Portland cement is the most commonly used cement for construction purposes.
- 1 Why cement is used in construction?
- 2 Why Portland cement is used in construction?
Why cement is used in construction?
Cement powder, here conditioned in bag, ready to be mixed with aggregates and water. Dispersing dry cement dust in the air should be avoided to prevent health issues. Cement block construction examples from the Multiplex Manufacturing Company of Toledo, Ohio, in 1905 A cement is a binder, a chemical substance used for construction that sets, hardens, and adheres to other materials to bind them together. Cement is seldom used on its own, but rather to bind sand and gravel ( aggregate ) together.
- Cement mixed with fine aggregate produces mortar for masonry, or with sand and gravel, produces concrete,
- Concrete is the most widely used material in existence and is behind only water as the planet’s most-consumed resource.
- Cements used in construction are usually inorganic, often lime or calcium silicate based, which can be characterized as hydraulic or the less common non-hydraulic, depending on the ability of the cement to set in the presence of water (see hydraulic and non-hydraulic lime plaster ).
Hydraulic cements (e.g., Portland cement ) set and become adhesive through a chemical reaction between the dry ingredients and water. The chemical reaction results in mineral hydrates that are not very water-soluble and so are quite durable in water and safe from chemical attack.
This allows setting in wet conditions or under water and further protects the hardened material from chemical attack. The chemical process for hydraulic cement was found by ancient Romans who used volcanic ash ( pozzolana ) with added lime (calcium oxide). Non-hydraulic cement (less common) does not set in wet conditions or under water.
Rather, it sets as it dries and reacts with carbon dioxide in the air. It is resistant to attack by chemicals after setting. The word “cement” can be traced back to the Ancient Roman term opus caementicium, used to describe masonry resembling modern concrete that was made from crushed rock with burnt lime as binder.
The volcanic ash and pulverized brick supplements that were added to the burnt lime, to obtain a hydraulic binder, were later referred to as cementum, cimentum, cäment, and cement, In modern times, organic polymers are sometimes used as cements in concrete. World production is about four billion tonnes per year, of which about half is made in China.
If the cement industry were a country, it would be the third largest carbon dioxide emitter in the world with up to 2.8 billion tonnes, surpassed only by China and the United States. The initial calcination reaction in the production of cement is responsible for about 4% of global CO 2 emissions.
Where is cement used in construction?
Where is cement used? – Cembureau Airports | Green roofs | Bridges | Water pipes | Grain silos | Tunnel | Multi storey car parks | Elevated trains | Swimming pools | High rise office buildings | Water reservoirs | Dikes | Wind Power | Roads | Dams | Cargo ships | Statues | Stairs |High rise residential buildings | Houses Cement plays a key, but often unnoticed, role in our lives.
Cement is mainly used as a binder in concrete, which is a basic material for all types of construction, including housing, roads, schools, hospitals, dams and ports, as well as for decorative applications (for patios, floors, staircases, driveways, pool decks) and items like tables, sculptures or bookcases.
Concrete is a versatile and reliable construction material with a wide range of applications. When looking at possible pathways to reduce the carbon footprint of the European cement industry, it is important to examine some of the characteristics of the industry that will influence the availability or viability of emission reduction options. The cement industry is CO 2 -, energy- and material-intensive. Measures to decrease energy consumption and to improve resource efficiency will de facto, reduce CO 2 emissions (hence the focus on CO 2 emissions). The combination of process emissions (emissions released when limestone is transformed into lime during the production process) and emissions from the required thermal energy leads to substantial CO2emissions for each tonne of cement. The cost of constructing a new cement plant with 1 million tonnes of annual capacity is typically more than €150 million. Modernisation of existing cement plants is also very expensive. In addition, and in order to meet European environmental legislation, operations face major investments and operating costs.30% of the cement industry’s total operating expenses relate to energy costs.
- The cost of a new cement plant is equivalent to around three years of turnover, which ranks the cement industry among the most capital-intensive industries.
- Long periods are therefore needed before these large investments can be recovered.
- Plant modifications have to be carefully planned, as typical investment cycles in the sector last about 30 years.
Consequently, achieving the 2050 low-carbon economy roadmap for the European cement industry will be based on balancing recent investments with planning new investments in the coming decades. Although produced from naturally occurring raw materials that can vary widely from plant to plant, cement is a product manufactured in Europe according to a harmonised standard. Despite the existence of specialised segments, many cements are interchangeable, which promotes a competitive cement market. This also means that European production can be very vulnerable to cheaper imports. Cement is mostly locally produced and locally consumed. However, it is also transported over long distances by sea, river and land as plants rationalise and exploit efficiencies of scale. Land transportation costs are significant. Transporting cement costs about €10 per tonne for every 100km by road and around €15 per tonne to cross the Mediterranean Sea 2, Cement consumption is closely linked to economic development in the local region or country. In mature markets, such as Europe, where cement consumption per capita still varies considerably from one country to another, cement sales are dependent on activity in the construction sector, which closely follows (usually after a brief delay) general economic activity.
Why Portland cement is used in construction?
2.1.6 Application – Portland cement is used for general construction purposes where special properties are not required. It is normally used for the reinforced concrete buildings, bridges, pavements, and where soil conditions are normal. It is also used for most concrete masonry units and for all uses where the concrete is not subject to special sulfate hazard or where the heat generated by the hydration of cement is not objectionable.
What is Type 1 and 2 cement used for?
Why Concrete is the Most Used Construction Material?
Portland Type I/II cement is typically considered a general-purpose cement and is most often used for general construction purposes, such as precast concrete products, reinforced buildings, floors, sewers, bridges, and pavements.
Can we use PPC cement for construction?
Portland pozzolana cement (PPC) is used for the construction of houses, schools, and residential building slabs. PPC is cheaper than ordinary Portland cement. Thus to reduce the building making cost, PPC should be adopted. Both the PPC and OPC cement is used in the construction of slabs.
Why use OPC 43 cement?
43 Grade Ordinary Portland Cement (OPC 43) – OPC 43 cement shall conform to IS:8112-1989 and the designed strength of 28 days shall be minimum 43 MPa or 430 kg/sqcm. Even though 43 Grade cements’ early strength is less as compared to that of 53 Grade, with time it will attain the same ultimate strength as that of 53 Grade cement.
In the case of 43 Grade cement, the initial setting of cement is slower as compared to 53 Grade cement. In other words, the hydration process and consequently, the release of heat is moderate and therefore, occurrence of micro cracking is much less and can be easily controlled by proper curing of the concrete / masonry work.
Unless a project requires very high strength cement, the use of 43 Grade OPC is generally recommended in general civil construction work such as residential, commercial and industrial structures. It is used in RCC works, preferably where the grade of concrete is up to M-30.
It is also extensively used in the manufacture of pre-cast items such as blocks, pipes, tiles etc., and also in asbestos products such as sheets and pipes. Since OPC 33 has mostly been phased out in the country, OPC 43 is nowadays largely used in plastering, flooring and other non structural applications where OPC 33 was earlier being used.
The physical and chemical characteristics of OPC 43 Grade Deccan Cement very comfortably meets BIS requirements. Particularly, the compressive strength of Deccan Cement OPC 43 is significantly higher than the standards specified by BIS.
Which is better OPC 43 or 53?
OPC 53 sets quicker than OPC 43 and has a quite low initial setting time. It is used in structures where rapid strength gain is required like large load bearing structures like bridges, huge buildings, etc. OPC 43 on the other hand doesn’t set so quickly and has a normal initial and final setting time.