EP1327033B1 - A method for the removal of dampness from buildings by the cristalline injection technique - Google Patents

Abstract

A method for the removal of dampness from buildings, the walls of which became damp because of capillary rise of groundwater, by the crystalline injection method, wherein into purposely drilled holes in the wall, made preferably at the same level from 10 to 18 cm apart at an angle of 15 to 30 degrees previously soaked with water, upon their previous additional soaking with water, is introduced a mixture of aqueous suspension of portland cement, a silicone activator with sodium siliconate and sodium orthophenylphenolate and water taken in a quantity such that the mixture have a homogenous, liquid consistency and is self-levelling in the vessel so that during its gravitational introducing into the injection holes no air plugs could form.

Description

The subject of the invention is a method for the removal of dampness from the walls of masonry buildings which became damp as a result of capillary rise of groundwater in the wall material, which consists in injecting of an aqueous mixture into a number of holes drilled in a building partition to be treated, the mixture includes portland cement and specially developed inorganic and organic silicate activators with an addition of an agent that controls the unfavourable convection effects in the capillary liquids which disturb the desirable process of self-organisation of crystals. The ionic components of this injection mixture, in diffusing inside the water-filled capillaries of the masonry wall material, produce a horizontal or vertical damp-proof insulation in the wall as a result of a specific crystallisation of some water-insoluble compounds, thereby sealing off the pores and capillaries in the zone of the purposely drilled injection holes. Additionally, to accelerate the diffusion processes, a surfactant is added into the injection preparation, which favourably reduces viscosity of the injection preparation, thus increases diffusion rate, which results in the desirable increase in the radius of penetration of the agents that build the damp-proofing barrier in walls.

Know in the art related to the techniques of the removal of dampness absorbed from ground by masonry walls are a number of modified techniques of the crystalline injection methods covered by Polish patents nos. 153 294 and 160 174 and the patent application P. 338937.

In particular, Polish patent No. 160 174 teaches a method for the removal of dampness in buildings, wherein a mixture of aqueous solutions of portland cement and an activator which is sodium metasilicate and/or sodium polysilicate with an addition of sodium phosphate is introduced into the drilled holes.

In the technique described in the former two patents the resultant penetration radiuses of the crystalline injectate are unsatisfactorily large, while the crystals self-organisation effect at high concentration gradients and at very low temperatures becomes disturbed at larger distances from the injection hole centres. The use of microwave generators, on the other hand, reduces diffusion rate and, in consequence, increases the penetration radius. However, it poses a great health hazard to the crew and the users of the buildings being treated. Also, the process of the heating ofthe injection zone on injecting the walls can easily get out of control.

Unexpectedly good effects were achieved upon addition of a surface-active agent into the injection preparation, as the radius of penetration of the damp-proofing agent that stops groundwater from rising up the masonry wall by the capillary rise effect. It was also found that the presence in the injection preparation of a hydrophobic compound such as potassium or sodium methylsiliconates and of a surfactant sodium ortho-phenylphenolate of fungicidal properties substantially reduces the disturbances of the crystals self-organisation mechanism which underlies the process of production of damp-proof insulation in walls. The insulation produced from domenes of crystals that are arranged in concentric spherical rings in space can be seen in a vertical or horizontal cross-section as a number of concentric rings of an increasingly greater radius. The performance of the barrier thus produced is of indefinite lifetime, irrespective of the initial moisture content and salinity in the walls, as the radius of penetration of the injection preparation according to the invention is the larger, the high initial moisture content in the wall. This property of the crystalline injection technique makes it different from all the other wall dampness removal techniques known in the art, as a greater wall moisture results there in a reduced penetration radius or in the need to resort to the expensive heat sources to pre-dry the wall prior to the injection operation.

The method according to this invention consists in a suitable preparation of the injection mixture, which includes portland cement, an activator in the form of sodium metasilicate and/or sodium polysilicate, sodium/potassium methylsiliconate, sodium orthophenylphenolate as a surfactant, and water, the ratio by weight of the components: cement to activator preferably ranging from 1:1 to 10:0.2, whereas the ratio of sodium metasilicate, potassium metyfsificonate and sodium orthophenylphenolate and water is preferably 1:0.2:0.05:4, respectively. Unexpectedly, the presence of sodium or potassium methylsiliconate and of sodium orthophenylphenolate proved to be favourable as concerns a clearly increased penetration radius for the injection mixture and rendered the insulation membrane more flexible even at low temperatures of the walls in wintertime, as compared with the treatment with the injection mixture without these additives. The penetration radius increased by ca. 25% .

The horizontal damp-proof insulation consist in first drilling in the wall from which dampness is to be removed holes arranged on a horizontal line parallel to the floor. The holes, 20 mm in diameter are drilled at an angle of 15-30 degrees every 12-16 cm to a depth equal to the wall thickness minus 5-10 cm. Additional water is poured into the holes thus made prior to the introduction of the injection preparation in a quantity at least equal to the volume of the holes but not more than 0.5 1 for the walls ca. two ceramic brick thick. The amount of the preparation introduced by gravity into the holes according to the invention is equivalent to the volume of the hole drilled. Upon termination of the injecting operation the holes are filled up with the same preparation and made level with the wall face using a spatula.

The damp-proofing barrier of the crystalline kind is attained within seven to ten days depending on diffusion rate which depends on temperature. The sealing effect of the preparation according to the invention consists in that the silicate ions dissolved in water along with calcium ions derived from specific dissociation of portlandite, the mineral present in portland cement, make water-insoluble calcium silicate to precipitate in the capillaries. A characteristic feature of the precipitated crystals is that their precipitation at the outer end of the capillary at the injection hole do not stop the precipitation reaction components to penetrate deeper into the capillary. This effect, which is unexpectedly beneficial from the technological viewpoint, is enhanced by the sealing function of the silicone compounds and the action of the fungicidal surfactant that accelerates the diffusion rate.

As shown by laboratory testing, during the dampness-removal treatment by the crystalline injection technique according to the invention, the crystallisation products become arranged unexpectedly about the injection hole in the form of concentric rings that are spaced initially several millimetres and then the distance between the rings gradually increase to reach about one centimetre at a distance of ca. 10 cm from the centre of the injection hole. The mechanism of the reaction proceeds initially through crystallisation to form very fine crystals in the whole bulk involved in the diffusion process, and subsequently through a spontaneous process referred to as self-organisation of crystals to produce crystalline domains as well as domains not containing crystals.

An explanation of this effect is a thermodynamic driving force that occurs in a homogeneous sol, admittedly being the result of a competitive growth of molecules on account of the dependence of the equilibrium constant on the radius of the molecule which is due to surface tension. As a result of this effect a number of images of the structures formed are obtained which resemble the Liesegang rings. The formation of the whole of the barrier in its thermodynamic mechanism reflects the so-called Prigoainian effects (the 4^th principle of thermodynamics) occurring irreversibly in states far from the thermodynamic equilibrium.

Claims (1)

1. A method for the removal of dampness from buildings, the walls of which became damp because of the capillary rise of groundwater, by means of crystalline injection wherein, into purposely drilled holes in the wall, made preferably at the same level, from 10 to 18 cm apart, at an angle of 15 to 30 degrees, previously soaked with water taken in a quantity equal to the hole volume, is injected a mixture of aqueous suspension of portland cement and an activator, which is sodium or potassium metasilicate, preferably at a cement to activator ratio by weight equaling from 1:1 to 10:0.2 with an addition of alkali metal siliconates and sodium orthophenylphenolate, taken preferably in the proportion: activator/ siliconate / orthophenylphenotate equal to 1:1:0.1, whereupon, following the injecting, to accelerate first the diffusion then the crystallization processes, the holes are stopped with a thicker injection preparation and, using a spatula, floated snugly with the wall face.