Shear strength in cement and concrete refers to the capacity of the material to resist shear forces that tend to cause one part of a material to slide past another. This property is crucial for structural applications to ensure stability and integrity under loads. The mechanism of shear strength in concrete involves the cohesion within the cement paste and the frictional resistance provided by the aggregates. Adequate shear strength ensures that concrete can handle applied stresses without experiencing shear failure, which is critical in beams, slabs, and columns subjected to lateral loads.