Estimation of the Modulus of Elasticity for Dam Concrete (original) (raw)
Related papers
Prediction of the Modulus of Elasticity of High Strength Concrete
The prediction of the mechanical characteristics of concrete according to its components' properties has been of great interest. In the current study, attempts have been made to extract some experimental models to predict the modulus of elasticity of high strength concrete based on some known characteristics of the concrete mix. To do so, 45 mix proportions including 5 different ratios of silica fume, i.e., SF/CM = 0, 5, 10, 15 and 20 percent, 3 water to cementitious materials ratios, i.e., W/CM = 0.24, 0.3 and 0.4, and 3 types of coarse aggregates, i.e., limestone, quartzite and andesite were selected. 540 cylindrical specimens were cast, cured and tested after 7, 28 and 91 days. Regarding different ratios of silica fume and different ratios of W/CM, the relationship of modulus of elasticity of coarse aggregate and concrete at different ages was discussed and some empirical equations were proposed. Special emphasis was paid on two proposed models, the comprehensive model and th...
A Practical Equation for Elastic Modulus of Concrete
ACI Structural Journal
Many empirical equations for predicting the modulus of elasticity as a function of compressive strength can be found in the current literature. They are obtained from experiments performed on a restricted number of concrete specimens subjected to uniaxial compression. Thus, the existing equations cannot cover the entire experimental data. This is due to the fact that mechanical properties of concrete are highly dependent on the types and proportions of binders and aggregates. To introduce a new reliable formula, more than 3000 data sets, obtained by many investigators using various materials, have been collected and analyzed statistically. The compressive strengths of the considered concretes range from 40 to 160 MPa (5.8 to 23.2 ksi). As a result, a practical and universal equation, which also takes into consideration the types of coarse aggregates and mineral admixtures, is proposed.
5th World Congress on Civil, Structural, and Environmental Engineering (CSEE'20) Lisbon, Portugal – April, 2020, 2020
The modulus of elasticity is a most fundamental parameter widely applied in most fields of science and engineering. In the design of plain, reinforced, and prestressed concrete structures, the elastic modulus, is most useful. For example, linear analysis of elements based on the theory of elasticity may be adopted to satisfy both the requirements of ultimate and serviceability limit states. This is factual, for instance, in the case of prestressed concrete structures, which show uncracked cross sections up to failure. Similarly, an appropriately precise value of also enables estimation of stresses and deflections which should be limited within the permissible range of serviceability of concrete structures. Given its vitality therefore, various empirical models for predicting the modulus of elasticity as a function of compressive strength, ′ are reported in literature, manuals and guidelines. These model equations, typified by varying α-coefficients and β-exponents for ′ and δ-exponents for concrete density (), are predominantly derived from experimental testing performed on a restricted number of concrete specimens subjected to uniaxial compression. As a consequence, their range of application is limited to normal strength concrete (NSC), deviating significantly when adopted for determining for aerated, lightweight, lean and high strength concretes. In an attempt to correct this, various standards and institutions have proposed separate models for high strength concrete (HSC), which are still based on limited data and do not take into account the effects of the types and proportions of binders and aggregates. In this Study, unique universal models developed on the basis of a large amount of data, types of concrete and wide ranges of compressive strengths; [ ′ ≤ 9 and ′ ≥ 9 ~ 160 ] from literature, are proposed. Furthermore, models for determining the appropriate flexural strength and Poisson's ratio incorporating density effects are also proposed and validated accordingly.
Title no. 106-S64 A Practical Equation for Elastic Modulus of Concrete
Many empirical equations for predicting the modulus of elasticity as a function of compressive strength can be found in the current literature. They are obtained from experiments performed on a restricted number of concrete specimens subjected to uniaxial compression. Thus, the existing equations cannot cover the entire experimental data. This is due to the fact that mechanical properties of concrete are highly dependent on the types and proportions of binders and aggregates. To introduce a new reliable formula, more than 3000 data sets, obtained by many investigators using various materials, have been collected and analyzed statistically. The compressive strengths of the considered concretes range from 40 to 160 MPa (5.8 to 23.2 ksi). As a result, a practical and universal equation, which also takes into consideration the types of coarse aggregates and mineral admixtures, is proposed.
Matéria (Rio de Janeiro), 2021
The modulus of elasticity of concrete is often calculated as a function of the compressive strength, and as a deterministic value. However, variations in the aggregates properties may result in module values different than those estimated, which may lead to excessive deformation and eventual instability of the structure. In this work, the influence of the coarse aggregate batch variation on the variability of the modulus of elasticity of the concrete was investigated. Three different aggregate sources (one of granite origin and two of gneiss origin), three water/cement ratios (w/c) and five different batches of each aggregate were investigated. The compressive strength and static modulus of elasticity of the concretes were determined at 28 days. The analysis of variance (ANOVA) showed that the variable "batch" had a significant influence on the modulus of elasticity of the concrete, indicating that this property is a probabilistic variable indeed. The normality of the distribution of its values was attested, and values of characteristic modulus of elasticity were proposed, which were from 6 to 10% lower than the mean values. In addition, the use of gneissic aggregates led to modulus of elasticity values 30% higher than those of the concretes with granitic aggregates and equivalent compressive strengths, while the reduction of the w/c ratio from 0.71 to 0.46 increased the modulus of elasticity in about 5%.
Estimation of ultimate modulus of elasticity and Poisson ratio of normal concrete
Cement and Concrete Composites, 2004
The relationship between compressive strength of concrete and modulus of elasticity, and between compressive strength of concrete and Poisson ratio was investigated in this study by using the cement hydration equation. The hydration criteria of modulus of elasticity and Poisson ratio of concrete are established hydration criteria and for this reason the cement hydration equation can be used for calculating their accurate values up to the final hydration. Because of the applicability of cement hydration equation to the hydration criteria of modulus of elasticity, Poisson ratio and compressive strength of mortar and concrete, there is a linear relationship between any two of them according to the results of previous study. If examined mortar and concrete were prepared using the same cement. Hence, the ''method of two points proportionality'' can be used to estimate ultimate modulus of elasticity and Poisson ratio using only two measured values of these properties at ages 6 28 days (e.g. at 7 and 28 days) and the hydration criterion of mortar's compressive strength.
Modulus of elasticity of low strength concrete
In Turkey, many existing reinforced concrete buildings are in urgent need of seismic retrofitting. While there are many factors for high seismic vulnerability of existing buildings, poor quality of concrete is a major and widespread problem for existing buildings all around Turkey. In recent years, after revision of the seismic design code and inclusion of a seismic assessment and retrofitting part in the revised code, the number of seismic retrofitting applications has increased significantly. While carrying out a structural analysis for existing buildings, the assumption on the modulus of elasticity of concrete is vitally important. It is known that the code equations are established based on experimental results obtained for normal strength concretes and may not be valid for low strength concrete. Therefore, in this study, a preliminary work is carried out for determining the modulus of elasticity of low strength concrete. The experimental data of this work is compiled from the c...
Proceedings of the Institution of Civil Engineers - Structures and Buildings, 2019
The estimation of the elastic modulus of concrete is important in structural design. The characteristics of aggregate, especially its stiffness, have a profound influence on the elastic modulus of the concrete. However, this parameter is found not to be properly considered in the elastic modulus models used in current design codes, or in those developed by established organisations and individual researchers. In this study, the importance of stiffness and water absorption of natural aggregate and recycled and secondary aggregates are discussed. The parameters used in the existing elastic models are presented and three models, namely, ACI 209.2R-08, Eurocode 2 and B4, are assessed for their accuracy in estimating the elastic modulus of concrete made with both natural aggregate and recycled and secondary aggregates. A new empirical model essentially based on aggregate stiffness in the form of aggregate absorption, aggregate content and its ratio to cement content, has been developed f...
Influences of Concrete Elasticity Modulus and Long -Term Observation of Structures
The paper will propose a very simple procedure for the calculation of stresses and strains during long-term observation of concrete structures, when a procedure has already been formed in which E (t) = E 0 .The application the modulus of elasticity of concrete is, until now, a problem, that it seems, has not been sufficiently solved in the practice and theory of RC, PC and Composite structures. A new stress-strain relation is presented, which simply complements previously published relations, which have been successfully applied in the design and construction of structures for over 60 years. An answer will be given when the creep measure (specific viscous strain) may be erroneous or insufficiently accurate through the examples of several well-known authors.The paper contains the second part of the material published in this journal (see:[17]).
This work proposes a methodology to predict the elastic modulus of lightweight aggregate concretes. To this end an analytical formula is achieved by curve fitting experimental results from 135 concrete samples made of 45 different mixes. The validation of the proposed methodology is carried out by applying the obtained analytical formula to a set of 90 concrete samples made of 30 different mixes. Comparisons with other methods applied to predicting the elastic modulus of lightweight aggregate concretes indicate that the results show good agreement and suggest that the proposed methodology could be applied in practical situations.