Concrete is an extremely versatile and durable building material. Concrete can be used to build long lasting structures even in very harsh environments when it is made with adequate constituents and mix design and properly handled .performance problems that may arise occasionally are often due to the use of materials that do not full fill minimum quality requirements, unsatisfactory specifications or due to inappropriate construction methods. A concrete consists of sand, coarse aggregate (gravel, stone and etc…), cement and water are mixed and hardened to form a stone like material. This reference assignment is a guide to help you to get a good knowledge about concrete.
TYPESOF CONCRETE:
Light weight concrete
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Due to this expansion, some lightweight aggregate shall be
Absorptive. Such aggregate may require pre-wetting prior to concrete batching.
Lightweight concrete has a range in unit weight from about 1280 to 1920 kg/m3 (80 to 120 lb/ft3)
Depend1760 kg/m3 (110 lb/ft3) and have compressive strengths comparable to conventional concreting on the lightweight material used. Some lightweight aggregate will produce concrete o1760 kg/m3 (110 lb/ft3) and have compressive strengths comparable to conventional concrete.
Figure 1 Figure 2
Reinforced concrete
Reinforced concrete (RC) is a composite material in which concrete's ductility and relatively low tensile strength are counteract by the inclusion of reinforcement having higher tensile strength and/or ductility. Advantages of reinforced concrete
1. Reinforced concrete also has greater compressive strength as compared to other materials used for construction good in tension.
2. It has better resistance to fire than steel and capable of resisting fire for a longer time.
3. It has long service life with low maintenance
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The cost of the forms used to cast concrete is relatively high
3. It has low compressive strength as compared to steel (about 1:10 depending on material) which guide to large sections in columns/beams of multistory buildings. Cracks are developed in concrete due to shrinkage and the application of live loads. Concrete cast in situ
Production
Production is a factor for the resulting concrete and consist basically of dosing and mixing the raw materials. concrete properties are affected by flowing parameters during mixing:
• type of mixture – addition of raw materials
• size of mixture _plant quality control
• mixing intensity_ concrete mixer operator
• mixing time_ cleaning/maintenance of mixture Limited and defined time period is considered to place the concrete. The following factors contribute to the success, which is critical for the concrete quality.
• Delivery note check
• Use of the right equipment
• Avoid overhanding the concrete
• Continuous placing and compacting
• Re compaction on large pours
• Take the appropriate holding measures during interruptions
To achieve constant and consistence concrete quality,
Appropriate and correct curing is essential. The curing measures contribute to
At first the Romans did not realize the superior ability of concrete. They began by using it as a fill. They would also cover up the concrete with decorated stones. The concrete they used did not look pleasing because they had mixed it with any arrogate they had available. Later, once they discovered how useful concrete could be, they used it for everything they could. They built their houses, roads government offices, theaters, temples, and everything else they could out of concrete. Concrete was far superior in strength to stone and mortar, and it was easier to make than marble was to quarry and assemble.
If the ancient Roman innovation of concrete, were to not have been significant, it would not have continued to be used across the globe. In fact, ancient Roman hydraulic cement-based concrete was so notable that modern day scientists are trying to, “replicate the exact formula for which ancient Roman concrete was made.” This is due to ancient Roman concrete being so sturdy and strong that aspects of it have lasted over 2000 years without deterioration. Without the innovation of Roman concrete, many of the modern world’s infrastructure would not be stable, causing havoc across the globe. Also, advancements in construction, health, and even safety areas would not be possible, as almost every piece of infrastructure, from sewerage and water pipes, to building and security walls, would not be able to remain as safe to use. This is because the modern world relies so heavily on concrete, with around five billion tonnes of concrete being used around the world each year,becoming the single most widely used material in the construction industry. In fact, around 76% of all first-world infrastructure is reinforced with concrete. Without this substance, much of the modern-world's infrastructure would not be as tall or sturdy as what it currently is, as it would simply deteriorate or break. Hydraulic cement-based concrete is certainly the most significant Roman
Concrete served Rome in many of their constructions and was used it to its fullest possibilities. They mixed the material with lime mortar and called the new building
This essay is to discuss the development of concrete and the arch in Roman history, this essay will also focus on the importance of each in the life of Rome and the results of the use of concrete and the arch.
In this paper we have studied compressive strength of concrete by replacing natural aggregate with recycled aggregate by 25%, 50% and 75%.This mixture formed in the sample of cubes of dimension 150x150x150mm3.
High performance concrete is a concrete mixture, which possess high durability and high strength when compared to conventional concrete. This concrete contains one or more of cementious materials such as fly ash, Silica fume or ground granulated blast furnace slag and usually a super plasticizer
Concrete is one of the world’s most popular construction materials. Some six billion tonnes of concrete is produced each year in the world, making it approximately one ton of concrete for every human being per year (Fardis, 2012, p.116). However, the lifecycle of concrete does not make it the most sustainable building material at the moment. Because of limited natural resources, concerns over green house gases, and landfill problems, concrete production is being cut-back, or at least cannot be increased to keep up with population increase. In this essay, I will look at what makes concrete an unsustainable material and possible solutions to make concrete a more sustainable material.
The Romans basically invented concrete, which came to be known as Roman concrete (opus caementicium). The interesting part that made Roman concrete so durable and long-lasting was that they used volcanic Italian sand, “also known as pozzolana.” (Khan, 2017) The other part that made this such a fine building material was that it could be set underwater, practically unheard of for that time. In addition, when this pozzolana was combined with other pieces such as stones and bricks, it allowed large and very strong structures to be built.
Aggregate: in cement concrete to gain good quality aggregates are used in two groups. Sand and coarse
Improve structural strength, reduces bleeding, less cost, more resistant to chemical and sulfate attacks, and it is environmental friendly.
Concrete in the other hand provided the ability to produce massive structures when judiciously used with bricks. It enable the Romans to utilize stone shapes of different types during their
Concrete is one of the most widely used construction material in the world. The reason for this is because concrete is strong, easy to make and can be molded into various shapes and sizes. Besides that, concrete is cheap, affordable and is readily mix.
Opus caementicium or Roman concrete is a synthetic construction substance that’s composed of an aggregate, a binding agent, and water. In Rome’s case, as discovered by UC Berkley with the extensive analysis of a sample of Roman concrete taken from a breakwater in Italy’s Pozzuoli Bay it was developed by using lime and volcanic rock which formed a mortar, the mortar and volcanic rock were then packed into wooden forms and when seawater was added a chemical reaction occurred, bonding everything together to create concrete (History, 2013). It is uncertain when Roman concrete was developed, but it was clearly in widespread and customary use from about 150 BC; some scholars believe it was developed a century before that.
Concrete is composite consisting cement, aggregates, water and mixtures. It is a material that can be cast into different shapes such as hollow block, pipes or drainage and many more. It is durable and the most attractive construction material in terms of compressive strength. Also, its increasing use is fundamental for sustainable construction.
Pakistan’s cement industry is used to produce concrete, the most desirable construction material. It is used in the construction of roads, railways, bridges, houses, buildings etc.