Preparation of Calcium Silicate-Vermiculite Composite Light Materials and Study on Their Pore Structures
In order to fit for the demand for lightweight new fireproof material in the electric power fire protection,calcium silicate bonded vermiculite lightweight material with bulk density of 538-859 kg/m3 was prepared by static hydrothermal autoclave reaction using calcium hydroxide and powder quartz as calcium and silicon raw materials,expanded vermiculite as aggregate and adding reinforced fiber.The effects of 20%-40%vermiculite addition and 1.0-4.0 MPa molding pressure on the bulk density and strength of the material were discussed.The results showed that the fine pore structure was developed in the binding phase mainly composed of tobermorite and xonotlite,and the pores between it and vermiculite lamellae created up to more than 60%porosity of the material.At the same time,the interspersed binding structure of the binding phase and the vermiculite made the material have higher strength.The tensile strength of sample with 30%vermiculite and molding pressure at 2.0 MPa was close to 40 MPa,and its thermal conductivity was only 0.209 W/(m·K)at the hot surface temperature of 1 000℃.The material had low shrinkage and low thermal conductivity at high temperature,which had potential applications in the field of electric fire prevention.
tobermoritexonotliteexfoliated vermiculitepore structurelight weight materialelectric fire prevention