Building materials in our world have come a long way. From Wood and rock structures thousand years ago, now we have structures that reach to the sky. Much of this is due to technological advances, especially in the manufacture of cement-based concrete. Cement, one of the essential building materials, which is usually a fine, soft, and powdery substance, made up of a mixture of elements found in natural materials such as limestone, clay, sand, and slate. When cement is mixed with water, it binds sand and gravel to form a hard, firm mass called concrete.

Cement is manufactured by a close combination of mainly four elements; Calcium, silicon, aluminum, and iron. Calcium, the main component, is obtained from limestone and silicon, whereas limestone and silicon receive from sand or clay. Cement is generally grey. However, white cement can also be found, but it is generally more expensive than grey cement. Ordinary Portland Cement (OPC) is the most widely used cement in the world, but another option, Portland Pozzolana cement, has also gained prominence recently. There are different types of cement such as platinum cement, waterproof cement, PPC, OPC, etc. which are available from different brands. Some brands of cement in Nepal are Tansen Cement, Ambuja Cement, Balaji Cement, and many more.  Among all the cement available on the market, OPC and PPC are commonly used.

The difference between OPC and PPC Cement are explained below:

OPC refers to Portland cement (or common Portland cement that spells the "O" in the acronym). It is a widely used type of cement in the world. OPC is the building block for concrete, mortar, stucco, and other standard building bases that require cement in the mix. It is called a type of hydraulic cement, which means that it is a type of cement that not only hardens in response to mixing with water but also becomes waterproof after hardening.  It is made by spraying a Portland cement clinker, which is composed of hydraulic calcium silicates, which turn it into a fine powder. Portland cement clinkers are first made by heating a mixture of raw materials, limestone being the most important. Secondary materials include an aluminosilicate source (often clay, but can also be impure limestone). Other common secondary materials include shale, sand, iron ore, bauxite, fly ash, and slag. They are then heated to about 1450 ° C, which is the standard temperature used to make most cement today. When water is mixed with OPC, it takes a few hours to harden and harden, increasing its shelf life gradually. This process may vary depending on the nature of the mix and the desired result.

Common Portland cement is more common in the region where it is manufactured due to the readily available raw materials. This is also why OPC is today an ideal choice for cement needs around the world, as production costs are very low without compromising quality. As an inexpensive cement product, OPC is widely used in the manufacture of concrete, the world's most popular construction material for roads, houses, buildings, dams, etc. OPC is also used for mortar and grout.

In this regard, PPC refers to a form of Portland cement which is known as Portland Pozzolana cement. PPC is created when pozzolana is used in the mix. Pozzolana is a cement extender that improves the strength and durability of cement and even reduces the cost of making concrete. The term comes from the root word for "pozzolana", a form of volcanic ash. The introduction of pozzolana into a hydraulic cement such as OPC or similar material results in a pozzolana reaction. This, in turn, leads to a cement-like material that uses less cement but has the same or even higher material strength than without this addition. As such, a pozzolan material has little or no cementitious properties itself, but an addition to a cement mix will produce the above results (provided that the cement has a larger volume relative to the pozzolan cement material added). PPC may take longer to set than OPC, but it will produce similar results over time. Although volcanic ash is the earliest form of pozzolana, it now includes natural and man-made aluminous materials or contains silicon, such as clay, slag, silica dust, fly ash, and shale. Note that some of these are, in fact, "waste" from other processes, but are ideal for making PPC. With PPC manufacturing, the use of total OPC in the mix is ​​drastically reduced (by almost 50 percent) to achieve the same results.

Knowing the differences between OPC and PPC is undoubtedly helpful, especially for those in the construction industry. Determining which them works best for the needs and costs of a project can be very important in ensuring the success of a business.