Final answer:
Steel is the material that when embedded in concrete, strengthens it by providing tensile strength, making concrete and steel a common composite material in construction.
Step-by-step explanation:
When embedded in concrete, the material that strengthens it is steel. The combination of concrete and steel provides a composite material where the concrete resists compression and the steel provides tensile strength. This synergy creates a strong and durable material used in a variety of construction applications. It is important to note that while materials like wood, plastic, and glass have their own unique properties and uses in construction, steel is typically chosen for reinforcement due to its compatibility with concrete's thermal expansion and its ability to improve the tensile strength without compromising the integrity of the structure.
Concrete itself is a mixture of coarse aggregate with fine aggregates like shale, clay, or slate. It's popular in construction for its load reduction capability, durability, and excellent thermal protection properties as compared to other materials like brick.
The reinforcing rods, often called rebar, are made of steel specifically because steel's coefficient of linear expansion is nearly equal to that of concrete. This allows the reinforced concrete to maintain its integrity through temperature changes without experiencing detrimental thermal stress.