Bituminous membranes

From the first introduction of plastic materials into the roof membrane in Japan and Europe as the sheet (single-ply membrane) or liquid systems, in the late 1950s, they have replaced the conventional hot-applied, built-up bituminous membrane. Single-ply membrane was introduced in USA only in the mid 1960s. 

The most commonly applied vapour retarder materials in lightweight envelope parts are polyethylene film and bituminous or aluminium kraftpaper. In flat membrane roofs, the bituminous membranes applied for water-tighmess are also used as a vapour retarder. A new... 

The term sheet and membrane tend to be interchangeable. By definition, a membrane refers to the finished built-up waterproofing layer comprising one or more prefabricated sheets. As such, a sheet becomes a membrane in a single-ply application and a modified bituminous membrane may have two sheets, base and cap. 

Polymer-modified bituminous membranes were developed in Europe in the mid- 1960s and have been in use in North America since 1975. The polymeric systems have varied from natural rubber to more complex synthetic systems sueh as block copolymers and polymer blends. Most common polymers used as modifiers are polyisobutylenes, polybutadienes, polyisopienes, styrene-butiene-monomer, styrene-butadiene-rubber, butyl rubber, ethylene-vinylaeetate (EVA), atactic polypropylene (APP) as well as natural rubber. Polymers, such as atactic polypropylene or styrene-butadiene-styiene (SBS), impart flexibility and elasticity, improve cohesive strength, resist flow at high temperatures, and toughness.1 1 They are the most widely used modifiers of bitumen-based roofing materials. 

Rodriguez, I., Dutt, O., Paroli, R. M., andMailva nam, N. P., Effect of Heat-Aging on the Thermal and Mechanical Properties of APP- and SBS-Modified Bituminous Membranes, Mater. Struct. 26 355-361 (1993)... 

Guide for design of built-up bituminous membrane waterproofing systems for building decks... 

Built-Up Roofing. Built-up roofing (BUR) is a continuous-membrane covering manufactured on-site from alternate layers of bitumen, bitumen-saturated or coated felts, or asphalt-impregnated glass mats and surfacings. These membranes are generally appHed with hot bitumens or cold apphed bituminous adhesives (qv). 

The greater portion of PVC is installed in the mechanically fastened roofing system a lesser portion is installed in fully adhered appHcations. Although PVC was once heavily used in ballasted roofing systems, there are only a small number installed in the 1990s. Fleece-back membrane is popular in the PVC constmction for both fully adhered appHcations as well as in appHcations where a separator sheet is needed. PVCs ate resistant to vafious weather conditions, bactefial growth, and industfial chemicals. These membranes ate chemically incompatible with bituminous materials. PVCs ate offered in a variety of colors. The physical characteristics of a PVC membrane have been described (15). 

Specialty Eaves Flashing Membranes. Specialty eaves flashing membranes are polymer-modified bituminous sheet materials that are used as underlayment to resist leakage of shingle roofs as a result of ice dams. These sheet materials contain an adhesive layer which is exposed by removing its protective sheet. Special eaves flashing membranes can also be useful in warmer climates where a similar backup of water can occur from an accumulation of pine needles and leaves. 

Bucheli, T. D., S. R. Mttller, A. Voegelin, and R. P. Schwarzenbach, Bituminous roof sealing membranes as major source of the herbicide (R,S)-mecoprop in roof runoff waters Potential contamination of groundwater and surface waters , Environ. Sci. Technol., 32, 3465-3471 (1998b). 

The membrane wall s life was estimated to be over 25 years. The process can handle a wide variety of solid feedstocks, including lignite, brown coal, subbituminous coal, bituminous coal, anthracite, and petroleum coke. This gasifier can handle different coal types and is relatively insensitive to the size, condition, or other physical properties of the raw coal. 

The waterproofing body underneath the mat may be a plastic membrane, a thin aluminium sheet, or a bituminous/ concrete bed. These mats may be loosely placed or may be glued at certain points on the sub-layer. When placed on the concrete or on the asphalt, point forces may be exerted by the underlying aggregate. In addition, during construction activities, falling of reinforcements and other objects may induce local damage in the mat and in the... 

Surface Barriers The application of an overlay of low-slump concrete, latex-modified concrete (EMC), high-density concrete, polymer concrete, or bituminous concrete with membrane on the existing concrete provides a barrier that impedes continued intrusion of chloride anions, moisture, and oxygen that are necessary for continued corrosion. These barrier systems may be used only after decontamination because corrosive agents get trapped in the concrete, leading to loss in its capacity to function properly. 

FIGURE 18.3 Conceptual block diagram of a PC power plant. Several subsystems where membranes are candidate technologies are shown in callout boxes. (Adapted from U.S. Department of Energy—National Energy Technology Laboratory, Cost and performance baseline for fossil energy plants, Volume 1 Bituminous coal and natural gas to electricity, Rev. 2, 2010, available from http //www.netl.doe.gov/... 

The addition of fibres takes place at the stage of mix production or directly after spraying the bitumen or the bituminous emulsion on the pavement s surface. The latter creates a stress-absorbing membrane to inhibit reflective cracking (Yeates 1994). 

Yeates C. 1994. An evaluation of the use of a fiber-reinforced membrane to inhibit reflecting cracking. Symposium on Performance and Durability of Bituminous Materials. Leeds, UK. 

The stress-absorbing membrane (SAM) technique is similar to the single surface dressing. The only differences are that the quantity of the bituminous material sprayed is higher and the bituminous binder is exclusively modified bitumen. 

Cold-process roofing n. A bituminous roofing membrane, which consists of layers of coated felts that have been bonded with cold-applied asphalt roof cement and surfaced with an emulsified or cutback asphalt roof coating. 

Membrane Curing. Spraying a bituminous seal on the surface of fresh concrete, to prevent moisture loss. Membrane Fitter. See dust sampling,... 

Oba, K., and Roller, A., Characterization of Polymer-Modified Bituminous Roofing Membranes Using Thermal Analysis, Mater. Struct., 28 596-603 (1995)... 

Most types of roofing materials are bituminous and synthetic (polymeric) roofing membranes. The most commonly used roofing and waterproofing membrane is made by combining asphalt or coal tar pitch (bitumen) with felts or mats, or fabrics of organic or inorganic fibers. 

The built-up roof membrane consists of bitumen, reinforced with roofing felts, and aggregates which protect the bitumen from the UV radiation and oxidation. Bituminous materials have been used since 3500 BC. Because of their waterproofing, preservative, and binder characteristics, they were utilized by the ancients for the construction of houses and roads. " Bituminous materials were also used by ancient civilizations such as Egyptians for construction, mummification, waterproofing, preservatives, and binders. 

Concrete structures lying in waterlogged ground should be protected with sealing membranes (e.g. a high buUd bituminous composition on top of primer). 

This test method is under the jurisdiction of ASTM Committee D-g on Roofing, Waterproofing, and Bituminous Materials and is the direct responsibility of Subcommittee D08.03 on Surfacing and Bituminous Materials for Membrane Waterproofing and Builtup Roofing. 

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