Concrete technology 11 factors affecting the selection of repair materials 11 factors affecting the selection of repair materials there are a number of factors such as strength, durability, thermal coefficient of thermal expansion, permeability, low dry shrinkage, chemical and electrical properties, curing, and cost that must be considered to select the most appropriate. The thesis aims to describe and evaluate the important factors that affect the final value of concrete modulus of elasticity, especially those that can be influenced during construction. The concrete technology notes pdf ct notes pdf book starts with the topics covering portland cement, mineral and chemical admixtures, classification of aggregate, factors affecting workability, water cement ratio, compression tests, factors in the choice of mix. If cement is reduced, then at fixed wc ratio the workability will be reduced leading to inadequate compaction. The elastisitymodulus or emodulus is a property of a material like concrete or steel whichs tells how much tension is needed to make it a little bit longer or shorter when you pull at 2 ends of a steal beam itll be a bit longer then when you press it together.
Moreover, because of the stressstrain characteristics of concrete, it is probable that the modulus of elasticity of concrete, regardless of how it is determined, is a function of the stress intensity. Factors affecting deflections of rcc beams and slabs. Factors affecting the modulus of elasticity of concrete. In turkey, many existing reinforced concrete buildings are in urgent need of seismic retrofitting.
The relationship between modulus of elasticity, e, and the product of compressive strength to the power and unit weight to the sec. An evaluation of factors affecting the tensile properties of. Properties of hardened concrete strength, sjrinkage, creep. Pdf key factors affecting the compressive strength of. Results of experiments on the influence on shear strength of the size of the compression zone of the beam and of hooks on plain and deformed bars are presented. The technical and scientific knowledge of the physical and mechanical behavior of concrete with recycled aggregates is not well established, and this is a knowledge gap, especially considering the use in structural elements.
Some factors in the shear strength of reinforced concrete. Several of the numerical approximations presented for the stressstrain diagram can take some of these effects into consideration. Factors affecting workability of concrete civil engineering. Here you can download the free lecture notes of concrete technology pdf notes ct pdf notes with multiple file links to download. What are the factors affecting young modulus of elasticity. Factors affecting the modulus of elasticity of concrete may 23, 2018 by kathir leave a comment since concrete is a multiphase solid, no direct relationship can exist between its density and modulus as in singlephase solids such as metals. Youngs modulus of concrete depends on many other factors such as moisture, the. How to fit a concrete cylinder with compressometerextensometer for elasticity modulus test duration. For a more realistic interstory ratio prediction, the modulus of.
When a load is applied to concrete, it experiences an instantaneous elastic strain which develops into creep strain if the load is sustained. Mar 09, 2017 modulus of elasticity of concrete as per is 456. Sep 16, 20 civildigital powerpoint presentations building technology what are properties of hardened concretegoverning factors properties of hardened concrete properties of hardened concrete are explained on the basis of its strength and performance under various types of force actions and conditions. Any concrete pavement, built of any thickness, will. Concrete modulus of rupture is more changeable than compressive strength. Physically it indicates a materials resistance to being deformed when a stress is applied to it. The primary objective of this study is to investigate the effect of cylinder size 100 by 200 mm and 150 by 300 mm on empirical equations that relate static and dynamic elastic moduli of concrete and static elastic modulus and compressive strength of concrete.
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 consensusbased standards, technical resources, educational programs, and proven expertise for individuals and organizations involved in concrete design. A parametric study was conducted to explore the effect of the interfacial transition zone itz or interphase on the overall elastic modulus of the cntreinforced cement. Properties of hardened concrete strength, sjrinkage. Modulus of elasticity also known as elastic modulus, the coefficient of elasticity of a material is a number which is defined by the ratio of the applied stress to the corresponding strain within the elastic limit. As a consequence, such models can only be used to evaluate the effects produced by the concrete components on the modulus of elasticity.
For the pairs of prisms tested on each occasion, standard deviations were calculated. Creep does not necessarily cause concrete to fail or break apart. Elasticity modulus, shrinkage, and creep of highstrength. Therefore, the manufacture should choose the material in such a way that it should regain its elastic property even when it is subjected to large number of cycles of stress. Pdf this contribution aims to highlight, from an experimental point of view, the key factors affecting the compressive strength of foamed concrete. Modulus of rupture modulus of elasticity modulus of subgrade reaction 198693 rigid pavement design equation. Modulus of elasticity results of dynamic e tests are given in table 4, for water cured prisms, with 10% sf. Modulus of elasticity of lightweight concrete containing. Many factors have been shown to influence the flexural tensile strength of concrete, particularly the level of stress, size, age and confinement to concrete flexure member, etc. The effect of interfacial transition zone properties on. Modulus of elasticity of concrete the modulus of elasticity of concrete e c adopted in modified form by the aci code is given by with normalweight, normaldensity concrete these two relations can be simplified to where e c modulus of elasticity of concrete, lbin 2 mpa. It is defined as ratio of normal stress to longitudinal strain within the limit of proportionality.
Factors in the choice of mix proportions bis and aci methods of mix design. The modulus of elasticity young s modulus e is a material property, that describes its stiffness and is therefore one of the most important properties of solid materials. The mechanism of geopolymerisation may consist of dissolution, transportation or orientation, and. In recent years building specifications have even required a specific elastic modulus of concrete to be met, mostly to. A practical equation for elastic modulus of concrete. The results show that the curing method strongly affects not only the development, but. Standard cylinder 150x300 mm or 150x100 cube with aggregate size of which is not exceeding 25mm is used to determine the strength. The objectives of this study are to investigate the relationship between static and dynamic elastic moduli determined using shearwave velocity measurements and to demonstrate the practical potential of the shearwave velocity method for in situ dynamic modulus evaluation. Modulus of elasticity of concrete is a key factor for. Pdf evaluation of elastic modulus reduction due to asr. Procedure for measuring the modulus of elasticity of concrete cores and cylinders rev. Aci committee 469, standard test method for static modulus of elasticity and poissons ratio of concrete in compression, american concrete institute, farmington hills, mich, usa, 2014.
Estimation of the static modulus of elasticity of concrete using the impulse excitation technique itc07 atcp. Parameters affecting the modulus of elasticity of concretes the elastic properties of concretes largely depend on the properties of their components. Modulus of elasticity iof concrete affected by elastic moduli. Factors affecting price elasticity of demand economics. Modulus of elasticity of concrete ec is defined as the ratio of the applied stress to the corresponding strain. Shrinkage deformation affects durability, serviceability, longterm reliability, and structural integrity of concrete. Resilient modulus is an important property for asphalt concrete design and for.
Another aim is to find ways to determine the static modulus of elasticity of concrete by nondestructive means primarily ultrasonic pulse method, resonance method and use of electronic rebound hammers, thus to determine the possibility of creating calibration curve for ndt determination of the modulus of elasticity. The ratio between static and dynamic modulus of elasticity in normal and high strength concrete abstract there is a simple linear relationship between the static and dynamic elastic module, this lead to hope that using dynamic elastic modulus may remove the problems in measuring the static elastic modulus of concrete. The modulus of elasticity of concrete is relatively constant at low stress levels but starts decreasing at higher stress levels as matrix cracking develops. While there are many factors for high seismic vulnerability of existing buildings, poor quality of concrete is a major and widespread problem for. The influence of concrete composition on youngs modulus core. Motivation and goal the modulus of elasticity is a fundamental property for concrete and it has become increasingly common for designers to specify a minimum value to be met. The strength of concrete is dependent on the relative proportion and modulus of elasticity of the aggregate. Factors affecting modulus of elasticity as explained earlier, one of the important factors affecting the modulus of elasticity of concrete is the strength of concrete.
Creep is factored in when concrete structures are designed. Pauw, static modulus of elasticity of concrete as affected by density, aci journal proceedings, vol. High strength concrete is characterized by a dense interfacial transition zone itz and behaves differently from low strength concrete. It is found that bodies lose their elastic limit, due to elastic fatigue. Estimation of the static modulus of elasticity of concrete. The modulus of elasticity of concrete is a function of the modulus of elasticity of the aggregates and the cement matrix and their relative proportions. Physically it indicates a materials resistance to being deformed when a. Structural concrete aci31899 and commentary aci 318r99. The concrete technology notes pdf ct notes pdf book starts with the topics covering portland cement, mineral and chemical admixtures, classification of aggregate, factors affecting workability, water cement ratio, compression tests, factors.
Chapter 1 properties of reinforced concrete strength of. Stress, strain and youngs modulus calculator epsilon. A study of factors affecting the flexural tensile strength. Elasticity modulus of concrete with recycled aggregate. Modulus of elasticity of concrete increases approximately with the square root of the strength. The main factors which may affect the values determination of modulus of. Kennedy, discusses factors important in determining the tensile strength of asphalttreated materials and reports findings of an evaluation of eight of these factors. Not only does it demonstrate the ability of concrete to withstand deformation due to applied stress but also its stiffness. This stronger delivered concrete as well the concrete age may give reason for that the modulus of elasticity used in design gives the correct structural deformations. Since concrete is a composite material, consisting of cement paste and aggregate, its modulus of elasticity depends on the moduli of elasticity and the volume fractions of cement paste and aggregate. International codes propose a wide variety of formulae which establish a relationship between modulus of elasticity and compressive strength. Higher strengths give higher value of modulus of elasticity. Factors affecting the tensile properties of concrete. Air travel and train travel are weak substitutes for intercontinental flights but closer substitutes for journeys of around 200400km e.
The elastic modulus was found to be the best indicator for identifying the progression of asr in concrete. Aci 31808, normal weight concrete the modulus of elasticity of concrete is, ec 4700 vfc mpa and. Modulus of elasticity of concrete determination and. Estimation of the static modulus of elasticity of concrete using the impulse excitation technique itc07 atcp br 1 1. The ts500 equation eqn 21 generally overestimates the modulus of elasticity of low strength concrete ispir et al. Previous research on geopolymer material the term geopolymer describing a family of mineral binders those have a polymeric siliconoxygenaluminum framework structure. The strength of concrete is basically referred to compressive strength and it depends upon three factors. To determine the modulus of elasticity of concrete precisely is very important for structures that require strict control of the deformability. Laboratory tests showed the equation to produce good results over a wide range of variables. Elasticity theory of concrete and prediction of static emodulus for.
Loading conditions and moisture content of specimens. Development of the elastic modulus of concrete under different. Most design specifications, such as the american association of state highways and transportation officials aashto bridge specifications, contain a constant value for the moe based on the unit weight of concrete and the concrete. The type of aggregate and the size of the aggregate particles can also influence the tensile strength. Modulus of elasticity dynamic modulus of elasticity poissons ratio creep of concrete factors influencing creep relation between creep and time effects of creep shrinkage types of shrinkage. Mar 04, 2016 compressive strength of concrete is the most important properties of concrete the characteristic strength that is concrete grade is measured by 28day cylindercube strength. Effect of a time dependent concrete modulus of elasticity. Factors affecting youngs modulus the modulus is closely related to the binding energies of the atoms. Modulus of elasticity iof concrete affected by elastic. Binding forces, and thus the modulus of elasticity, are typically higher for high melting point materials. Cement content mix must be designed to ensure cohesion and prevent segregation and bleeding. The experimental evaluation of the modulus of elasticity of conventional concretes and with the re. Modulus of elasticity of concrete concrete technology. Factors governing the strength and elastic properties of a.
Conversely, the evolution of compressive strength was. Some factors affecting the dynamic modulus of elasticity. Modulus of elasticity of concrete civil engineering. This suggests the need to include the type of admixtures as another factor affecting modulus of elasticity. In the theory of reinforced concrete, it is assumed that concrete is elastic, isotropic. There are a few normalised methods of assessing the elastic properties of. The modulus of elasticity youngs modulus e is a material property, that describes its stiffness and is therefore one of the most important properties of solid materials. Concrete is a composite consisting of matrix and aggregates. The number of close substitutes the more close substitutes there are in the market, the more elastic is demand because consumers find it easy to switch. Experimental determination of factors affecting the static. A general equation is derived which expresses the modulus of elasticity of concrete or mortar in terms of an empirical constant the elastic moduli of the cement matrix and aggregate constituents, and the mix proportions. It might vary along the member length and is likely to reach average in its influence on deflection.
Modulus of elasticity of concrete is the ratio of the stress to the strain of the concrete. Pdf modulus of elasticity of low strength concrete. Youngs modulus does depend on orientation of a single crystal material. Procedure overview the determination of the modulus of elasticity for cylindrical concrete samples such as molded cylinders and drilled cores is outlined in this procedure. Chapter 15 modulus of elasticity page 85 tab36 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 lightweight concrete 0,8 2 low alloy steels 200 210 polystyrene 3,2 3,5 silica glass 60 90. The modulus of elasticity of high performance concrete.
Effect of cylinder size on the modulus of elasticity and. Prestress losses assumed for bridge girder design and deflection analyses are dependent on the concrete modulus of elasticity moe. Evaluating the dynamic elastic modulus of concrete using. Concrete compressive strength could be higher as much as 15% than specified and increase modulus of elasticity by 7%.
The effect of the itz properties on the elastic modulus of the cntreinforced cement was investigated using a fourphase axisymmetric model consisting of a single cnt aligned at the center of composite unit. The concrete members, in general, are of large continuous size and have at least minimum reinforcement introducing a confining effect to the concrete. University of canterbury, christchurch, new zealand. Most of these codes are valid up to 50 mpa, the usual limit for normal concretes. Home tools stress, strain and youngs modulus calculator calculators for stress, strain and youngs modulus modulus of elasticity, elastic modulus stress, strain and youngs modulus are all factors linked to the performance of a material in a particular setting. Some factors affecting the dynamic modulus of elasticity of. This can be represented in many ways such as the relationship between ratio of mix or watercement ratio. The different types of shear failure of reinforced concrete rectangular and tbeams are described in order to show that the shear strength depends on factors additional to those recognized by the design formulae. Effect of stress on the dynamic modulus of concrete.
What are properties of hardened concretegoverning factors. Experimental determination of factors affecting the static modulus of elasticity of concrete using nondestructive testing methods. Factors affecting durability of concrete durability of concrete depends upon the following factors. Jan 22, 2017 elastic modulus is a fundamental parameter in designing concrete structures. For isotropic materials, the presence of fractures affects the young and the shear modulus perpendicular to the planes of the cracks, which decrease youngs modulus faster than the shear modulus as the fracture density increases, indicating that the presence of cracks makes bodies brittler. Water tightness impermeability rate of strength gain of concrete. More over, the modulus of elasticity in design is based on concrete 28 day strength, but the concrete, when becomes older, increases its strength and also modulus. Elastic properties of concrete elasticity, creep and shrinkage. Test result of the elastic modulus is usually available for major structures but it is very rare that at least a shortterm creep test is carried. The modulus of elasticity is a property of concrete, which is known for its high variability of. Modulus of elasticity of concrete can be defined as the slope of the line drawn from stress of zero to a compressive stress of 0. Pdf influence of coarse aggregate on concretes elasticity modulus. Strength, modulus of elasticity, creep and shrinkage of concrete.
Concrete technology notes pdf ct notes pdf eduhub sw. Factors affecting elasticity in engineering physics tech. It is one of the most important factors which affect the modulus of elasticity. Following factors affect the value of modulus of elasticity.
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