What is concrete? Concrete is a mixture of cement, sand and water and normally gravel or crushed stone. Concrete can have additives or specialty compounds, chemicals or other mixtures to give concrete special properties. Water must be measured correctly and even high moisture in the sand can influence the properties of cement. In fact, even air can effluence the properties of cement.
Normally, concrete is used to make structures. By itself concrete has great compressive properties. Concrete when used with steel, such as reinforced or steel reinforcement bars, has great potential to create useful structures. Concrete is not the only material used to make structure either!
Little Smokey's Bookshop has popular books on concrete and structures.