科研之友
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摘要
This paper surveys different material combinations and applications in the field of mineral-based strengthening of concrete structures. Focus is placed on mechanical behaviour on material and component levels in different cementitious composites; with the intention of systematically maping the applicable materials and material combinations for mineral-based strengthening. A comprehensive description of a particular strengthening system developed in Sweden and Denmark, denominated as Mineral-based Composites (MBCs), together with tests from composite material properties to structural elements is given. From tests and survey it can be concluded that the use of mineral-based strengthening system can be effectively used to increase the load bearing capacity of the strengthened structure. The paper concludes with suggestions on further development in the field of mineral-based strengthening. 1. Introduction The existing civil engineering infrastructure is a very important element of the economical potential of a majority of the countries worldwide. A large number of today＊s buildings, transportation systems, and utility facilities are built with reinforced concrete and many of these systems are currently reaching the end of their expected service life. Additionally, increased loads and traffic flows, reuse, and ongoing deterioration even affect the durability of structures that are less than 20 years old. There exist several repair and strengthening methods that can be applied to existing concrete structures for this purpose, such as cross section enlargement of critical elements, span shortening with additional supports, external/internal post tensioning, and steel plate bonding or strengthening with fibre-reinforced polymer (FRP) composites. Since the end of the 1980s, the use of FRP has been researched and applied increasingly for the rehabilitation of existing concrete structures. Externally epoxy-bonded FRP systems have been proven to be an effective strengthening method in repairing or strengthening structures and a large amount of literature is published on this topic; see, for example, [1每7]. FRP reinforcements can be used in numerous ways to strengthen a structure, For example, by bonding plates or sheets with a high-quality epoxy to the surface of concrete, timber, or even steel structures. There are also methods to wrap columns for enhanced ductility and strengthening systems where FRP rods are embedded in the concrete surface. Systems replacing the epoxy with polymer-modified mortars have been recently developed. For example, continuous fibre
