In the previous post, we talked about Concrete Technology and its importance in the construction industry. This post covers the concrete constituents in simple language and the coverage is comprehensive about their properties.
Concrete Constituents and their functions
If you are reading this post, you must already know about the basic concrete constituents mentioned below:
- Cement
- Aggregate (Coarse and Fine)
- Water and
- Admixture
However, today's modern-day concrete is designed with additional mineral and chemical additives. We will learn about all the concrete constituents and their properties. Primarily we'll cover the basics of the components.
Cement
Among the basic concrete constituents, cement is an expensive material. It is the major component that affects the overall economy of an infrastructure.
Cement is available in varieties like Ordinary Portland Cement (OPC), Portland Pozzolana Cement (PPC), Portland Slag Cement (PSC), Quick Setting Cement, Rapid Hardening Cement, White Cement, etc. with different properties which are necessary for the durability of the structure depending upon the location and nature of work like Reinforcement Cement Concrete (RCC), Plain Cement Concrete (PCC), Prestressed Concrete (PSC), etc.
Cement is a binding material manufactured by grinding calcined limestone and clay to a fine powder when mixed with water producing a solid mass. Generally, it is a greenish powder composed of lime, silica, alumina, iron oxide, magnesium, sulfur oxide, soda, and potash after a thermochemical reaction to produce clinker. It is then grounded to fine powder adding gypsum and other additives to a proportion to produce cement.
Aggregate
To know more about concrete, an engineer or official involved in the concrete industry must know about the properties and functions of aggregate as it is the major concrete constituent.
If we talk about the volume of concrete, aggregate makes up between 70 to 80% of the total volume of normal concrete as they give body to the concrete. For the concrete, to give satisfactory performance, aggregate must be strong, durable, and inert and the sizes of the constituent particles must be appropriate for the desired application as their impact on various properties of concrete is undeniably considerable.
Aggregates are normally separated into size fractions and are described as coarse aggregate and fine aggregate. In concrete, where a wider range of size particles is necessary, constituents may be selected and mixed together to get appropriate overall grading of aggregates.
Water
Water is a necessary component among concrete constituents. I mean, even if you mix up all the concrete constituents without water you won't make a block of concrete, would you?
Without water, there will be no chemical reaction between cement and water to form cement gels which help to form the strength of concrete. Generally, the quantity and quality of cement and aggregate are given importance but the control of the quality of water is neglected. The quantity and quality of water in concrete decide the desired properties of fresh concrete and have a great influence on the strength and durability of concrete.
Since the quality of water influence the strength and durability of concrete, we must know about the purity and quality of water. If water is fit for drinking then it is fit for making concrete but water for making concrete may not be fit for drinking. Practically talking, the source of water should be reliable.
Admixtures
Generally, we can define admixture as an extra, either mineral or chemical material added with basic concrete constituents, for modifying the properties of concrete. It can be added to other concrete constituents during or before batching and mixing process to make concrete suitable for different conditions.
Admixtures, optional concrete constituents, are added to modify the workability, pumpable properties, initial setting time, strength development, appearance, permeability, and durability from fresh to hardened concrete. In modern-day concrete, chemical and mineral admixtures have become necessary concrete constituents to produce a specific performance of concrete.
Though a large number of blogs and websites are available on the internet, I have tried to keep it as simple as possible to make this blog understandable for everyone either be an engineer or a contractor.
Although a small effort has been made to present this blog simple and down-to-earth, yet if there are any suggestions kindly write in the comment section.