Contrary to a statically applied load, blast load corresponds to a larger force intensity with a lesser time span which when comes in contact with the structural elements results in higher internal stresses. The portable natural gas or LNG cylinder used in the household may pose serious threat to the integrity of the structure due to its associated leakage and/or cylinder gas blast, as a result, strengthening of structural element is required for smooth and safe operation. Textile reinforced mortar (TRM) has been widely used as a substitute to the fiber reinforced polymer (FRP) for the strengthening of the reinforced concrete structural elements. This study numerically investigates the behaviour of the post blast reinforced concrete slabs strengthened with TRM. The load-bearing capability of the damaged slabs reinforced with three layers of TRM was comparable to that of the undamaged slab. The strengthened slabs exhibited improved stiffness in the initial elastic phase and followed the control slab pattern till failure.