Difference Between Non-Hydraulic Cement & Hydraulic Cement

When it comes to the construction of homes, buildings, sidewalks, dams, bridges, etc., cement is an industry staple. Its unique and versatile qualities are well-acknowledged and make for its widespread usage. Despite such high demand for cement, many people are unaware of its basic types. Typically, cement is classified into two varieties based on its hardening and setting mechanism. These are- 

As the name indicates, the non-hydraulic cement does not require water to harden. It will not set when wet conditions exist. Instead, all it needs are dry conditions and the presence of carbon dioxide (CO₂) to set and cure.

Non-hydraulic cement was probably the first known cement to humanity. However, due to its very restricting properties, it was essential to complete the builds quickly before inclement weather conditions hit. 

Hydraulic cement is an inorganic mineral material that reacts with water under ambient conditions forming a hardened and water-resistant product. The cement hardens by hydration in the presence of water. 

Hydraulic cement was first used in the middle ages by the Romans. At that time, “hydraulic cement” was made by combining volcanic ashes and lime. In the 18th century, James Parker patented the Roman cement, but subsequently, it was replaced by Portland cement sometime during the 1850s.

Now that you know what non-hydraulic and hydraulic cement are, let us look at how they differ.

Now we come to the most important question of the day – “Which is better: non-hydraulic cement or hydraulic cement?” To give a fair verdict, it is necessary to recap the qualities of both.

Although non-hydraulic cement is the first invented type of cement, its restrictive nature in requiring fixed dry conditions to cure makes it highly inconvenient to use. It does not harden as long as it is in contact with water. To dry and strengthen, it demands dry conditions. This puts a damper on things as it is not suitable for open construction sites, which are always at the mercy of nature. Due to the harsh fact that it needs controlled conditions, the use of non-hydraulic cement is very restricted.

The limitations of non-hydraulic cement led to the development of hydraulic cement. Due to its fast-drying time under every possible condition, it is now the first choice of all project managers. Hydraulic cement reacts with water and forms stable hydrates of calcium silicate, which results in its quick hardening when poured. Since most constructions are open sites, using hydraulic cement ensures there will be no unnecessary delay in completing the build.

Hydraulic cement cures quickly in dry and wet conditions alike, so it is a better option than non-hydraulic cement, which demands only dry weather. The hydraulic cement was developed for speed and convenience, delivering outstandingly on both. 

While non-hydraulic and hydraulic cement types have their logical and clear applications, it is still easy to garner why hydraulic cement wins hands down. Understanding and acknowledging the limitations of the cement and the expectations for your project, you make the right decision by choosing the cement that best suits your project’s construction requirements. It is only fair to point out that more and more builders place their faith and trust in hydraulic cement, due to which non-hydraulic cement is slowly and steadily becoming obsolete and redundant. Nevertheless, how you want to proceed and which cement you want to work with (whether you want to use one or both) is a choice you must make for yourself. When you do that, simply consider the requirements of the structure you are planning to build, and you shall never go wrong.