This article will answer the question “Why is concrete used in construction?” by discussing some of its notable properties in terms of economic and mechanical point of view. Questions about its mode of application in different structures will also be tackled in this blog post.
Why is Concrete Used in Construction?
Concrete is used in construction because of the following properties or characteristics:
- Highly flowable (for shape casting)
- Low maintenance
The term construction or construction project has a wide scope of responsibility. A project, for instance, can be in the form of renovating, maintaining, or constructing buildings or infrastructures. Nevertheless, any of the form requires extensive studies and design requirements for it to be accomplished successfully.
The application of concrete in the construction industry is highly diverse. In fact, the place you are living in at the moment is most likely made of concrete. Several architectural structures including those you dream of taking a picture with are probably made of this versatile construction material. Other structures that can be made with concrete include pavements, fountains, fences, poles, roads, bridges, and so on.
Yes, concrete is economical in comparison to other building materials such as steel and polymers. Its market availability is also exemplary, making it one of the most ubiquitous construction materials in the world. It is also important to note that the insurance cost of concrete structures is generally cheaper on the average compared to those building materials that are prone to fire hazards and those that are highly sensitive to moisture attack.
When comparing concrete and asphalt, concrete pavements are also economical in terms of initial and lifecycle cost. This is because concrete offers less maintenance responsibilities, thereby decreasing the maintenance cost by about a third relative to the cost of asphalt maintenance.
Another desirable characteristic of concretes is their ability to be configured into various shapes and sizes. This property is called flowability, and concrete is highly flowable when in its liquid state. The ratio of concrete components affects the flowability of the mixture, so it is a technique to experiment on some combinations to know the texture and flowability that’s best for you.
It is a common practice to regularly check the flowability or the consistency of the fresh concrete before it is finally poured into the concrete mold. The consistency is highly critical because it dictates the outcome of the concrete structure. When the flowability and consistency are not within the standard levels, the strength and the overall integrity of the structure may be compromised. For example, pouring a pasty concrete into a concrete can result in the formation of cavities which could corrode the reinforcements inside. Corrosion of rebar or any steel reinforcements in the concrete matrix results in a decrease in the structural integrity.
To test the consistency of the fresh concrete mixture before pouring, slump test is performed. It directly measures the workability of the concrete which is a term that describes the ease of performing routine tasks on the building material such as transporting, pouring, casting, and compacting. Slump test could also serve as an indicator that signals when a certain concrete batch is mixed incorrectly; hence, the uniformity within the matrix is assured by this test.
Conducting a slump test is simple as it only requires a slump cone and a freshly mixed concrete mixture. The workability of concrete is assessed by observing its behavior upon the removal of the slump cone. When more falling is observed from the top after cone removal, the more workable the concrete is.
Concrete structures require minimal (if not zero maintenance) over an acceptable period of time compared to other building materials such as steel and wood. Outdoor concrete projects such as buildings do not require coatings on a regular basis to achieve protection against weathering attacks. The cost incurred from frequent surface coating reduces the maintenance cost of concrete significantly.
Does concrete become stronger over time?
Theoretically, yes, concrete could become stronger over time. The reason for this additional strength is the hydration reaction that happens with cement which is a component of your concrete mixture.
Hydration is a chemical reaction that requires seven moles of water to form three moles of calcium hydroxide, three moles of calcium silicate hydrate, and a release of heat. The transfer of heat to the external environment means that the reaction is exothermic, so an increase in temperature should be expected.
The formation of calcium silicate hydrate (CSH) crystals contributes to the durability and strength of the structure. Think of it in a way that the crystals become one with the matrix, filling the available voids in the system. The reduced porosity of concrete increases the density of the structure, so the integrity of the overall unit is improved.
It is important to note that the unutilized water molecules remain in the pore space until the condition becomes favorable to initiate the reaction again. Chances are the moisture from the external environment (e.g. humidity) could penetrate these pores, so the level of moisture inside the microstructure equilibrates again, paying forward an equilibrium reaction.
The timeline of hydration reaction could be treated logarithmically in a way that on the first seven days of setting, the strength development from the formation of CSH crystal has increased dramatically and will then plateau for a period of time before achieving its maximum strength after approximately one month. As mentioned, some pores in the microstructure remain unfilled so that penetration of moisture from the environment is possible, implying that the hydration process (and hence the strengthening of concrete) could proceed over time
Concrete’s versatility is what makes it more interesting as a building material. There are numerous ways to handle concrete, some of which are pumping and spraying.
Concrete can be transferred by pumping using a machine called a concrete pump. The two main categories of this pumping machine are boom concrete pump and trailer-mounted concrete pump.
Boom concrete pump, by its name, uses a robotic boom that can be controlled remotely. The boom is normally attached at the tail end of a truck for a strategic and more accurate transfer of concrete. Furthermore, boom concrete pumps are frequently utilized in large-scale construction projects because of its high-volume capacity that ranges up to approximately 200 cubic meter per hour. In terms of economic point of view, investing in this type of machine is recommended for regular projects as this could reduce labor costs in the long run.
On the other hand, a trailer-mounted concrete pump or line pump requires ducting or flexible hoses to transfer concrete to its destination. Because the hose can be easily detached from the outlet of the supply, the trailer allows effortless setup activities. In comparison to boom concrete pumps, line pumps are more often utilized horizontally at a much smaller capacity. That’s why line pumps are only recommended for use in small-scale projects such as in residential homes.
Other than direct pouring into the mold, concrete is versatile enough to be handled by spraying. Sprayed concrete (also known as shot concrete and shotcrete), are transferred through pneumatic projection along a hose and into the formwork. Because the transfer of material requires high-speed pneumatics, the process of spraying concrete translates into compaction other than the initial purpose of material placement. In other words, spraying concrete is like doing two tasks at a time, thereby reducing labor costs and increasing productivity. One of the direct applications of this mode of concrete placement is through swimming pool projects wherein the construction of the walls of household swimming pools is best done using concrete sprayers.
Concrete’s thermal resistance is one of the factors that attract builders to consider this building material in their construction projects. Resistance to heat is directly related to resistance to fire which translates to the duration by which a structure remains stable in terms of mechanical properties when exposed to elevated temperatures.
Yes, concrete has impressive thermal resistance, owing to its chemical components such as cement and rock aggregates. This stable mixture is non-reactive and has higher heat capacity compared to its other building material counterparts.
This article completely answered the question “Why is concrete used in construction?”. It was explained that concrete is preferred in the construction sector because it has more promising economics and mechanical properties than other building materials. The characteristics of concrete discussed in this blog post were being economical, flowable, easy to maintain, versatile, and thermally resistant.
For any questions and suggestions about this article, please feel free to submit your thoughts in the comment section below.
Frequently Asked Questions (FAQs): Why is Concrete Used in Construction?
Which cement is used in construction?
The most commonly utilized type of cement in the construction industry is the Ordinary Portland Cement of POC. This cement type is both composed of alumina silicates such as clay and shale, and calcium carbonates such as limestone, marl, and chalk.
What are the 3 components of concrete?
The three components of concrete are cement (commonly Portland cement), water, and rock aggregates (commonly a mixture of rock, sand, and gravel). The binding agent of mixture is cement which becomes active upon mixture with the other concrete components.
What is the disadvantage of concrete?
Concrete alone has a weak tensile strength which implies that it could not withstand large amounts of tensile loading. This is also the reason why concrete is reinforced by steel. The high tensile resistance of steel improves the overall mechanical property of the structure, leading to a more durable concrete.
What are the types of cement?
The different types of cement are the following:
- Ordinary Portland Cement (OPC)
- Portland Pozzolana Cement (PPC)
- Rapid Hardening Cement
- Extra Rapid Hardening Cement
- Low Heat Cement
- Sulfates Resisting Cement
- Quick Setting Cement
- Blast Furnace Slag Cement
What are components of cement?
The components of cement are minerals of calcium, silicon, aluminum, iron, and other compounds. Cement is produced by letting raw materials such as limestone, shells, chalk, marl, shale, clay, slate, silica sand, and iron ore be exposed to high temperature kiln. The manufacturing process enables combustion reactions that produce large amounts of greenhouse gases, that’s why the cement industry is seen as bad for the environment.
How important is concrete?
Concrete is important in the construction industry which is a highly relevant sector in the growing demand for infrastructures. This is a common building material in various construction purposes such as the construction of buildings, slab, stairs, and houses.
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