Repair and structural performance of initially cracked reinforced concrete slabs

Abstract

Crack is one of the most common defects observed in reinforced concrete slabs and beams. Major cracks in concrete structures may occur due to overloading, corrosion of reinforcement or differential settlement of support. To restore the structural capacity of the distressed elements, retrofitting and/or strengthening are needed. There are different techniques available for retrofitting and strengthening of different reinforced concrete structural elements reported in the literature. This paper investigates the structural behaviour of cracked reinforced concrete one-way slab, which is repaired using different techniques. Five different techniques are used for the purpose of repair in the cracked concrete slab namely; cement grout, epoxy injection, ferrocement layer, carbon fibre strip and section enlargement. The slabs were loaded to failure stage and the structural response of each slab specimens have been predicted in terms of deflection, variation of strain in concrete and steel, collapse loads and the failure modes. The efficiency of different repair and strengthening techniques and their effects on the structural behaviour of cracked one-way reinforced concrete slab had been analyzed. It was observed that the type of repair technique used will affect the load carrying capacity of the slab and will lead to a redistribution of the strains and hence stresses in both concrete and steel reinforcement. All repair techniques are found to be able to restore or enhance the structural capacity of cracked concrete slabs.

Characterization of surface crack depth and repair evaluation using Rayleigh waves

“…A typical treatment of surface cracks is application of epoxy agent that seals the openings and protects the interior from environmental influence, offering also improvement of structural strength [1,7,8]. Two of the cracks were totally filled with epoxy.…”

“…The major threat they pose concerns the exposure of the metal reinforcement to environmental agents leading to its oxidation [1][2][3][4][5]. To seal the cracks and protect the interior, and also provide structural strength restoration, injection of epoxy or other agents can be used [6][7][8]. However, both the evaluation of the repair efficiency, as well as the determination of the initial crack depth, are not trivial tasks.…”

Developing a polymer-based crack repairing material using interpenetrate polymer network (IPN) technology

“…Crack repairing is essential for a deteriorated concrete structure not only because it can improve its function and performance, restore its structural integrity, but guarantee its durability by preventing ingress of moisture, oxygen, chloride, and carbon dioxide etc. [4,12,13].…”

Repair evaluation of concrete cracks using surface and through-transmission wave measurements

“…Materials with superior mechanical properties and resistance to corrosion enable different effective repair techniques. Common methods of repair include epoxy or grout injection [7][8][9][10] and surface applications of fiber reinforced polymer strips [10].…”