Green Buildings And Rapid Hardening Cement: A blog about cement that hardens much faster than traditional concrete.
Rapid Hardening Portland Cement (RHPC) is a hydraulic cement that sets and hardens more rapidly than other types, and produces a higher early strength. This makes it ideal for applications such as rapid repair of concrete pavement, where the concrete must be returned to service quickly. RHPC is manufactured by inter-grinding a higher percentage of clinker, gypsum and other pozzolanic materials with the standard ingredients of Portland cement clinker, or by blending RHPC with ordinary Portland cement.
The building industry is one of the biggest consumers of water. The cement industry is also one of the biggest producers of CO2, which is known to be a greenhouse gas. But there are new cements that are being used in some parts of the world, which could reduce both water consumption as well as CO2 emissions.
It’s called rapid hardening cement and it is made by grinding up limestone and clay into very small particles. This way it can harden faster than regular concrete. It has been tested in some parts of the world with great success.
According to a study by the University of Texas and the University of Michigan, rapid hardening cement could reduce water consumption in the building industry by 30% if it is used instead of traditional concrete.
On a related note, there have been some interesting discoveries about green buildings and carbon dioxide emissions lately. Carbon dioxide emissions from buildings account for about 25% of total global CO2 emissions, according to an article published in Science Magazine on February 10th, 2017 . Researchers from Lawrence Berkeley National Laboratory have developed a new way to measure the amount of carbon dioxide emitted from buildings around the world.
By using satellite images, researchers have found that large cities like New York emit less carbon dioxide than smaller cities like Chicago or
The rapid hardening cement is not a new invention, in fact it was invented over 100 years ago. The problem was that at the beginning of this century, not only were the production processes very expensive but also the manufacturing process required an additional input of energy which could make the cost even higher.
In the last few decades many researchers have been working to improve this technology and make it more affordable. But finally we have reached a point where both its production costs and its environmental impact are much lower than those of traditional concrete.
What makes this cement different?
The most important difference is in the composition of this cement. It is made with pozzolanic materials such as fly ash and metakaolin, which are by-products of coal combustion plants and kaolin mines respectively. These materials have a very fine grain size which allows them to react very quickly with calcium hydroxide (the main binder used in concrete) forming calcium silicate hydrate (C-S-H) that hardens much faster than traditional concrete (in a matter of hours instead of weeks). This type of cement has also other benefits such as better resistance to sulfate attack or chloride penetration as well as better resistance to alkali-silica reaction when compared with traditional Portland cement.
There are many people who have heard about rapid hardening cement but don’t know what it is or why and when it can be used. We will be happy to answer your questions and shed some light on this topic.
Rapid hardening cement is produced by increasing the amount of gypsum in traditional Portland cement. This kind of cement is used in those situations where time is critical, such as bridges, roads, airports, pre-cast concrete operations and other construction works where fast form removal, rapid strength gain and high durability are important. It thus differs from standard Portland cements with low heat of hydration which allow slower strength development at lower temperatures (below 20 degrees Celsius).
The use of rapid hardening cement in construction projects was first patented by the famous French engineer Francois Coignet in 1867. Since then the use of this type of cement has increased significantly especially in developing countries where rapid construction is needed.
Nowadays rapid hardening Portland cement is widely used in roadworks, bridges, tunnels and all types of infrastructural projects due to its fast setting properties, high strength development and high durability.
Rapid Hardening Cement (RHC) is a special cement which gains strength rapidly when compared to ordinary Portland cement. RHC is produced by either intergrinding the OPC clinker with very finely ground granulated blast furnace slag or blending the ground granulated blast furnace slag (GGBS) with very finely ground Portland cement clinker.
The final product obtained from both the above manufacturing processes will have similar physical and chemical properties except for the setting time and gain in strength. Rapid hardening Portland cement is manufactured by intergrinding of Ordinary Portland cement clinker with up to 15% gypsum or anhydrite or with up to 5% of CaCl 2, and 4-7% of finely ground blast furnace slag (or any pozzolanic material).
Applications of Rapid Hardening Cement:
Rapid hardening cement can be used for the following applications:
1. When larger volumes of concrete are needed in short span of time.
2. For precast products where demoulding has to be done early.
3. Can be used in cold weather concreting, where it is difficult to maintain high temperature and low relative humidity, as lower heat of hydration reduces risk of
Cement is the main ingredient in concrete. Concrete is used in the construction of roads, buildings, bridges and other structures. Concrete is used in many types of construction projects. There are several different types of concrete that are used in these projects. Cement is made from limestone and clay or shale. These materials are crushed and fed into a rotating kiln. The kiln heats to about 2,700 degrees Fahrenheit when the raw material is heated it moves from one end of the kiln to the other end of the kiln and by the time it reaches the end it has been transformed into clinker which looks like pellets.
The clinker is cooled and ground into a fine powder. The powder is mixed with gypsum to create Portland cement which can be mixed with water sand and gravel to make concrete or mortar. Concrete is also used to make sidewalks driveways floors foundations dams and many other things.
Concrete is an important building material for a variety of reasons. First concrete has a very long life span which makes it very cost effective for the building owner. Second concrete can be poured into forms that give it almost any shape imaginable making it very easy to use in construction projects. Third concrete can be colored so that it matches any color scheme desired
The manufacture of ordinary Portland cement (OPC) involves the following operations:
1. Quarrying of limestone and argillaceous material.
2. Crushing, stacking and reclaiming of raw materials in the correct proportion (the raw materials are now ready for the kiln).
3. Preparing the kiln feed.
4. Preheating, calcining and sintering in the rotary kiln.
5. Cooling, storing and grinding in the cement mill to produce ordinary Portland cement (OPC). Currently there are two basic production processes used in Ireland – the dry process, which is more commonly used, and the wet process which is mainly used by one producer in Ireland. Both methods require a long manufacturing time for OPC to reach its final strength due to slow hydration kinetics on account of low surface area of clinker phases such as C3S and C2S (which are responsible for strength development). The chemical composition of OPC can vary depending on raw materials used, but it consists mainly of tricalcium silicate (C3S), dicalcium silicate (C2S), tricalcium aluminate (C3A) and tetracalcium aluminofer