This document provides information about concrete beams and concrete structures. It discusses the differences between cement and concrete, how concrete gets stronger over time through hydration, and the importance of curing. It explains that concrete is strong in compression but weak in tension, so it is reinforced with steel rebar or mesh. Composite materials made of concrete and fibreglass mesh are also discussed. The document covers testing of concrete properties and principles of pressure, buoyancy, chemical and nuclear changes in matter.