It is the generic term for fine, gray or white powder manufactured using high temperature to produce calcium silicates that, in the presence of water, will undergo hydration producing a product that will bring aggregates together to produce mortar, stucco or concrete.
Joseph Aspdin, an English mason who patented the product in 1824, named it portland cement because it produced a concrete that resembled the color of the natural limestone quarried on the Isle of Portland, a peninsula in the English Channel.
Portland cement is made when materials that contain proper amounts of calcium compounds, silica, alumina and iron oxide are crushed and screened and placed in a rotating cement kiln. Ingredients used in this process are usually materials such as limestone, marl, shale, iron, ore, clay, and fly ash.
All Portland cement is mainly similar but there are eight types of cement that are manufactured to meet various physical and chemical requirements for specific applications:
The two main raw materials used in making Portland cement are calcareous substances like chalk, limestone, marl or shells and argillaceous elements like clay and shale that are rich in silica.
Cement is actually an ingredient of concrete. Concrete is a mixture of aggregates and paste. The aggregates are sand and gravel or crushed stone; the paste is water and Portland cement. Concrete is a hard, strong construction material consisting of sand, conglomerate gravel, pebbles, broken stone, or slag in a mortar or cement matrix. Concrete gets stronger as it gets older. Portland cement is the generic for the type of cement used in virtually all concrete. Cement compromises from 10 to 15 percent of the concrete mix, by volume. In the process called hydration, the cement and water harden and bind the aggregates into a rocklike mass. This hardening process continues for years that it brings the idea that concrete gets stronger and tougher as it gets older.
Curing is a very important step in concrete construction. When concrete has been cured properly, it greatly increases its strength and durability. Through the result of hydration, concrete hardens. It is the chemical reaction between cement and water. Hydration occurs only if water is available and if the concrete’s temperature stays within a suitable range. During the curing period which is from five to seven days after the placement for conventional concrete, the concrete surface needs to be kept moist to allow the hydration process. The new concrete can be wet with soaking hoses, sprinklers or covered with wet burlap, or can be coated with commercially available curing compounds, which seal in moisture.
Gypsum plays a very important role in controlling the rate of which hardening of the cement develops. It must be controlled within the limits to make the cement a useful product in construction. Small amount of gypsum are added to the clinkers at the grounding period.
Much of that depends on what the concrete is used for. In most cases, fiber-mesh is an excellent no-hassle solution to providing additional strength. We also suggest using rebar or wire depending on the use.
The compounds present in Portland cement react with water to form a cementitious crystalline structure that adheres to the sand and aggregate. This helps in binding the mass together and increases its strength till it becomes very hard.
When concrete hydrates, it hardens and gains strength. This hydration process continues over a long period of time. It occurs quickly at the outset and slows down as time passes. It would require a wait of several years before the strength of concrete can really be measured. Since this is impractical, a time period of 28 days was introduced by specification-writing authorities as the time where all concrete should be tested. In this period, a substantial percentage of the hydration has already taken place.
No. There is no universal international standard for Portland cement because every country has their own standard. The United States uses the specification prepared by the American Society for Testing and Material (ASTM C-150) Standard Specification for Portland cement. A few other countries have also adopted this, however, there are countless other conditions. Unfortunately, they do not use the same criteria for measuring properties and defining physical characteristics so they can be virtually "non-translatable". The European Cement Association located in Brussels, Belgium, publishes a book entitled "Cement Standards of the World".
When water is mixed with cement, a smooth paste is produced that remains plastic for a short time. During this period, the paste can be disturbed and remixed without injury. As the reaction between water and cement continues, the plasticity of the cement paste is lost. This early period in the hardening of cement is known as 'Setting of Cement'.
Although often used synonymously with sustainable development, the U.S. government defines green buildings as those that demonstrate the efficient use of energy, water and materials; limit impact on the outdoor environment; and provide a healthier indoor environment. Studies show that green buildings offer improved air quality and more access to daylight in addition to energy and cost savings.
Concrete is a responsible choice for sustainable development. Its durability is a significant sustainable attribute because it will not rust, rot, or burn, requiring less energy and resources over time to repair or replace. Although Portland Cement (PC) is manufacturing is energy intensive, concrete is primarily (86% to 90%) made of sand and gravel, materials which have very low embodied energy and are usually available locally. Structures built with insulated concrete systems have optimal energy performance, due in part to negligible air infiltration and thermal mass. Additionally, concrete is a proven performer for disaster resistance, incurs little waste and can be readily recycled.
First, the length & distance of the area to be poured should be measured. After that, please call our offices to obtain an estimated yardage for the project.
No. Mesh reinforcing does nothing to make the concrete stronger. The mesh reinforcing will keep cracks from opening up once a crack has occurred.
Apparent ready mixed concrete shortages are caused by:
To ensure sufficient supply of ready mixed concrete:
No. Masons ought to be restricted & transit mixer operators ought not to be forced to add water. Consequences of such actions could be severe. Properly designed ready mixed concrete contains optimum water. If the workability (slump) of ready mixed concrete is not as expected, the RMC supplier should be informed. If required, dosing of admixtures along with a small quantity of water would be done by the RMC supplier's technical personnel.
Depending on the workability, RMC would be usable for up to 3 hours.
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