Concrete Basics

What is Concrete?

Concrete is a vital material that is not directly derived from nature like other components including iron, nickel or aluminum. Even though people often interchange the words concrete and cement as though they mean the same thing, they are not the same thing, but are very much interdependent.  Cement is a powdery material made of calcined lime and clay and is used in the production of concrete. When cement is mixed with water and aggregate (sand, gravel or rock), the blended mixture hardens by a chemical reaction that generates heat, turning the mixture into solid concrete.

While still a wet mixture, concrete can be poured to form structures, sidewalks, floor slabs, or nearly any other type of shape or design. The hardened material is durable enough to be used in a variety of applications including the construction of dams, bridges, roads surfaces and buildings.

The History of Concrete

The use of concrete began millenniums ago and was used heavily throughout Europe and Asia in the time of the Roman Empire. The technology was lost for well over 1000 years, during the dark ages, and did not resurface until the mid-eighteenth century. Since then, it has been used extensively and continues to be recognized as one of the most necessary building materials used worldwide.

Strength and Durability

Concrete has natural hydraulic properties, and can harden to full strength underwater. This makes it the ideal material for constructing piers, docks, bridges and other structures that require underwater construction. The versatility of its fluid properties before hardening lends itself as the ideal material for manufacturing archways, fountains, and other structures that remain wet.

The Curing Process

The curing process for concrete increases its durability and strength. As a natural result of the hydration process, concrete hardens quickly so that it can be “finished” to a smooth surface, and the forms used in the pouring process can be pulled away. However, complete curing can take weeks or longer for the full hydration process to complete. During many applications, conventional concrete is often kept moist for five to seven days to maximize the benefits of the hydration process, through a variety of means.

The Effects of Temperature

Pouring concrete during times of extreme temperature can make it challenging for the mixture to properly cure. During days of extreme hot temperature, the newly placed concrete might be compromised when water evaporation happens to quickly during the pour and finishing process. Likewise, on extremely cold days, close to freezing, the process of hydration often comes to a standstill.

The effects of extreme cold temperatures can cause a negative impact on the durability and strength of the poured concrete. The ideal temperature of newly placed concrete should be 50 degrees Fahrenheit (10 degrees Celsius) throughout the curing.

The Concrete Surface

Typically, the concrete surface remains unaffected by most materials. However, when in contact with acid, the concrete surface can begin to deteriorate. However, there are ways to provide maximum resistance to chemicals and acids through protective treatments.