Characteristics of an ideal reinforcing material

Content of this article : Characteristics of an Ideal Reinforcing Material,Steel as Reinforcing Material has high tensile strength and elasticity.,Deformed Bars and Twisted Bars Characteristics of an Ideal Reinforcing Material The characteristics of an ideal reinforcing material are: It should be easily and cheaply available in bulk. It should possess high tensile stress and elasticity. Its thermal coefficient of expansion should be nearly equal to that of concrete to minimise thermal stress. It should have a long and durable life so that it can render service for longer time. It should be free from loose mill scales, loose rust and coat of paints, which reduce the bond. It should be capable of forming perfect bond or grip with concrete so that stresses are transferred from one material to the other.    Steel as Reinforcing Material The steel is commonly used as reinforcing material due to its following qualities. It possesses…

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ADVANTAGES AND DISADVANTAGES OF CONCRETE

ADVANTAGES AND DISADVANTAGES OF CONCRETE Content of this article: Advantages of concrete,Disadvantages of concrete,advantages and disadvantages of concrete,inert material acts as a filler and the binding materials.Rcc Concrete is considered as a chemically combined mass where the inert material acts as a filler and the binding materials act as a binder. The most important binding materials are cement and lime. Inert materials used in concrete are termed as aggregates. Most common aggregates are sand, brick chips, stone chips, gravels, shells etc. The concrete plays a very important role in all branches of civil engineering. Concrete is an inexpensive, quick and durable way to complete many construction projects. However, there are advantages and disadvantages associated with this material. For example, while concrete becomes stronger and more durable with time, it is susceptible to water and freezing temperatures, meaning that water can seep into cracks and cause damage to the concrete. There…

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Properties of concrete in plastic and hardened state

Contents of this article:properties of concrete in plastic state,properties of concrete in hardened state,concrete in setting state,workability,water cement ratio. Properties of Concrete in Plastic State concrete in Plastic State When the concrete is first mixed it is like bread dough . It is soft and can be worked or moulded into different shapes. In this state concrete is called PLASTIC. Concrete is plastic during placing and compaction. The most important properties of plastic concrete are workability and cohesiveness. Properties of Concrete in Hardened State   concrete in Hardened State After concrete has set it begins to gain strength and harden. The properties of hardened concrete are strength and durability. Hardened concrete will have no footprints on it if walked on.     concrete in Setting State   Concrete then begins to stiffen. The stiffening of concrete, when it is no longer soft, is called SETTING. Setting takes place after compaction…

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Equivalent and effective Lengths of Columns

The effective column length can be defined as the length of an equivalent pin-ended column having the same load-carrying capacity as the member under consideration.The smaller the effective length of a particular column,the smaller its danger of lateral buckling and the greater its load carrying capacity. It must be recognized that column ends in practice are neither perfectly fixed nor perfectly hinged. The designer may have to interpolate between the theoretical values given, to obtain a sensible approximation to actual restraint conditions.   Equivalent Lengths of Columns for Various End Conditions S.No. Type Effective Length of member I 1. Effectively held in position and restrained in direction at both ends. 0.67L 2. Effectively held in position at both ends and restrained in direction at one end. 0.85L 3. Effectively held in position at both ends but not restrained in direction L 4. Effectively held in position and restrained in direction…

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Definition and object of Surveying and levelling

Definition and object of Surveying and levelling Learn Surveying, definition of surveying,Definition of levelling, Object of Surveying Definition of Surveying Surveying is the art of determining the relative positions of points on, above or beneath the surface of the earth by means of direct or indirect measurements of distance, direction and elevation. It also includes the art of establishing points by predetermined angular and linear measurements. The application of surveying requires skill as well as the knowledge of mathematics, physics, and to some extent, astronomy. Definition of Levelling Levelling is a branch of surveying the object of which is (i) to find the elevations of points with respect to a given or assumed datum, and (ii) to establish points at a given elevation or at different elevations with respect to a given or assumed datum. The first operation is required to enable the works to be designed while the second…

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FUNCTIONS AND TYPES OF FOUNDATIONS

Learn FUNCTIONS AND TYPES OF FOUNDATIONS,foundation,types of foundation,spread foundation,pile foundation,friction pile,end bearing pile Foundation The lowest part of a structure which transmits the weight of the structure together with live loads, seismic and wind pressure to the ground surface on which the structure rests, ensuring its safe bearing capacity, is called foundation. To increase the stability of the structure, foundations are generally placed below the ground level. Functions of Foundations Following are the main functions of foundations : To transmit and distribute the total load of the struc­ture to a larger area of underlying support. To prevent differential settlement of the structure. To provide stability to the structure. Types of Foundations The following are the main types of foundations : Spread Foundations. The total load of the structure transmitted to the base of the structure is spread over a large area by a spread foundation. The width of the wall…

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GROWTH OF TIMBER TREE AND ITS STRUCTURE

In This article Learn growth of timber,timber,sap wood,annual rings,cambium layer,uses of timber,classification of trees,growth of timber tree and its structure. TIMBER    DEFINITION Wood suitable for building or other engineering purposes is called timber. When it forms part of a living tree it is called standing timber. When the tree has been felled it is called rough timber. When it has been sawn to various market forms such as beams, battens and planks etc., it is called converted timber.     USES OF TMBER Timber is used for the following categories of works : (i)        For construction purposes, including building construction, houseposts, beams, rafters, bridges, piles, poles and railway sleepers etc. (ii)       For furniture and cabinet making. (iii)     For light packing cases. (iv)      For heavy packing cases (for machinery and similar stores). (v)       For manufacturing agricultural implements and tool handles. (vi)      For making turnery articles and toys etc. (vii)    For…

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SEASONING OF TIMBER AND ITS METHOD

In this article learn seasoning of timber,air seasoning or natural seasoning,kiln seasoning or artificial seasoning,object of seasoning,methods of stacking, seasoning methods, Preventing drying of logs,comparison of air seasoning and kiln seasoning. SEASONING OF TIMBER Newly felled tree contains a considerable quantity of sap. If this sap is not removed the timber is likely to warp, crack and shrink. It may even decay. The art of seasoning of timber is to extract the moisture under controlled conditions as nearly as possible at a uniform rate from all parts of timber and to leave the remaining moisture, that cannot be extracted, uniformly distributed throughout the mass. Irregular drying will cause irregular shrinkage resulting in the setting up of internal stresses between the fibres. When these stresses become strong enough to overcome the cohesion of the fibres then the timber warps and shakes are formed.  Objects of seasoning. (i) Wet timber is an…

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Workability of concrete and Compaction factor test.

In this article Learn : Workability of concrete and Compaction factor test. WORKABILITY OF CONCRETE It is the amount of work required to place concrete and to compact it thoroughly. Workability of concrete increases with the addition of water but it reduces the strength and as such it is not a very desirable way of increasing the workability. Use of aggregates which are round and have smooth surfaces increases the workability. Keeping the cement, aggregates ratio the same if the quantity of coarse aggregate is increased then the workability improves. Workability could also be improved by adding Air-entraining agents such as Vinsol resin or Darex etc. Use of Lisapole liquid at the rat of 30 c.c. per bag of cement improves not only the workability but also the water tightness of concrete. Slump test gives an idea of only the flowing property of wet concrete and not of the workability.…

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Water cement ratio and slump test

In this article Learn : Water cement ratio and slump test Water cement ratio : It is the ratio of water and cement (by weight or by volume) used in the preparation of concrete. The quantity of water used in mixing concrete is very important. If the percentage of water used is less then there shall not be sufficient quantity of water to hydrate cement. It shall result in porous and weak concrete. However, the usual tendency is to use too much water which gives a more workable mix but it does not give sound concrete. Too much of water results in segregation of aggregates and gives porous concrete of low strength and low density. (Fig. 8.1.).   A certain minimum proportion of water is necessary in order to hydrate the cement completely. To make the concrete sufficiently workable to be placed in position some more water is needed. So…

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