Whether you have been engaged in construction, be it a house, bridge, or a commercial building you have probably came across the name Portland Pozzolana Cement, or each time they simply call it PPC. But have you ever questioned yourself what makes this cement a reliable one? This solution can be found in one of the main Indian standards: the one that is called IS 1489 (Part 1), issued by the Bureau of Indian Standards (BIS).
We should first simplify this definition before you get to know what this standard entails, why it is important, and how it relates to the quality of construction in India.
What Does Portland Pozzolana Cement Mean?
Portland Pozzolana Cement Portland Portland Pozzolana Cement is a blended cement that is produced by mixing Ordinary Portland Cement (OPC) clinker with pozzolanic materials and gypsum. The Pozzolanic materials are substances, which, when on their own, do not have much of an adhesive quality, but when combined with water and calcium hydroxide react chemically to create compounds that give cement its strength.
Pozzolanic materials incorporated in PPC are of two kinds:
What Is Fly Ash?
Fly ash is a fine material which is a by-product of coal burning in thermal power plant. The fly ash was treated as a waste industrial waste over the years, and it posed an environmental problem when dumped in substantial amounts. Nevertheless, engineers and scientists have found out that fly ash possesses great pozzolanic properties hence makes it a useful substance in making cement.
The fly ash cement is a win-win situation: it decreases the industrial waste, minimizes carbon emissions of the cement manufacturing, and enhances the specific properties of the end product.
What Is IS 1489 (Part 1)?
The Indian Standard specification of Portland Pozzolana Cement – Fly Ash Based is the Indian Standard specification, 2017, which is IS 1489 (Part 1). This standard provides the regulations and the standards that manufacturers should be guided by when making fly ash based PPC in India.
To put it simply, the official quality rulebook of this type of cement is IS 1489 (Part 1). Any bag of PPC cement bought in India should meet such standard to be bearing the BIS ISI mark.
Important Requirements According to IS 1489 (Part 1)
This is what the standard provides:
Fly Ash Content
Fly ash can be included in the usual percentage of 15-35 mass of Portland Pozzolana Cement. It is a well-calculated range: inadequate amount of fly ash will not provide the desired benefits and excessive amounts may decrease strength.
Fineness
The cement has to have a specific surface area (more commonly referred to as the fineness of Blaine) of 300 m2/kg. The finer the cement the more reactive and the stronger bonding.
Setting Time
Initial setting Time: At least 30 minutes – This is to allow ample time to the workers to set and complete the concrete before it is allowed to dry.
Final Setting Time: A maximum of 600 minutes (10 hours) – the cement should harden at a reasonable period.
Compressive Strength
In IS 1489 (Part 1) minimum compressive strength values at various ages are given:
At 3 days: minimum 16 MPa
At 7 days: minimum 22 MPa
At 28 days: minimum 33 MPa
The values are what make the fly ash-based PPC structures to have the necessary load-bearing capacity in the long run.
Soundness
Cement should not swell too much upon its consolidation. Crumbling cement may lead to cracks in constructions. The criterion restricts growth by the Le Chatelier technique to 10 mm.
Chemical Requirements
The standard also regulates chemical composition of PPC, such as magnesium oxide (MgO), sulphur trioxide (SO3) and the loss on ignition to make sure that the cement is safe and resilient.
Why Is IS 1489 (Part 1) Important?
This standard of BIS is significant due to some reasons:
Quality Assurance: It ensures that all bags of fly ash based PPC are of a minimum quality thus safeguarding builders and final users.
Structural Safety: PPC structures have a higher level of resistance, durability, and strength against chemical attacks such as sulfate and chloride attacks.
Environmental Benefits: As fly ash (industrial by-product) substitutes a fraction of OPC clinker, the creation of PPC results in a smaller CO2 emission than OPC and thus it is a greener substitute.
Cost Effectiveness: PPC tends to be less expensive than OPC and IS 1489 will make sure that you do not sacrifice the quality to achieve that cheaper price.
Long-term Durability: Fly ash-bearing PPC is characterized by the low heat of hydration which minimizes the chances of thermal cracking of huge pours of concrete such as dams and foundations.
Where Is PPC based on Fly Ash used?
Due to its exclusive characteristics, PPC that complies with IS 1489 (Part 1) finds extensive application in:
Interim structures such as dams and retaining walls made of masses of concrete.
Houses and office buildings.
Structures in the sea which come in contact with salt.
Underground structures where the sulphate resistance is required.
Plastering and masonry work
Final Thoughts
Bureau of Indian Standards (IS 1489, Part 1) is important in the quality, safety, and reliability of Portland Pozzolana Cement – Fly Ash Based in India. As a homeowner, a contractor or a civil engineer, being aware of this standard, can guide you to make the right choice when choosing the correct cement to use in your project.
Next time, when you will buy a bag of PPC cement you will see BIS ISI mark which ensures the standard quality of the product, and it is safe to use in your construction.
Construction of India, brick by brick.
