I have often wondered why white cement is not more popular. I have learned that the most common reasons are: it is more expensive, there is no specification for white concrete and users don’t know about it.
In an effort to raise awareness of this important product, I have been writing a blog entitled Why Cement? Why White Cement? which can be found at www.whycementwhitewhitecement.com. In this blog I write about the many reasons that white cement is so desirable, including its beauty, its infinite color possibilities and its sustainability attributes.
Please visit my blog, read all about the benefits of white cement and check out projects around the world featuring this amazing product. Share your thoughts with me, leave a comment or challenge my ideas!
Why Cement? Why White Cement?
Cement is a binder, a substance used for construction that sets and hardens independently, and can bind other materials together. The most important use of cement is the production of mortar and concrete—the bonding of natural or artificial aggregates to form a strong building material that is durable in the face of normal environmental effects.
Portland white cement – a type II/V low alkali cement with optimized magnesium oxide content – is designed to impart a white color when mixed with white sand in the production of architectural concrete or masonry mortars. White portland cement has very low iron and manganese contents, which allows it to keep its bright appearance during exposure to weather or other atmospheric conditions.
In addition to its aesthetic advantages, white portland cement also offers strength, improved workability and durability. It can be used in combination with white aggregates to produce white concrete for prestige construction projects such as airports, hotels and hogh-rise offices.
White portland cement should not be confused with white blended hydraulic cements (GBFS or GGBS) or with ternary blended cements (PPC).
Why white cement?: The whiteness of white cement is dictated by its raw materials and the manufacturing process. Metal oxides (Fe2O3, Mn2O3, Cr2O3) influence the whiteness and undertone of the material. White cement allows for color selection without chemical pigments.
Why is it important? White cement industry serves a niche market that is estimated at 2 million tons/year. In comparison to gray cement, a ton of white cement represents a higher value and higher prices. Hence, white cement production consumes more energy per ton than gray cement production, but it can be offset by the higher selling price.
The importance of white cement could never be over-emphasised. White cement is a very versatile product and can be used in a number of ways. It has been used as the binding agent in mortars and concretes for centuries, but its use has been relatively limited because of its high price compared with grey cement. This is now changing due to the increasing demand for white concrete and mortar products which, in turn, has led to many cost implications that have resulted in lower prices.
White cement has high aesthetic qualities, which means it can be made into products that are guaranteed to stay whiter and brighter than grey cement products. The colour also remains stable over time as it is not affected by UV light or sulphates in water. White cement is also more resistant to chemical attack, so acid rain won’t damage it as much as it would grey cement. White cement offers a range of different finishes including smooth, textured or matt surface finishes which can give any structure that extra edge needed to make it stand out from the crowd.
If you have seen white concrete, you may have wondered what makes it white. Is it a special kind of cement? Is it some kind of paint? Why is white cement more expensive than gray cement? Is white portland cement the same thing as white masonry cement? These are all questions we hear in our office from time to time and thought we would address them in our blog.
First off, white cement is not a special type of portland cement. White portland cement is made from raw materials containing little or no iron or manganese, the substances that give conventional cement its gray color. The primary difference between white and gray portland cements is in the raw materials used and the manufacturing process. The chemicals used to produce the color depend on the manufacturer.
There are several forms of white portland cement available for different applications:
Type I (white): Normal general purpose finish applications such as precast concrete, architectural concrete, ornamental concrete and masonry units.
Type III (white): High early strength for projects requiring rapid hardening such as paving, dams and cold weather concreting.
White Masonry Cement: Meets ASTM C91 specifications for use in manufacture of clay masonry units. Used to make Type S
White cement, or white portland cement (WPC), is a type of specialty cement, containing little or no iron or manganese (contaminants that often give conventional gray cement its gray color). White cement allows for a wide range of color options in the overall look and design of the concrete project.
WPC is produced in white or very light gray. It is commonly used for architectural purposes where traditional grey concrete could leave unwanted stains or streaks. WPC also has a lower heat of hydration than grey cement which reduces the risk of cracking from thermal stresses when placed in thin sections. Furthermore, WPC tends to wear better at joints and edges than traditional cement. Some manufacturers claim that it also produces a more consistently colored product, although this claim is not widely accepted within the industry.
Ever wonder why cement can be white or gray?
Cement is a manufactured product made by blending different raw materials and heating them at a high temperature. Basically, cement is the glue that holds concrete together, making it an essential ingredient in today’s construction materials. Concrete is made up of three basic components: water, aggregate (rock, sand or gravel) and Portland cement. Cementing materials are any materials that will set and harden independently and resist chemical attack while maintaining structural integrity up to engineering requirements. Portland cement is not a brand name, but the generic term for the type of cement used in virtually all concrete, just as stainless is a type of steel and sterling a type of silver. Cement comprises from 10 to 15 percent of the concrete mix, by volume. Through a process called hydration, the cement and water harden and bind the aggregates into a rocklike mass. This hardening process continues for years, which is why concrete gets stronger as it gets older.