Cement plays an important role in the construction process. Therefore, before you buy, you need to know about the type of cement. It is the quality of the cement that determines the strength of the structure. Here we describe the use of different types of cement in construction.
This cement, also called the basic Portland cement, is ideal for use in common concrete structures that are not exposed to sulfate in soil or groundwater.
This cement is by far the largest produced than any other cement. It is manufactured by grinding Portland clinker, which may add up to 1% air entrainer with a small amount of gypsum, water, or both. This very useful type of cement.
Portland's clinker is composed of calcium silicate, a given homogeneous mixture of materials mainly containing 59%-64% lime (CaO) and 19%-24% silica (SiO2) and 3%-6%. Is heated to initially melt. Alumina (Al2O3) and 1% to 4% iron oxide (Fe2O3).
The hardening of the cement after adding water is due to the dissolution and reaction of the components.
Calcium aluminate first hardens and hardens, then comes calcium trisilicate (3CaO.2SiO2.3H2O). Calcium disilicate reacts slowly and contributes to strength at a later stage, usually in 14-28 days.
A typical chemical reaction is:
3CaO.Al2O3 + 6H20 → 3CaO.Al2O3.6H2O
(3CaO.SiO2) + 6H2O → 3 CaO.2SiO2.3H2O + 3Ca(OH)2
3 (2CaO.SiO2) + 6 H2O → 3CaO.2SiO2.3H2O + 3 Ca (OH) 2
Types of ordinary Portland cement
33 grade plain Portland cement
43 grade plain Portland cement
53 grade ordinary Portland cement
Portland Posolana Cement is prepared by grinding clinker and Posolana or blending Portland Cement with fine Posolana. The proportion of Pozzolana varies between 10% and 25% of the weight of cement.
PPC cement is suitable for the following conditions: It is also used for waterfront structures or offshore structures like dams, piers, thick foundations where mass concrete is used, sanitation systems such as sewers.
History behind PPC: The Romans and Greeks knew that if shredded and mixed with lime and sand, certain volcanic materials could be used to make excellent strength mortar. Roman builders used red or purple volcanic tuff found near the Gulf of Naples, especially around Pozzuoli. It is an excellent building material and has become known as Pozzolana. Today, it is a name that is often used to describe a variety of materials, both natural and artificial.
The main use of Pozzolana is to replace a percentage of the cement in the mix, which can have significant economic benefits, especially if the material is available locally.
Pozzolana is one of the siliceous substances, so it is not cementitious or binding, but it reacts with calcium hydroxide at the right temperature in the finely divided form in the presence of water to provide sufficient binding. Can form compounds with. Other natural volcanic materials with pozzolanic properties such as diatomaceous earth, calcined clay and fly ash.
Cement is made by intimately mixing calcareous and clayey and/or other silica, alumina, or iron oxide containing materials.
This cement has the same chemical composition as regular Portland cement, but is more finely ground. Its 24-hour strength is about the same as that achieved with normal Portland cement after 3 days. This cement allows for early removal of the shutter, which directly impacts time and cost savings.
It is commonly used in road construction and bridge construction, where the time factor is very important.
Extra rapid hardening cement is a suitable modification of quick-hardening cement. Manufactured by grinding calcium chloride with fast-setting Portland cement. Calcium chloride is usually mixed with 2% by weight of quick-setting cement. Since ultra-rapid cement is very sensitive, the concrete should be placed after transportation, placed, compressed and finished within 20 minutes after mixing. After the addition of water, a very large amount of heat is generated in a short period of time with hydration. Therefore, this type of cement is ideal for concrete in cold climates.
In Portland Slag Cement, blast furnace slag is a non-metal product consisting essentially of glass-containing silicates and lime aluminosilicates and other bases, which are developed simultaneously with iron in a blast furnace or an electric pig iron furnace. Grinded granular slag is obtained by further processing the molten slag by rapid cooling or quenching with water or steam and air.
This cement is prepared by intimately grinding Portland cement clinker and ground blast furnace slag (GGBF) slag, with the addition of gypsum and approved additives. The slag percentage must be between 25% and 65% of Portland slag cement. Slag, which contains oxides of lime, alumina, and silica, easily replaces the clay or shale normally used in the manufacture of Portland cement.
Hydrophobic cements are prepared from regular Portland cement clinker by adding certain water repellent chemicals during the grinding process. A water-repellent coating is formed on each particle of cement to prevent water and moisture from the air from being absorbed by the cement. This film breaks during concrete mixing and the normal hydration process works just like normal Portland cement.
This cement is ideal for long term storage in very moist climatic conditions. Hydrophobic agents include oleic acid, stearic acid and naphthenic acid. This cement is different from waterproof cement.
Since normal Portland cement is susceptible to sulphate, sulphate resistant cements were developed for use where the soil is sulphate infected.
In the case of cement due to sulphate attack at O.P.C., it can expand in the concrete frame, with cracks and subsequent fracture.
Many studies have found that cements with lower C3A content give better results in order to reduce the attack by sulfates. Sulfate resistant cement has a high silicate content and low C3A and C4AF.
Quick setting cement sets very quickly. This cement is used for aggressive basic conditions, such as where pumping is required or underwater land.
Fast-setting cement achieves fast-setting by reducing the gypsum content when crushing clinker. Quick setting cement is also used in some typical pouring operations.
This cement is obtained by grinding a high-alumina clinker consisting of monocalcium aluminate. High-alumina cement clinker is a selected mixture of materials containing mainly alumina (Al2O3) and lime (CaO), either fully or partially with a low proportion of iron oxide, silica (SiO2), and other oxides. Obtained by melting. High initial strength, high heat of hydration, and very high resistance to chemical attack are characteristics of high alumina cement. It is black in color. Its rapid hardening properties are due to the high proportion of calcium aluminate in place of the calcium silicate found in normal Portland cement.
The rapid heat generation of this cement is very advantageous when it is done in the weather where the concrete freezes. However, its use in hot climates is very limited due to increased porosity and hence reduced strength.
It is a hydraulic cement with less than 5% sulfuric acid (SO3) content and grinds a mixture of at least 7% blast furnace granulated slag, calcium sulphate and a small amount of lime or Portland clinker. This cement is used for marine construction, large amounts of concrete construction to resist aggressive water attacks, reinforced concrete pipes in groundwater, concrete construction in sulphate-containing soil, and chemical construction exposed to high concentrations of weak sulphate. A solution of mineral acid used in very serious conditions such as. It can also be used on the underside of railway bridges and sewers.
High alumina cements and supersulfated cements should only be used in special circumstances.
Masonry cement is obtained by mixing a mixture of Portland cement clinker and an inert material (non-pozzolan) with limestone and the like.
Agglomerates, dolomites, limestone, gypsum, and air-entrained plasticizers. Masonry cement has a slow hardening, high workability and high water retention, making it particularly suitable for masonry work.
Well cement is a special purpose cement that seals the space between a steel casing and a sedimentary rock by injecting a slurry into an oil well that has been drilled for oil. This cement prevents oil and gas from leaking out of the well. This cement also prevents sulfur gas and water containing dissolved salts. All these properties of oil well cements are obtained by adding a complex composition of cement with retarders such as starch and cellulosic products and acids.
Hydraulic cement, which sets the casing during oil well drilling and repair, under high pressure and high temperature of seal water and gas pocket, is suitable for use. In addition to coarse grinding, retarders are often included to meet the requirements of such uses, or reduce the tricalcium aluminate (C3A) content of the clinker.
Slurries of such cements need to be pumpable at elevated temperature and pressure for a sufficient period of time and then set very rapidly. This is a very convenient type of cement.
Colored cement is made by adding color-carrying pigments with Portland cement clinker. The pigment dosage is 5-10% of Portland cement. White or gray Portland cement is used as a matrix to achieve different colors. White Portland cement is manufactured similar to OPC.
Expandable cement is a type of cement that does not change in volume when dried. This type of cement also does not shrink during or after curing. This type of cement was developed using an expanding agent and a stabilizer.
Generally, sulfoaluminized clinker is mixed with Portland cement along with stabilizers. This cement is used to grout the foundation of anchor bolts or grout machines and grouts prestressed concrete ducts where volume changes are very sensitive to stability.
Air-entrained cement is made by adding an air-entraining agent in powder or liquid form using OPC cement clinker. Other external materials are added animal and vegetable fats, oils and other acids, including aluminum powder, certain wetting agents such as hydrogen peroxide, and the introduction of air entraining agents to harden concrete. Improves frost resistance. By using this cement, the workability, segregation, and bleeding properties of concrete are improved.