Classifications

• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
  • E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
  • E04B1/62—Insulation or other protection; Elements or use of specified material therefor
  • E04B1/70—Drying or keeping dry, e.g. by air vents
  • E04B1/7007—Drying or keeping dry, e.g. by air vents by using electricity, e.g. electro-osmosis

Definitions

• the invention relates to a method for desalination, drainage and keeping masonry dry. This is often a necessary prerequisite for the complete renovation of old buildings in which water rises from the ground, which transports soluble salts into the masonry and accumulates in the evaporation zone.
• DD-PS 200 398 proposes combining active electroosmotic drying with prior desalination of the masonry.
• this invention has the disadvantage that corrosion-resistant electrodes made of graphite or platinized titanium are used. For their To enable reuse, it is proposed to replace these expensive electrodes with cheaper ones after desalting, but it has been found that the electrodes are subject to severe corrosion even after desalting. With electrodes made of iron, their volume increases many times as a result of the anodic oxidation, as a result of which the electrodes can be pressed out of the masonry and the electrokinetic permanent lock can be interrupted.
• DE-OS 3430449 and 3430450 only anodic chloride hydrates can be removed from the masonry.
• Adaptation to the moisture content in the masonry is desirable in order to prevent the masonry from drying out before the end of the desalination process and interrupting the desalination process.
• the aim of the invention is a method with which masonry in which water rises can be desalinated and drained in a simple manner and can be kept permanently dry.
• the invention has for its object to find a method with which moisture-damaged masonry with any moisture and salt content first desalted, then drained and then kept dry without the electrodes having to be replaced and without this process being interrupted by premature drying out or by the salts and iron oxides deposited on the electrode.
• this object is achieved in that one or more mortar bridges are placed between the electrodes arranged in or on the masonry, preferably made of iron, and the masonry depending on the measured moisture and salt content of the masonry Connect the masonry, but so that there is enough space between the electrodes and the masonry to absorb the soluble salts and iron oxides deposited on the electrodes.
• the invention is based inter alia on the knowledge that the direction of the water flow in the masonry is determined exclusively by the sign of the zeta potential. This results from the formation of a double layer of electrically charged ions at the phase boundary between solid and liquid. The charge carriers in the immediate vicinity of the solid are compensated for by ions that are in a rigid and a diffuse double layer. The potential measured at the boundary between the rigid and diffuse double layer is called the zeta potential. Its sign and size depend on the one hand on the structure and chemical composition of the solid, i.e. the masonry, and on the other hand on the properties of the adjacent liquid.
• Negative zeta potentials are very likely to be found in brick masonry.
• the electrodes arranged in or on the masonry are switched as an anode, the earth electrodes as cathodes.
• additives are added to the mortar according to the invention which keep the zeta potential small and prevent premature electrokinetic outflow of the water from the anode compartment.
• additives can be calcium or barium salts. This effect can be further enhanced according to the invention by admixing cationic surfactants, such as cetyltrimethylammonium bromide, because they reverse the sign of the zeta potential and cause a weak water flow towards the anode, which promotes desalination.
• cationic surfactants such as cetyltrimethylammonium bromide
• the electrodes connected to the masonry via the mortar bridges are connected to each other in an electrically conductive manner, and the highest possible DC voltage is applied to a system of earth rods, taking occupational health and safety into account. This is maintained until the current has dropped to a constant limit and thus indicates that desalination is complete.
• the salts and iron oxides that have accumulated in the anode compartments are then removed mechanically and by rinsing with water, and then the anode compartments are neutralized with a solution of barium hydroxide. If necessary, damaged mortar bridges are replaced. Then a direct voltage is applied again, so that the electrodes now act as a permanent electrokinetic barrier against rising moisture.
• a building is to be renovated against rising damp, the masonry contains less than 8% water, 1 x 10 -4 mol / g chloride and little sulfate.
• liquid-impermeable channels are arranged between the mortar bridges, which drain the dripping salt solutions to the outside. After desalination, which is indicated by a decrease in the current to a constant value, After the voltage source has been disconnected, the salts and iron oxides that have accumulated in the anode compartment are removed, and then the anode compartment is neutralized with a solution of barium hydroxide. Then a direct voltage is applied again in order to prevent the water from rising again by means of an electrokinetic permanent lock.
• the following mortar composition is selected in percent by mass:
• a DC voltage of 5o V was applied for desalination and a DC voltage of 1o V for establishing the permanent electrokinetic barrier.

Landscapes

• Engineering & Computer Science (AREA)
• Architecture (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Water Supply & Treatment (AREA)
• Physics & Mathematics (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electromagnetism (AREA)
• Chemical & Material Sciences (AREA)
• Electrochemistry (AREA)
• Drying Of Solid Materials (AREA)
• Working Measures On Existing Buildindgs (AREA)
• Processing Of Solid Wastes (AREA)
• Prevention Of Electric Corrosion (AREA)
• Aftertreatments Of Artificial And Natural Stones (AREA)
• Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (3)

Family

ID=5575503

Family Applications (1)

Country Status (6)

Cited By (3)

Families Citing this family (1)

Family Cites Families (3)

• 1985
  • 1985-12-30 DD DD85285727A patent/DD246334B1/de not_active IP Right Cessation
• 1986
  • 1986-12-11 EP EP86117283A patent/EP0228001B1/fr not_active Expired - Lifetime
  • 1986-12-11 DE DE8686117283T patent/DE3668932D1/de not_active Expired - Fee Related
  • 1986-12-11 AT AT86117283T patent/ATE50306T1/de not_active IP Right Cessation
  • 1986-12-28 HU HU865491A patent/HUT49182A/hu unknown
• 1990
  • 1990-02-08 GR GR89400163T patent/GR3000149T3/el unknown

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