Waterproofing

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Waterproofing

A coating or membrane applied to a surface, such as a foundation wall, to prevent the intrusion of water under pressure; materials may include asphalt, felt, tar, or various synthetic membranes.

Waterproofing

 

the protection of structural components, buildings, and installations from the penetration of water (antiseepage waterproofing) or of construction materials from the harmful effects of wetting or seepage water or other corrosive fluids (anticorrosion waterproofing). Waterproofing ensures the normal use of buildings, installations, and equipment and increases their reliability and durability.

Antiseepage waterproofing is used for protection against water penetration into underground and underwater structures (basements and underground areas of buildings, transportation tunnels, mine shafts, coffers, and caissons). In hydraulic engineering it is used for protection against water penetration of retaining structures (dams, their aprons, upstream paddle blankets, and core walls); in addition it is used for protection against the leakage of industrial-operation or waste waters (canals, tunnels and other water conduits, basins, settling tanks, and storage tanks).

Anticorrosion waterproofing is designed to protect construction materials from chemically corrosive liquids and waters (for example, mineralized ground waters, seawater, and industrial drainage waters), from the corrosive effects of the atmosphere (for example, in aboveground metallic structures and hydraulic engineering installations in zones of variable water level), and from the electrical corrosion caused by stray currents (for example, in transmission line supports, pipelines, and other underground metallic structures).

Waterproofing is differentiated according to its basic material as asphalt, mineral, plastic, and metallic; according to the method of its application as painted, plastered, glued, poured, impregnated, injected, filled, and installed; according to its principal purpose and structural characteristics as surface, keyed expansion-joint, “clamp” and “tear,” joint-and connection-caulking, and multipurpose (for example, in hydrothermal insulation and plastic compensators).

Painted waterproofing (hot and cold) is carried out in the form of a thin (to 2 mm) multilayered coating, usually of bituminous and polymer lacquers and paints, for the an-ticapillary and anticorrosion protection of reinforced-concrete and metallic structures. The most reliable materials are the hot bituminous polymer and cold epoxy resin coatings. Increasing use is being made of the new cold-setting polymeric materials.

Plastered waterproofing (hot and cold) consists of a multilayered (to 2 cm) coating. Cement gunite and cold and hot asphalt plaster mortars and mastics (which do not require protective enclosures and which permit mechanization of their application) are the most widely used for reinforced-concrete structures. Polymeric concrete and polymeric cement coatings and colloidal cement mixtures are also being used more extensively.

Glued waterproofing is carried out by gluing on the rolled roofing materials in the form of a multilayered (usually three or four layers) coating with necessary protection by surface fasteners and partitions. Despite its widespread use, glued waterproofing has been replaced in a number of instances by painted and plastered waterproofing. Glued waterproofing is characterized by a high resistance to cracking. Polymer films and fiberglass materials are being used for its improvement.

Poured waterproofing is the most reliable type of waterproofing; it is carried out, as a rule, by pouring hot asphalt mastics and mortars along the horizontal foundation (in two or three layers, with a total thickness of 20-25 mm) and behind the wall or wall casing (thickness, 30-50 mm). Because of its complexity and high cost, this method is used only where it is particularly critical. It is being developed by using asphalt claydite concrete, bituminous perlite, foam epoxides, and other foam plastics.

Filled waterproofing is carried out by pouring loose waterproofing materials into watertight layers and cavities (for example, into an enclosed casing). The method is analogous in design and purpose to poured waterproofing, but it has a greater thickness (to 50 cm) and is used for both combined heat insulation and waterproofing (water-repellent granules, powders, and asphal’toizol) in cases of low water impermeability.

Impregnated waterproofing is carried out by impregnating structural products made of porous materials (concrete slabs and blocks, asbestos cement sheets and pipes, and blocks made of limestone and tuff) with an organic binding agent (bitumen, coal tar pitch, petrolatum, and polymer lacquers). Impregnated waterproofing is most reliable for precast elements that are subjected to intensive mechanical effects (piles, pipes, tubing, and foundation blocks).

Injected waterproofing is carried out by forcing a binding material into the joints and cracks of structural components or into the ground adjacent to them by methods that are analogous to those used in the installation of antiseepage screens. It is utilized, as a rule, in the repair of waterproofing. New polymers, such as urea and furan resins, are being used more and more extensively in its installation.

Installed waterproofing is carried out with specially manufactured elements (metallic and plastic sheets and molding strips), which are fastened to the main structure by means of mounting braces. This method is utilized in especially complex cases. It is being improved by the use of fiberglass materials and rigid polyvinyl chloride and by the industrial production of precast reinforced-concrete components, which are coated under plant conditions by means of painted or plastered waterproofing.

The most widespread structural type of waterproofing consists of surface coatings in combination with the sealing of deformation or structural joints and the installation of coupled elements that ensure the continuity of the entire pressure front of the structure. Surface waterproofing materials are designed such that they are squeezed by water pressure up against the waterproofed supporting structure. New types of structural waterproofing have also been developed that operate on the “tear” principle.

The sealing of deformation joints is of essential importance in waterproofing a structure. This process is carried out in order to make the joints impermeable to water and to protect them from obstruction by soil, ice, and floating objects. In addition to water impermeability these seals must also possess a high degree of flexibility, so that they can freely follow the deformations of the joined elements or sections of the structure. The most widespread types of seals are asphalt keys and liners, metal core walls and expansion pieces, rubber and plastic core walls and liners, and distillate hermetic materials. Also envisaged is the extensive utilization of bituminous polymeric hermetic materials, fiberglass-reinforced plastics, and fiberglass rubber, which allow simpler and more reliable seals to be made.

Waterproofing that operates on the “tear” principle is carried out in the form of coatings applied to the structure to be protected from the side opposite that of the water pressure. This method is employed, for the most part, in the repair and restoration of the waterproofing of structures (for example, by plastering from within of basements that are subject to flooding) and for the antiseepage protection of underground structures whose supporting elements are concreted in butt joints to the surrounding ground or rock foundation (tunnels, caissons, and underground compartments at great depth). In order to install waterproofing of this type, waterproofing coatings are used that allow anchoring behind the main structure (poured and installed waterproofing) or that have a high degree of adhesion to concrete under the prolonged effects of water (cement gunite, cold asphalt, and epoxy painted waterproofing).

The complex of operations involved in installing waterproofing includes preparation of the foundation, installation of the waterproofing covering and protective enclosure, and sealing of the deformation joints and the coupling sections. In selecting the type of waterproofing to be used, preference is given to those coatings which, under conditions of equal reliability and costs, allow the overall mechanization of the waterproofing operations and the elimination of their seasonal character. In the USSR new types of waterproofing installations have been developed that successfully resolve these problems, including asphalt plastered, polymer painted, impregnated, and installed waterproofing.

REFERENCES

Popchenko, S. N., and M. G. Staritskii. Asfal’tovye gidroizoliatsii betonnykh i zhelezobetonnykh sooruzhenii. Moscow-Leningrad, 1962.
Noskov, S. K. Ustroistvo gidroizoliatsii v promyshlennom stroitel’stve. Moscow, 1963.
Stroite’nye normy i pravila, part 3, section C, chapter 9: “Gidroizoliatsiia i paroizoliatsiia.” Moscow, 1964.
Nechaev, G. A., and E. D. Fedotov. Primenenie plastiche skikhmass dlia gidroizoliatsii zdanii. Leningrad-Moscow, 1965.
Ukazaniia po proektirovaniiu gidroizoliatsii podzemnykh chasteizdanii i sooruzhenii: SN 301-65. Moscow, 1965.
Bovin, G. P. Vozvedénie vodonepronitsaemykh sooruzhenii iz betona i zhelezobetona. Moscow, 1969.

G. P. BOVIN and S. N. POPCHENKO

waterproofing

waterproofing applied to masonry wall units
A material, usually a membrane or applied compound, used to make a surface impervious to water.