If you’re having difficulty understanding the differences between cement and concrete, you’re not alone. Many people hear these two words used interchangeably every day at construction sites and in retail stores. The important thing to remember is that people often start to use words from the same industry to describe completely different things as a language evolves because of some sort of strong or even weak connection between the words. Cement and concrete are two of these types of words. In fact, you might have heard someone refer to a concrete sidewalk as a “cement sidewalk.” Yet, these words don’t have the same definitions.
Cement is a type of binding agent that forms a paste when wet. It’s mixed with other ingredients and then molded or sculpted to create long-lasting structures that have the appearance of solid stone. The most common form of cement is made of a fine gray powder usually derived from some combination of lime, silica, alumina, magnesium oxide, iron oxide and other ingredients. Clay and limestone are common sources for these basic components. Other types of cements include Portland Cement blends, bitumen, slag-lime and resin cements.
Construction companies, homeowners and others often mix cement with aggregates – particles and fragments from different materials – and water to create mortars and stucco used in masonry and other types of construction materials like concrete. When mixed with sand and water to create mortar, cement helps bind together bricks and fill gaps. It’s also used as a decorative medium.
You might have heard someone refer to construction cement as “Portland Cement.” Although not all construction cements contain the same ingredients, this description became popular after a British man, Joseph Aspdin, in 1824 started to refer to his new cement mixture to create artificial stone as Portland Cement and patented the cement under the same name. “Portland” refers to the fact that the dried cement and concrete created from his specific mixture had the same external appearance as a particular type of construction stone found in England called “Portland Stone.” Archaeologists have actually traced the origin of man-made cement in the form of non-Portland mixtures back thousands of years to at least the time of the Egyptians.
Concrete is a construction material that comes from mixing cement with sand, crushed stone or gravel and water. It can be shaped as desired, and it’s often poured into molds and forms. As with mortar and stucco, the amount of cement used is critical to the formation of concrete. According to the Portland Cement Association, construction mixtures usually contain 10 to 15 percent cement. Without cement to bind together the rest of the ingredients, concrete couldn’t exist. Cement as a binder also helps strengthen concrete to make it more durable as it ages.
You can find concrete almost everywhere you travel: It’s used to make roads, driveways, garden stones, walkways, foundations, walls, bridges, blocks, counters, tables and many other types of building structures. Although modern concrete is often associated with Portland Cement, concrete can be made of other mixtures and ingredients. As with cement, ancient societies had their own forms of concrete. For example, the Romans had a mixture that they used in the construction of The Pantheon and Aqueducts.
Unlike the ancients, many modern builders use wire mesh, fibers, rods and bars to strengthen and reinforce concrete to make it last longer. Any type of concrete is prone to cracking as it cures. Concrete can also break easily over time when exposed to the elements and natural disasters like earthquakes. Mesh and fibers, for example, help stop existing cracks from spreading and the formation of new cracks.
Both cement and concrete can be modified for decorative purposes with stamps, texturing and engraving tools, color additives and other materials.
The Word Usage Problem
It is okay if you are still asking yourself how the words cement and concrete ever became interchangeable given that they definitely describe completely different things. The exact date and time that this mix-up started is unknown. It likely began somewhere in the construction industry or the retail market:
People can mix both cement and concrete by hand, but a motorized mixer is best for keeping the materials from setting until needed. At some point, someone likely realized that they could mix cement in an electric concrete mixer without using the aggregate and then used that mixer permanently only for cement. Another possibility is that a construction equipment business owner or advertising or sales representative thought that describing a concrete mixer as a “cement mixer” would increase the sales of concrete mixers. Whatever the origin of the usage problem, many companies use both terms to describe motorized electric mixers even though the equipment can mix a wide variety of materials.