Лако-красочные материалы — производство

The injection of resin-based materials into cracked concrete is a technique widely employed to either restore structural integrity or to seal the cracks for subsequent durability. However, a necessary preliminary to the consideration of resin injection is an assessment to establish the cause of cracking in the first place. Here it is important to distinguish […]

6.1 Concrete repair The 1950s and 1960s saw an enormous growth in new construction and many faults are now becoming evident in some of the structures constructed during these years of peak activity. Today, repair and refurbishment is often preferred to demolition and reconstruction with the result that the maintenance and refurbishment market now represents […]

No discourse on the specification and use of adhesive materials would be complete without referring to safe handling precautions. Safety aspects should partner the measures practised within a quality system, and they represent a vital part of the education and training of the personnel involved. The history of adhesive bonding has shown that accident and […]

Tests to monitor the quality of the adhesive materials may relate to the fresh state (e. g. viscosity, sag, pot-life), and to the hardened state — requiring the measurement of mechanical properties. Quality variations in the cured adhesive layer itself can occur as a result of a number of factors. Voids may be present due […]

The measurement of the strength of adhesion between adherend and adhesive requires a measurement of the intermolecular forces of attraction; this is not currently possible. This aspect of quality control is therefore essentially reduced to assessing the adherend surface characteristics prior to bonding, although some post-bonding simple mechanical tests are appropriate. Weak or loose surface […]

Appropriate test methods for the control of fabrication procedures and non-destructive testing (NDT) are basic requirements for the formation of structural adhesive joints. Such methods should be based upon relatively easily measurable parameters that have a close identity with the properties of the bonded assembly that need to be controlled. However the quality of bonded […]

Probably the most critical aspect of the introduction of a new process is that of the education and training of the personnel involved. It is vital that the people have a qualitatively correct overall picture of the importance of the different stages of the bonding operation, and of the health and safety considerations. The use […]

The design of bonded joints must take into account the nature and magnitude of the likely operating stresses and strains, and should be contrived so that unacceptable peel or cleavage forces are not introduced into the bondline. Such design should also allow for changes in the mechanical properties of adhesives which may take place under […]

It has been emphasised that the achievement of a high standard of surface pretreatment is the key to maximising joint durability and joint quality. Unfortunately, in the practice of adhesive bonding for applications in construction, surface pretreatment is likely to be the most difficult process to control. The choice and specification of pretreatment procedures should […]

There exist a number of sources listing the general factors involved in adhesive selection and the performance properties to consider (e. g. 2-5). It has already been emphasised that the adhesive represents only one part in a joining process which involves, among other things, a consideration of the needs of the various materials in the […]