IS PROVIDED BY PORES HAVING EFFECTIVE DIAMETERS OUTSIDE A RANGE EXTENDING FROM ABOUT TWO MICRONS TO ABOUT 300 MICRONS, AND PREFERABLY AT LEAST ABOUT 97% OF THE PORE VOLUME IS PROVIDED BY PORES OUTSIDE SAID RANGE. THERE IS ALSO PROVIDED NOVEL CELLULAR PRODUCTS CONSISTING ESSENTIALLY OF HIGH ALUMINA CEMENT, AS THE WATER SETTABLE CEMENT, AND THE STATED INERT PARTICULATE LAMELLAR FOAM STABILIZING AGENT.

Inventors

• 👤 J Magder

Bibliographic Details