Wide image of expansion joint followed by the explanation given below.
An expansion joint is a gap in the building structure to allow the movement of the building structure to allow the movement of the building due to temperature changes. An expansion joint is an assembly designed to safely absorb the heat induced expansion and contraction of various construction materials. They are commonly found between sections of slabs, bridges and other structures. With course of time the structure would crack under the stress of thermal expansion and contraction, due to which the expansion joint becomes the main source of leakage in the structure.
Water tightness is the key requirement as impermeability of an expansion joint is determined not only by the joint itself but also by that of its connection to the waterproofing system of the supporting structure at each side. The waterproofing material must not only cope with the movement of the building but also be designed to resist aging that leads to the weakening of the bond on the concrete and causes failure of the system. A highly flexible sealant is required, so that it does not crack with the movement.
The methods used for expansion joint treatment are application of TPE Tapes, polysulphidesealent&highly flexible polyurethane sealer.