Repair materials can improve substrates properties besides those for which they were designed, i.e., a material for waterproof and surface protection can contribute to the residual strength of beams, due to its penetration via cracks, becoming an integral part of the concrete, sealing empty capillaries and shrinkage cracks. In the present work, compressive tests and inverted Four-point Bending tests were carried out in concrete cylindrical and beams samples with and without permeability-reducing concrete admixture embedded in the mixture, cured in wet chamber for 28 days. After load application until the beams cracking moment up to 0.4mm, a crystalline waterproofing coating material was superficially applied on those cracks. The treated beams were stored in water immersion curing for more 28 days. The analysis of 56-day residual resistance improvement was held, subjecting the prismatic specimens to new bending test. Compressive strength was not influenced by admixture A pre-addition in concretes. In the other hand, small increase on stiffening at the initial reopening of main crack of beams at flexural tensile strength was observed.