Pavers

Ba.lla.sted. A ballasted roof assembly consists of a membrane or membrane and substrate material (insulation, sHp sheet, etc) loosely laid over a deck with the assembly held in place using ballast. A minimum ballast weight of 48.9 kg/m or 10 pounds per square foot (PSF) is used. The ballast can consist of smooth rounded stone, cmshed stone (a separator sheet must be used between the cmshed stone and the membrane), or pavers (both standard and lightweight). Both stone and pavers come in a wide variety of colors. The membrane is affixed to the building only at the deck perimeter (roof edge) and at various penetrations. Wall and penetration flashings are typically fuUy adhered and sealed to prevent water entry into the roof assembly. The maximum slope a ballasted system should be installed over is 16.7 cm/m. 

Chemical resistance is normally achieved by synthetic resin toppings, polymer or resin-modified cementitious toppings or modular (tiled or paver) toppings. 

Paver MA, Russell CA, Wright DS (1995) Gallium, Indium and Thallium excluding Transition Metal Derivatives. In Abel EW, Stone FGA, Wilkinson G (eds) Comprehensive Organometallic Chemistry II. Elsevier, Oxford UK, vol 1, chap Up 503... 

Beswick MA, Kidd SJ, Paver MA, Raithby PR, Steiner A, Wright DS (1999) Inorg Chem Commun 2 162... 

Codicept, Paveral Cholestabyl, Cholestid Questran, Cuemid Acthar, Cortigel, Cortrophin... 

Concrete dampproofers are integral admixtures that alter the concrete surface so that it becomes water repellent, or less wettable . This is illustrated in Fig. 4.1, which shows a close up of a water drop on a surface of a concrete that has had a dampproofer incorporated into it. This water repellency conferred on the concrete is only effective in preventing water from entering the surface when the applied pressure is small, e.g. rainfall in windy conditions, or capillary rise. The latter effect is shown in Fig. 4.2. In view of this, these materials are used normally for improving the quality of concrete pavers, tiles, bricks, blocks and cladding panels where the additional benefits of reduced efflorescence, the maintenance of clean surfaces and the more even drying out of adjacent bricks and panels are also obtained. 

Fig. 7.3 Placing of a concrete sidewalk using a slip-form paver (courtesy, Barber Greene, USA).

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