METHOD OF PROTECTING POROUS MATERIALS AGAINST MOISTURE PENETRATION Russian patent published in 2007 - IPC C04B41/45 E04B1/64 

FIELD: manufacture of building materials.

SUBSTANCE: invention is designed for damp-proofing, restoration of destroyed moisture protection during repair and restoration of materials, buildings, and constructions, including historical ones. The whole volume of material is impregnated with hydrophobizing solution at a specified depth while controlling impregnation depth and thereby prolonging lifetime of material owing to lack of process holes in material being impregnated. Penetration of moisture is prevented by introducing hydrophobizer into bulk of material with the aid of pressure created through ultrasonic vibrations in the first Fresnel zone, ultrasonic vibrations being characterized by pulse duration 1-100 μsec, pulsing rate 1-100 μsec, ultrasonic vibration frequency 20-300 kHz, and electrical voltage on converter 1 to 2000 v. A gap between mixture being impregnated and piezoelectric converter surface constitutes 1/4 length of ultrasonic wave in solution and additionally receives ultrasonic vibrations from opposite side of material. Ultrasonic vibration propagation time tuvp is measured in dry and completely impregnated material and control of time of material filling to a specified depth tx(H) is determined from formula characterizing dependence of this parameter on (i) calculated value of ultrasonic vibration propagation time in material being impregnated at the specified depth, (ii) ultrasonic vibration propagation time in dry material, (iii) filling depth of material with solution, and (iv) length of mixture filled with solution. Equation is provided for calculation of coefficient K taking into account maximum ultrasonic vibration propagation time in dry material; minimum ultrasonic vibration propagation time in dry material; maximum ultrasonic vibration propagation time in completely impregnated material; and minimum ultrasonic vibration propagation time in completely impregnated material. Calculated value of ultrasonic vibration propagation time through material being impregnated is compared with specified time value, with time value calculated according to proposed formula, time value corresponding to given impregnation depth. If time values coincide, impregnation operation is stopped, if not, operation is continued.

EFFECT: increased moisture protection degree.

1 tbl, 6 dwg