Common applicable codes around the world such as ACI Code, European Code, British Standards, Canadian standard association, and Indian standard have provided a formula for the computation of elastic modulus of concrete. The dynamic modulus is used to determine the relative durability of concrete when exposed to severe climatic conditions as the dynamic modulus of concrete changes with the quality of concrete. It quantifies the relationship between tensile stress (force per unit area) and axial strain (proportional deformation) in the linear elastic region of a material and is … Modulus of elasticity for normal weight concrete based on Canadian Standard Association (CSA A23.3): Modulus of elasticity of concrete based on Euro code can be evaluated using the following expression: fcm: mean compressive strength of concrete at 28 days according to Table 3.1 BS EN 1992-1-1: 2004. The results showed that the strength and elasticity modulus of plastic concrete increase with the increase of cement factor and decrease of bentonite content. Modulus of Elasticity Based on ACI 318-14, 4. The modulus of elasticity so obtained from actual loading is called static modulus of elasticity. Plane cross sections continue to be plane after bending. The deformation of concrete depends upon the magnitude of the load, the rate of applying the load and the time elapsed after which the observations are recorded. © 2009-2020 The Constructor. Thus the relation between the modulus of elasticity of concrete and its strength depends on age. In this case no stress is applied on the specimen. Modulus of elasticity of concrete is sensitive to aggregate and mixture proportions of concrete. In this article we will discuss about:- 1. From the known values of length of specimen, density of concrete and resonant frequency the value of dynamic modulus in S.I. Structural components still must be able to withstand dead and live loads without collapse even though the rise in temperature causes a decrease in the strength and modulus of elasticity for concrete and steel reinforcement. Uploader Agreement. The modulus of elasticity of concrete increases more rapidly with age than the strength of concrete. In the second operation, the reading of the ext­ensometer is noted and it is again loaded till the load reaches to 1/3rd of the cube strength plus 1.5 kg/cm2. It has been observed that richer mixes have higher modulus of elasticity of con­crete i.e., higher the amount of cement; higher the modulus of elasticity. [gravityform id="1" title="false" description="false" ajax="true"]. Perhaps this is due to the deve­lopment of fine or micro cracks at the interface of the aggregate and cement paste. Now this load is sustained for 1 minute. The value of strain is calculated by dividing the gauge read­ings by gauge length. Furthermore, a parametric study has been done to investigate the influence of mix design on these materials. Not only does it demonstrate the ability of concrete to withstand deformation due to applied stress but also its stiffness. Login to The Constructor to ask questions, answer people’s questions, write articles & connect with other people. Actually none of these assumptions is strictly true and concrete is not perfectly elastic material. This method is very useful to determine the quality of concrete, when it is subjected to alternate freezing and thawing. The value of modulus of elasticity Ec determined by actual loading of concrete is known as static modulus of elasticity. The modulus of elasticity of light weight aggregate concrete usually varies from 40 to 80% of the modulus of normal weight concrete of the same strength in fact it is similar to that of cement paste. Modulus of elasticity = unit stress/unit strain. Prohibited Content 3. The cylinder is loaded with the standard rate and at the end of each interval the reading of extensometer noted. Copyright 10. Modulus of Elasticity of Concrete- Determination and Importance in Design, Calculation of Elastic Modulus of Concrete, 1. Though concrete is not an elastic material in true sense, yet within limits it is considered an elastic material. Finally, knowledge of the modulus of elasticity of high strength concrete is very important in avoiding excessive deformation providing satisfactory serviceability and avoiding the most cost-effective designs. The difference between the strains of second and third observations should not be more than 5%. How can we use magnetic levitation method in civil engineering? 25%STEEL. The strain of wet concrete is found less than for dry concrete, hence the modulus of elasticity is higher for wet concrete than for dry concrete. The concrete damaged plasticity model assumes that the reduction of the elastic modulus is given in terms of a scalar degradation variable d as E = ( 1 - d ) ⁢ E 0 , where E 0 is the initial (undamaged) modulus of the material. The shear or modulus of rigidity (G) describes shear when an object is acted upon by opposing forces. The influence of moisture condition at the time of test for secant modulus at different ages is shown in Fig. Concrete modulus of elasticity based on Indian standard can be calculated using the following expression: It is highly crucial to define modulus of elasticity of concrete in the design of concrete structure. Linear analysis of elements, which is based on the theory of elasticity, is used to satisfy requirements of both ultimate and serviceability limit state for instance in the case of pre-stressed concrete that demonstrate uncracked section up to the failure. The static modulus of elasticity does not represent the true elastic behaviour of concrete due to the phenomenon of creep. Huge Collection of Essays, Research Papers and Articles on Business Management shared by visitors and users like you. These strains are plotted against stress as shown in Fig. It is represented by the slope of a tangent to the stress-strain curve drawn passing through the origin. VIP members get additional benefits. Report a Violation 11. This method of testing is known as destructive method as the specimen is stressed or loaded till its failure. Secondly it is difficult to determine tangent modulus with accuracy as the tangent to the curve is drawn by the eye judgment. It is represented by the slope of a line drawn from the origin to any point C on the curve. At the time of design of a reinforced concrete structure, it is assumed that the bond between concrete and steel is perfect and the stress in steel is ‘m’ times the stress in concrete, where m is the ratio of modulus of elasticity of steel and concrete. A spring is an example of an elastic object - when stretched, it … The concrete composite is then in the range of 30 to 50 GPa. For light weight concrete relation is-, It has been observed that for the same stress-strength ratio, the stronger the concrete, higher the strain, On the contrary stronger the concrete higher the modulus of elasticity. Terms of Service 7. The elastic modulus of the hardened paste may be in the order of 10-30 GPa and aggregates about 45 to 85 GPa. Young's modulus, the Young modulus or the modulus of elasticity in tension, is a mechanical property that measures the tensile stiffness of a solid material. Bone is a remarkable exception. modulus synonyms, modulus pronunciation, modulus translation, English dictionary definition of modulus. This relationship may serve as a basis for the estimation of strength (or modulus of elasticity… Higher strengths give higher value of modulus of elasticity. Which means that the higher the E-module in concrete, the … This relation is not applicable to very rich concrete with cement content more than 500 kg/m3 and light weight concrete. ... Types of Foundation for Buildings and their Uses [PDF], Methods of Rainwater Harvesting [PDF]: Components, Transport, and Storage, Compressive Strength of Concrete -Cube Test [PDF], Procedure, Results, Standard Size of Rooms in Residential Building and their Locations, 16 Types of Heavy Equipment Used in Construction, Major Problems in Concrete Pumping Works: How to Avoid Them? The modulus of elasticity of concrete is relatively constant at low stress levels but starts decreasing at higher stress levels as matrix cracking develops. Stress-strain curve for various mix proportioned concrete are shown in Fig. Its shear modulus is not only greater than its Young’s modulus, but it is as large as that of steel. You will receive a link and will create a new password via email. :36 Value of modulus of elasticity for some materials Material Modulus of elasticity [GPa] aluminium and its alloys 65 - 73 ceramics 8 - 12 concrete 15 - 40 copper 125 diamond 1000 lightweight concrete 0,8 - 2 low alloy steels 200 - 210 polystyrene 3,2 - 3,5 silica glass 60 - 90 What are the purposes for building dams in semi-arid regions. Note 4: If circumstances warrant, a velocity-strength (or velocity-modulus) relationship may be established by the determination of pulse velocity and compressive strength (or modulus of elasticity) on a number of specimens of a concrete. The computation of modulus of elasticity of concrete using equations of various codes are presented below : According to ACI 318-14 section 19.2.2, the modulus of elasticity of concrete is evaluated as follows : For concrete, the unit weight(wc) ranges from 1440 to 2560 Kg per cubic meters. Modulus of elasticity E cm The elastic deformation properties of reinforced concrete depend on its composition and especially on the aggregates. The designed MST-BAR® deliver extremely high bond strength with concrete (x3 of the one with the steel) while providing the highest stiffness in a material. The deflection of a concrete slab under a Falling Weight Deflectometer (FWD) ... Key word: Maize, bending stress, modulus of elasticity, shearing stress, specific shearing energy. In case of concrete, it deforms on the application of load, but this deformation does not follow any set rule. This lower strain gives the higher values of modulus of elasticity. The relationship between the modulus of elasticity and strength is not much affected by the temperature upto 230°C as both these properties vary with temperature in the same way. But the stress-strain curve of concrete, which is a combination of aggregate and cement paste gives a curved curve. Sign Up to The Constructor to ask questions, answer questions, write articles, and connect with other people. As it is the case for the compressive strength, Young's modulus … Modulus of Elasticity Based on British Standard, Importance in Design of Concrete Structure, Tension Test on Steel Rod – Procedure and Results, Determination of Elastic Modulus of Concrete in Accordance with ASTM C469. pH = chemical alkalinity P = name for load or axial force vector P o = maximum axial force with no concurrent bending moment in a Which instrument is widely used for surveying? Privacy Policy 9. (Universal test­ing machine) and measuring the strains or deformations by strain gauges or dial gauges fixed at certain gauge length. Find the moment capacity of the beam. The reading of extensometer is noted and the load released slowly till it reaches to a value of 1.5 kg/cm2 on the cylinder specimen. Modulus of elasticity for all grades of steel is taken as Es = 29 x 10 6 psi. Similarly the curve of stress-strain of cement paste alone shows a fairly good straight line. Actual measured values may differ ± 20% from the values obtained from the above relation. The relation between static and dynamic modulic is given by the following relation in G.N/m2. All Rights Reserved. Taking into account the effects of creep and shrinkage partially IS code gives the following expression for the long term … Lost your password? As concrete is an imperfect elastic material, stress strain diagram is a curved line. In international system of units, (SI units) the unit of modulus of elasticity is GPa. The modulus of elasticity is determined by subjecting the specimen to longitudinal vibration at their natural frequency that is why this is known as dynamic modulus. Please note that the higher the E-module, the higher peak stresses will become! Video Included, Preliminary Activities for Carrying out Riveting and Bolting, 13 General Items of Work for Building Cost Estimation. On the other hand if the curve is as shown in Fig.15.2 then the material is not perfectly elastic. for normal weight concrete. The modulus of elasticity of concrete is used in the calculations of structural deformations. Please enter your email address. ARCH 331 Note Set 22.1 Su2014abn 2 n = modulus of elasticity transformation coefficient for steel to concrete n.a. ACI 318–08, (Normal weight concrete) the modulus of elasticity of concrete is , Ec =4700 √f’c Mpa and; IS:456 the modulus of elasticity of concrete is 5000√f’c, MPa. Major Problems in Concrete Pumping Works: How to Avoid Them? In addition to compute deflections which are required to be limited under the serviceability requirements in all structures. Thus the stress-strain curve continues to bend faster than the increase of stress. The value of Elastic modulus at 28 days of concrete age is given in BS 8110: Part II 1985: ko: is 20 KN per square millimeter At higher stresses the modulus of elasticity is affected more seriously. By slowing down the rate of loading i.e., by increasing the time of loading from 5 seconds to about 2 minutes, the increase in the strain is found to go up by 15%, but at normal rate of loading, normally 2 to 10 minutes time is required to test a specimen in an ordinary testing machine, the increase in strain is very small. = shorthand for neutral axis (N.A.) This failure of bond at the interface increases at a faster rate than that due to applied stress. The modulus of elasticity of concrete is used in the calculations of structural deformations. It is represented by line OA in the Fig. This method is most practical and is in most general use as it represents the actual defor­mation at the selected point and no uncertainties are involved in its determination. 15.4. 15.5. (Gega Pascal), ISI-456-2000 has suggested the relation between static modulus of elasticity Ec and the characteristic strength of concrete as follows-. Following factors affect the value of modulus of elasticity: It is one of the most important factors which affect the modulus of elasticity. A good, normal concrete mixture has an E-modulus of 25.000-30.000 N/mm2. Elasticity is a property of an object or material indicating how it will restore it to its original shape after distortion. Thus a non-destructive method of testing known as dynamic method is adopted for determining the modulus of elasticity. Concrete Technology, Concrete, Properties, Elasticity, Modulus of Elasticity of Concrete. The modulus of elasticity in tension is equal to the modulus of elasticity in compression. It can also be defined as the change of stress with respect to the elastic strain and may be computed by the following relation. In order to calculate the deflection of structures and design of concrete members with respect to their sections, quantity of steel etc., the knowledge of deformation properties is necessary. Stress-Strain Relationship of Aggregate and Cement Paste: The curve drawn between stress and strain of aggregate alone is found a fairly good straight line. Some values of modulus of elasticity are shown in Table 15.1: In SI units Ee = 9.1 (fck)1/3 for concrete density 2320 kg/m3. It is a measure of volumetric elasticity, calculated as volumetric stress divided by volumetric strain. In the third cycle, the load from zero position to 1/3rd of the cube strength plus 1.5 kg/cm2 is divided into 10 intervals. Content Filtration 6. Modulus of elasticity of concrete(Ec) is defined as the ratio of the applied stress to the corresponding strain. f’c = Compressive strength of concrete. The main factors which may affect the values determination of modulus … For example, shear moduli are less than Young’s moduli for most materials. The accuracy of design will depend upon the value of modulus of elasticity of concrete, as the modulus of steel more or less is a definite quantity. A stress-strain curve is drawn with the help of values of stress and strain obtained. This ratio is known as modular ratio. It is represented by the slope of the line drawn tangent to the stress-strain curve at any point on the curve, but this modulus applies only to very small changes in load above or below the load at which the tangent modulus is considered. 15.5. Approximate values for the modulus of elasticity E cm (secant value between σ c = 0 and 0.4 f cm ) for concretes with quartzite aggregates, are given in EN1992-1-1 Table 3.1 … Bones can support loads comparable to that of concrete and … The American Concrete Institute. We would like to show you a description here but the site won’t allow us. In other words, it reflects the ability of concrete to deflect elastically. The magnitude of the observed strains and the curvature of the stress-strain relation depend on the rate of application of stress. Disclaimer 8. units is determined from the relation-, If length of specimen is measured in mm and density ρ in kg/m3 then-, The value of dynamic modulus of elasticity can also be determined from the relation-, Ed = ρv2 [(1 + µ)(1 – 2µ)/(1 – µ)]. Plagiarism Prevention 5. In this method the extensometer is fixed on a 15 cms x 30 cms cylinder and placed in compression testing machine and loaded at a rate of 140 kg/cm2 per minute. When the load is applied extremely rapidly, the recorded strains are greatly reduced and the curvature of stress strain curve is reduced to a very small value. The modulus of elasticity of concrete may be measured in compression, tension or shear. What is piping technology for termite treatment in building? Elastic modulus of concrete can be classified into two main groups as: The strains obtained as above are plotted against stress and a curve is obtai­ned as shown in Fig. 15.3. The stress in the elastic range is equal to the strain multiplied by Es. Definition of Modulus of Elasticity 2. Steam cured concrete has slightly lower modulus than water cured concrete of the same strength. Founded in 1904 and headquartered in Farmington Hills, Michigan, USA, the American Concrete Institute is a leading authority and resource worldwide for the development, dissemination, and adoption of its consensus-based standards, technical resources, educational programs, and proven expertise for individuals and organizations involved in concrete …

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