In the most general sense of the word, a concrete is a substance that solidifies to act as glue. Romans were the first to use “modern cement “for purposes of masonry made of crushed stone with vivid lime as binder. They named this substance “caementicium opus “which was later referred to as cement, cimentim , cäment and cement.
Cement is mainly used in construction. It is a gray powdery substance burnt lime and clay, mixed with water and sand to make mortar (a paste used to bind the building blocks together and fill the spaces between them) or with water, sand and gravel to make concrete (one strong durable construction material).
The cement industry is of paramount importance in the development and highly dynamic world today. To initiate, support and sustain growth, it is imperative that the cement industry of a country operates efficiently, effectively and, above all, productive. For a developing country like Pakistan, and amount production of cement used per person indicates the stage of development. Analysts and experts hold the opinion that the demand of cement is directly proportional to the level of economic, population growth and urbanization. Moreover, demand is directly related to the level of construction activities and corresponding occurring across the country.
The history of the cement industry in Pakistan dates back to 1921 when the first plant at Wah was established. When Pakistan became independence, it inherited four cement industries working in operation with an installed capacity of 470,000 tonnes per year. They were located in quotation Karachi, Rohri, Dandot and Wah. The number of units of cement increased to six during the decade of 1948-1958. Pakistani cement industry has changed since then, and has underg...
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...aulic and non-hydraulic. Different type of cement used can produce different amounts of gypsum, clinker and other additives, but only certain types of cement are commonly used today because of its costs and binding power.
Non-hydraulic cement
Hydraulic cement is the cement that can’t harden while in contact with water, compared to the hydraulic cement can. When the non-hydraulic cement is used in the construction, it must be kept dry so that the structure is maintained. Due to the difficulties associated with the wait, which is rarely used in today's market.
Hydraulic cement
Hydraulic cement is cement having a fixing ability and hardens after being combined with water. Hydraulic cement is mainly limestone, certain clay minerals, and gypsum, which are burned at a high temperature together. Hydraulic cement is the cement used in the main construction today.
It is unknown when people first knew about calcium and when people used compounds of calcium. Limestone is a compound of calcium and Limestone was usually used for buildings. The common name for limestone is calcium carbonate. Early Greeks and ancient Egyptians used mortar which was made from heated limestone. It was named for its natural occurrence in limestone with was a common building material, which in itself is an oxide of calcium with the molecular formula being CaCO3. The Latin name for limestone being calx, hence
Besides the known inventions and renovations of the Roman Empire, one of the building materials that the Roman Empire produced was concrete. With its strength, inexpensiveness and its easiness to work, the Roman Empire left an everlasting impact. Concrete that is a mixture of aggregate, which is usually gravel, sand or small stones, binding agents, and water is used to construct buildings and infrastructure. The first one, aggregate, gives the product its mass while the second one, binding agents, is used to harden the product. In the early times of the history, limestone powder was usually used as a binding agent in the mixture. The Romans later used “pulvis puteolanus” (pozzolanic ash), which was a fine volcanic ash as a binding agent and it allowed Romans to have strong concrete that is also durable (Yegeul, n.d.). It was easy to use
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.
The construction industry plays an important role in competitiveness and prosperity of the economy in terms of its significantly contributing to shelter, infrastructure and employment (Anaman and Osei-Amponsah, 2007). A number of researchers have investigated on the vital role of the construction sector to the overall economic growth. In Rhodes’ paper who stated the construction industry in the UK contributed £83.0 billion in economic output in 2012, which accounts for 6% of the total. Also, workforce jobs in the construction industry in UK were 2.03 million in 2012 and 2.12 million in 2013, account 6.4% and 6.5% in total respectively (C. Rhodes, 2013). Oladinrin indicated the significance of construction linkage with the aggregate economy in Nigeria by studying on construction output and Gross Domestic Project (Oladinrin and etc., 2012). A recent report of U.S. Bureau of Economic Analysis showed that the GDP value added of construction industry was $652,723 million in 2014, 3.7% of total GDP (http://www.bea.gov/industry/gdpbyind_data.htm). Besides, a report of U.S. Bureau of Labor Statistics stated the employment by construction industry sector take 4.7%, 3.9% and 4.5% in the year of 2002, 2012 and 2022 respectively (http://www.bls.gov/emp/ep_table_201.htm). The construction industry has been playing an influential role on domestic GDP in China (Zhou and Liu, 2007). A report of National Bureau of Statistics of China
Later on, in the first century AD, the Romans began to use concrete in greater use. The architects of Rome used this concrete to make many structures including domes, arches, and vaults. They added bricks to these structures to improve the strength of the building. After adding the bricks, they put on an extra layer of marble for decoration.
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
The Pantheon was a Roman concrete structure. Roman concrete is a mixture of lime and volcanic ash (pozzolana, found near modern-day town Pozzouli). Roman concrete is also called hydraulic cement-based concrete. It is known for curing relatively rapidly, even in damp condition, thus it could be used for massive construction. The most daring thing about the use of Roman concrete in the Pantheon is that Portland cement needs steel reinforcement due to tendency of cracking caused by tension forces, meanwhile the Pantheon did not. The Pantheon still stands today is because of its special structure.
The Romans discovered many things that would aid the construction of their great civilization. The Romans discovered that a particular mixture of volcanic rock rubble and water could be used to create very strong structures; their concrete mixture could even be used in underwater applications. The Romans used concrete to make foundations for large buildings as well as bridges. They also used concrete as mortar to hold together the stones that made up roads, walls, and bridges. The Romans discovery of concrete allowed them to build very large structures that have survived many centuries.
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.
Construction chemicals are categorized into product portions such as sealers and protective coatings, mortars and grouts, adhesives and caulks, and so on. All such products are widely used in the end user industries such as Non building construction, Nonresidential construction, Residential construction. With the boom in demand, complexity of structures, competitive, environmental conditions and requirement of more potent structure, Construction chemical substances has become an integral aspect of the construction industry. In India, Construction chemical compounds specifically cater to the following
Now a days HPC is expensive than conventional concrete. It require additional materials in some quantities as to meet specified performance.These additional materials are cement,silica fume,...
Concrete is a composite material used widely in the construction industry. Concrete is basically a mixture of cement, water, aggregates and admixture (sometimes). Cement is a fine gray powder that consists of oxidizes calcium, silicon and aluminum. The aggregate used is normally gravel, crushed stone or sand. Admixture is a solid or liquid substance that gives a certain characteristics of the concrete. The cement reacts with water chemically and binds the aggregates together through a process called hydration during hardening or curing of concrete. It means that water helps in the hardening of the concrete while the cement bind the aggregate and also react with water to form a solid mass.
Cement is a finely ground compound of limestone and clay or marl (Chandigarh, 2001). It is used in hydraulic binding since it hardens and binds together aggregates and becomes waterproof thereafter. The most popular use of sand is in building and construction where it is used to bind sand and gravel to obtain concrete used in constructing houses, roads, water channels, among others. Yanbu Cement company produces different types of cement such as Portland cement types I, II, III and IV.
- Environment: Mining activity leads to significant deforestation, noise pollution and emissions. As environmental regulations are gradually becoming more stringent in the cement industry is facing constant challenges to meet these specifications
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.