Concrete is thinner, stronger and more durable than mortar; whereas mortar is used as a bonding agent between building materials, concrete is used for structural projects, such as beams or walls. The differing compositions of these materials makes them ideal for different purposes. Concrete and mortar are not used interchangeably without compromising the structural integrity of a building.
Both concrete and mortar are mixtures of water, cement and sand. However, concrete has the additional element of gravel and other coarse aggregates. This gives concrete a greater level of durability than mortar. Concrete needs a low water-to-cement ratio and is thinner than mortar when mixed. Builders often reinforce concrete with steel and use it for the structural aspect of building. Concrete can also be used decoratively for fireplaces, porches, pool decks and countertops.
Mortar lacks the gravel component of concrete; its composition is a mixture of water, sand and cement. When hydrated, mortar becomes thick, making it a great adhesive for building materials. It has a higher water-to-cement ration than concrete. Mortar commonly holds together things such as bricks and tiles. Because mortar is not as durable as concrete, and because it must be replaced every 25 to 50 years, it is not practical for structural projects.