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Which cement is better OPC cement or PPC cement?
Well, both types of cements have got merits of its own. OPC is a pure type cement releasing heat energy at a faster rate & the chances of shrinkage cracks are higher. PPC is a low heat cement in comparison to OPC requiring lesser degree of immediate post concrete setting curing. OPC is not suitable for hot weather conditions. PPC is suitable for adverse weather conditions. OPC cannot be used for thick & massive elements. PPC is to some extent suitable for thicker elements. Temperature controls are better conducted on PPC.
What are the factors that effects the normal consistency of a cement?
following factors which affects the consistency of cement:- 1. fineness of cement 2. temperature. 3. method of mixing water . 4. %of admixtures in cement (flyash in case of PPC) 5. w/c ratio
Difference of Sodium and calcium lignosulfonate in concrete application?
Calcium lignosulfonate in concrete action and dosage - Stone Refractories I. Calcium lignosulfonate water reduction in concrete reinforced role Calcium lignosulfonate and sodium lignosulfonate reducing agent is a surface-active agent, added to the concrete, due to the orientation of hydrophobic groups adsorbed on the surface of cement particles, so that the cement with a negative charge. Cement particles have the same charge in the charge repulsion exclusion from each other under the action of dispersion of cement in water the initially-formed into a dispersion structure floc structure, flocculation cohesion body of free water is released, so as to achieve the purpose of reducing agent. Observations show that lignin added to the concrete after mixing for 5 minutes more than 80% of the reducing agent is adsorbed, clearly visible under the electron microscope, the center point of significantly increased hydration, hydration evenly distributed, hydrated crystal fibers longer various microscopic characteristics. Thus, the adding of calcium lignosulfonate, leaving the pores free water evaporation is small, dense internal structure, that is, reduction of the porosity is clearly beneficial to increase the strength of concrete, cement improves the size and distribution of the pore structure conditions, the crystal growth rate slow, crystal growth more fully, and thus get more fibrous crystals interspersed with each other to form a strong network structure, so that the concrete strength significantly increased. Therefore, in concrete mixed with lignin superplasticizer, concrete mixture can reduce water consumption and reduce water-cement ratio, improved workability, is conducive to pumping, improve concrete strength, density and durability. Second, the lignin water reducer in concrete dosage and key performance indicators 1, to improve concrete performance: When the same amount of cement, concrete slump similar to the blank can reduce water consumption by 10-15%, 10-20% increase in 28-day strength, a strength of about 10%. 2, saving cement consumption: When the concrete strength and slump similar, can save about 10% of cement, use one ton of cement water reducing agent can save 30-40 tons. 3, to improve the workability of concrete: When the amount of cement concrete and water consumption constant, low plasticity of concrete slump can be increased about twice (by a 3-5cm up to 8-18cm), early strength and undoped who was close. 4, lignin retarding effect: 0.25% lignin superplasticizer mixed after the slump in keeping basically the same, the initial setting time 1-2 hours delay ordinary cement, slag cement 2-4 hours, and finally 2 hours setting time of portland cement, slag cement 2-3 hours, if not reduce water consumption and increase the slump, or when the slump while maintaining the same amount of cement used to save, then the setting time delay greater extent than less water greater. 5, can reduce early hydration heat: exothermic peak are longer than the delay undoped, about 3 hours of Portland cement, slag cement about 8 hours, 11 hours or more concrete dam, the exothermic peak maximum temperature and not miserable by comparison, ordinary cement is slightly lower, slag cement and cement dam were lower than 3 ℃ 6, concrete air content increased: blank concrete air content of about 1%, 0.25% lignin mixed concrete air content of 2.3 percent. 7, the bleeding rate decreased: in concrete slump basically the same case, the doped lignin bleeding rate than those who are not doping can be reduced more than 30%, while maintaining the same water-cement ratio, increasing slump situation , it is also due to the introduction of air lignin hydrophilic and other reasons, the bleeding rate. 8, shrinkage performance: initial (1-7) days compared with non-water-reducing admixture, was close to or slightly decreased, 28 days and late (except saving cement above), a slight increase, but the increase values ​​did not exceed 0.01% (0.01mm / m). 9, to improve the density of concrete, improve concrete impermeability. By the B = 6 grade up to B = 12-30 level. 10, no chlorine salt, no corrosion of steel hazards. Usage of lignosulfonates on the base of sodium, relating to the hydrofilizing plastificators, at the concrete manufacture and dry construction mixtures lets to reduce the consumption of components up to 10-15%. Demixing of the concrete mass reduces and its solidity rises, the speed of hardening slows down. They insert additives of lignosulfonates in the quantity of 0,15-0,20%, it is necessary to insert superplastificators from the mass of dry substance in the quantity of 0,5-2,0% from the mass of dry concrete. When replacing superplastificators by lignosulfonates the solidity of concrete rises up to 20-25%, freeze resistance - in 3-4 times and the cost of mixtures reduces cause of adding of small amount of lignosulfonates, what is connected with their adsorbtion on the surface of hard phase. Usage of lignosulfonates reduces humidity of raw mud if conserving its flow behavior, what rises the manufacture of stove and reduces specific flow volume to the burning of clinker. With the usage of intensifier on the base of lignosulfonates the production of grinding units rises and there is an opportunity to change expensive and deficit chemical products. more information please visit:www.greenagrochem.com
What is curing of concrete?
The curing of concrete is a reaction between the type of cement in the concrete and the water. This reaction between cement and water is known as hydration. When the concrete sets and gains strength through this process it is known as curing. Test cylinders of concrete for construction projects are placed in a curing room where they are continuous misted with water at 23 +-2 degrees Celsius for 7 and 28 days before testing. This provides adequate curing.
What is the hourly rate for a cad technician?
$45-50 per hour
What is the rate of cement?
225
What is coverage rate?
Monthly price for coverage in question.
Difference between ordinary Portland cement and puzzalona Portland cement?
OPC - Ordinary Portland cementOPC - Materials used - Argillaceous and calcareous materialsPPC - Portland Pozzolona CementPPC - OPC + Pozzolonoc materials(fly ash, volcanic ash, pumicite at the time of grinding).
What is the rate of priya cement?
180
What the rate of one bag of cement?
225
What is the rate of kcp cement in hyderabad?
270
How much 1 bag acc cement in India?
how much 1 bag acc cement rate in mumbai
What does the fineness of the cement indicate?
That indicates higher hydration rate of the cement , thus faster to achieve the desired resistance.
Fine grained material used in cement?
The fineness of cement has an important bearing on the rate of hydration and hence onthe rate of gain of strength and also on the rate of evolution of heat. Finer cement offers agreater surface area for hydration and hence faster the development of strength.
How do you calculate cement for building project?
Dimensions x whatever is the going rate at your local cement contracter... usually by the square foot
How many shovels in a bag of cement?
there is 5 shovels full in a 25kg bag of cement
What is current cement rate in kerala?
Rs. 380 (50 Kg)
