Concrete structures can often show cracks. Even though small cracks do not affect the structural properties of a structure, they can increase permeability which, in turn, reduces structural stability. This, in particular, in humid environments, can threaten structural durability. Concrete structures based in humid environments, like concrete dams or spillways, are more susceptible to cracking. Concrete repair is a complicated process and differs from other concrete structure construction technologies. Concrete repair requires that new materials are combined with older materials to create a durable combination that can withstand the elements. There are many ways to repair concrete cracks.
Biological methods for crack repair concrete are one of the best options for concrete crack repair. You can use small amounts of fibre to reduce cracking and increase concrete’s tensile strength. Fibres were first used in concrete crack repair in the 1960s. Over the past 40 years, the quality and production of fibre-reinforced concrete as well as the form of the fibres have improved and their application has increased. Natural and artificial fibres have replaced straw and clay, which were used to make cob building materials. Concrete fibres can be made from different materials such as steel, carbon, plasticylene, Kevlar and other metals. Steel fibres offer more benefits than any other type of fibre, including:
1. It is elastic and has high strain rate deformation. This fibre, which was properly formed and has high tensile strengths, is one of the most economical and suitable types of fibre.
2. This is the best concrete additive.
3. Concrete can be improved by using various external construction methods.
4. Mixing it with other concrete materials is easy. Cement Mortar: This method fills cracks up to 1 mm in width with plastic material. It is possible to use Portland cement mortar or mortar with expanding properties if cracks aren’t active.
Sealing with pressure can be done if cracks are present. Epoxy Resin: Fill cracks with epoxy resin injections. This method uses narrow ports of 0.05mm width to place along cracks. The cracks’ surface is then sealed to stop resin leakage and escape. If the crack’s start and end are not at the same height, injection should be done from the lowest to the highest point. Transparent tubes can be used to ensure that the injectable material is injected into cracks in a proper manner. Silica Gel Silica gel can be used to immobilize bacteria.
Silica gel was used for bacterial immobilization as well as crack filler prior to the precipitation CaCO3. It is similar to bacterial cells, yeasts, and algae and creates biological immobilization. To seal cracks, polyurethane can also be used to immobilize bacteria