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घर की मजबूती को सीलन व्ह दरारों से बचाओ, Concrete Compaction

WHAT IS CONCRETE COMPACTION Compaction of Concrete is an operation in which fresh concrete is compacted in forms and make it encircle reinforcements and other embedded objects such as tubes in the mold. There are various problems that might arise if compaction of concrete is not carried out properly such as honeycomb and trapped inside concrete paste. Moreover, poor compaction of concrete could to permeability problems and therefore steel corrosion and decreasing ultimate capacity of hardened concrete. Methods of Compaction of Concrete Concrete consolidation can be carried out either by hand or machines. There are many factors that should be considered to choose compaction methods such as reinforcement quantities and spacing, concrete paste consistency and formwork complexity. Hand Compaction Method Reasonably workable and flowable concrete mixtures are consolidated by hand employing a rod. The bar should adequately reach the bottom of the form work and rode diameter need to compact concrete between reinforcement spacing and formworks. The concrete is tamped by the rod tool repeatedly to consolidate it. Mixtures with low slump value could be consolidated by hand if superplasticizers are added to decrease slump and make the concrete workable. Furthermore, tools such as spade is used to provide good surface appearance and hitting formwork sides make way to repel entrapped air out of the concrete. Mechanical consolidation is not recommended to use if the mixture is designed to compact by hand to avoid segregation. Mechanical Compaction Method #. Vibration Method of Concrete Compaction Vibration method is probably the most extensively used technique for compacting concrete. In this method, internal friction between aggregate particles is eliminated for a short time and concrete mixtures behave like liquid and gravitational force will come into effect. This lead to move entrapped air to move upward and the mixture will settle in the formworks. When the vibration is stopped, the internal friction is immediately developed again. Either number of vibrations per minute (vpm) or vibrations per second (Hertz) are used to express vibration. Compaction of concrete with vibrators is divided into the following types: a) Internal Vibrators Internal vibrators which sometimes called spude or poker vibrators are usually applied to compact concrete in beams, walls, columns, and slabs. Not only does vibrators performance is influenced by concrete workability but also by frequency, amplitude, and head dimensions of vibrators. Generally, vibrator head diameter is between 2-18 cm and the shape of the head is cylindrical. As the head diameter of vibrators is increased the effective action area is rose for instance radius action of vibrators with 4 cm head diameter is 15 cm while 45 cm is the radius action of vibrators with 8 cm head diameter. Moreover, it is considerably significant to utilize internal vibrators correctly to achieve the best compaction. Horizontal movement of vibrators should be avoided to prevent concrete segregation and lowering head of vibrators to the bottom of considered concrete layer and it should over lab previous layer by about 15 cm. Compacted concrete layer thickness is about the head length or 50 cm. Regarding using vibrators for compacting slabs, the vibrator must be kept submerged in concrete and this can be done by using it horizontally or at specific angle in addition to use 1.5 times the radius action as the distance to guarantee overlap previously adjacent vibrated layer. Not only does the vibrator should be held steady but also keep in specific station for 5-15 seconds to obtain desirable consolidation. The length of the time that the vibrator employed at the same station is based on concrete workability, force of the vibrator, and the nature of the element that is being compacted. Adequate internal vibration is decided by concrete surface modifications for example changes in coarse aggregate particles, general batch leveling and top surface appearance of thin film of mortar. In situations where vibrating concrete internally is not possible, it could be beneficial to vibrate the exposed part of reinforcement because it leads to remove entrapped air and water under reinforcement and increase the bond between concrete and steel. #Concrete #Compaction #Method CIVIL ENGINEER AVINASH SHARMA POSITIVE BUILDER    / @positivebuilder   घर की मजबूती को सीलन व्ह दरारों से बचाओ, Concrete Compaction positive builders,concrete compaction,How to do Concrete Compaction,Compaction of Concrete,Concrete compaction methods,Concrete Compaction,Compaction of concrete by hand,concrete ko compaction kyo karna hai,kyo bans se compaction nahi karna hai,compaction of concrete,compaction of concrete pdf,compaction of concrete ppt,importance of compaction of concrete,concrete compaction equipment,what is the compaction of concrete improves,compaction of concrete wikipedia