Лако-красочные материалы — производство

7.1 Bearings and expansion joints for bridges Perhaps the most well known application of resins in civil engineering is in the form of resin mortar for either bridge bearings or expansion joint nosings. In bearings the mortar is used as a bedding compound on which to seat rubber or steel bearing pads. These pads serve […]

Apart from the use of resin adhesives to effect repairs to failed brick slips, perhaps the three most common applications in the repair and/or strengthening of masonry structures involve injection, the fixing of dowels and the use of bedding mortars. Resin injection is often used to stabilise deteriorating brickwork in listed structures. It involves drilling […]

There are two basic steps involved in the repair of a timber member. The first is to remove the reason for deterioration, for example by eradicating beetle attack or preventing the water penetration causing dry rot. The second is to select an appropriate repair technique and among the options available is the replacement of defective […]

Despite the extensive use of adhesives to bond structural metal in both the aircraft and vehicle industries for many years their use in civil engineering has been relatively rare. Early writers believed that resin adhesives could eventually replace welding in secondary connections in structural steelwork(22). For example, welding stiffeners to girder webs or diaphragms to […]

The advantages of externally bonded reinforcement over other methods of strengthening concrete structures include the ability to strengthen part of a structure whilst it is still in use, minimum effect on headroom, low cost and ease of maintenance (see Fig. 6.8, for example). The method has been in use for over 20 years, mainly to […]

Unless a portion of the original concrete is removed and replaced with a higher strength material, then a concrete overlay will usually result in an increase in member self weight. Applications at ground level are therefore more common than in suspended beams or slabs, although the use of polymer modified concrete overlays has found some […]

It is sometimes necessary to enhance the serviceability performance or ultimate load-carrying capacity of certain structural members in existing concrete structures. This might include the control of cracking in reinforced concrete beams and slabs under the action of superimposed loads, or a need to increase the reinforcement due to design deficiencies or construction errors. Increases […]

For the surface screeds and coatings applied for purely cosmetic purposes the repair will have little influence on the overall structural performance of the repaired member. However, with maintenance programmes now being formulated to provide the longest possible life before major renovation becomes necessary it is likely that patch repairs when they are carried out […]

In general a coating in the context of concrete repair can be considered as a fluid applied to the surface which forms a continuous film. In so doing the coating must be capable of adhering effectively to the concrete substrate. The main purposes of using coatings on concrete, apart from reasons of appearance, are to […]

Spalling of the surface layers of concrete in reinforced members may occur as a result of reinforcement corrosion (Fig. 6.1), the effects of fire or due to impact. Where the spalling is local and the cover is more than 25-30 mm, conventional sand-cement mortars based on high quality sands and applied using good rendering practice […]