Age-Adjusted Effective Modulus Method for Creep of High-Performance Concrete

2006 ◽  
Vol 302-303 ◽  
pp. 693-699
Author(s):  
Bing Han ◽  
Yuan Feng Wang
Keyword(s):  
Experimental Data ◽  
Plastic Flow ◽  
High Performance ◽  
High Performance Concrete ◽  
Effective Modulus ◽  
Relaxation Coefficient ◽  
Modulus Method ◽  
Set Up

This paper discusses the suitability of using several creep theories of common concrete for creep of high-performance concrete (HPC). Based on the Age-Adjusted Effective Modulus method (AEMM) for creep of concrete, Improved Dischinger (ID) method and the Elastic Continuation and Plastic Flow (ECPF) theory for calculating relaxation coefficient and considering characteristics of HPC, a method is set up for calculating the creep of HPC under changing stresses, and comparing results gotten by the method with some experimental data, it can be considered that the above methods are suit for the calculation of creep of HPC.

Relaxation of Structural Concrete due to its Shrinkage in Terms of Age-Adjusted Effective Modulus Method

2017 ◽  
Vol 737 ◽  
pp. 471-476
Author(s):  
Lukáš Zvolánek ◽  
Ivailo Terzijski
Keyword(s):  
Residual Stresses ◽  
High Performance ◽  
High Performance Concrete ◽  
Relaxation Mechanism ◽  
Effective Modulus ◽  
Tensile Creep ◽  
Ring Test ◽  
Polypropylene Fibres ◽  
Creep Effect ◽  
Modulus Method

This paper focuses on the calculation of residual stresses due to shrinkage with a tensile creep effect. Whereas the shrinkage of concrete causes stresses in the material, the tensile creep counteracts the shrinkage as a stress relaxation mechanism. The main objective of this paper is to evaluate the ageing coefficient c (referred to as Trost-Bazant Coefficient) reflecting the load history. The coefficient is used for the residual stress analysis by means of a simplified method called Age-adjusted Effective Modulus Method. The tensile creep effect was evaluated according to the rheological model provided by Eurocode 2. Although the Eurocode predicts the creep for the structural members subjected to compressive stresses, this study proves that it can be used for the tensile creep prediction as well. We tested three types of concrete: reference concrete, high-performance concrete with reduced shrinkage magnitude by means of special admixtures, and fibre concrete with the content of polypropylene fibres. From the obtained results, it can be stated, that the ageing coefficient can be considered to be the value of 0.45 for any shrinkage development. It was also proved, that the tensile creep value essentially affects the magnitude of residual stresses, even in the “early age” concrete. The correctness of the calculated residual stresses was verified by means of a Ring-test.

scholarly journals The Compressive Strength of High-Performance Concrete and Ultrahigh-Performance

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
E. H. Kadri ◽  
S. Aggoun ◽  
S. Kenai ◽  
A. Kaci
Keyword(s):  
Experimental Data ◽  
Compressive Strength ◽  
Silica Fume ◽  
High Performance ◽  
High Performance Concrete ◽  
Cementitious Materials ◽  
Strength Gain ◽  
Proposed Model ◽  
Partial Cement Replacement ◽  
Better Than

The compressive strength of silica fume concretes was investigated at low water-cementitious materials ratios with a naphthalene sulphonate superplasticizer. The results show that partial cement replacement up to 20% produce, higher compressive strengths than control concretes, nevertheless the strength gain is less than 15%. In this paper we propose a model to evaluate the compressive strength of silica fume concrete at any time. The model is related to the water-cementitious materials and silica-cement ratios. Taking into account the author's and other researchers’ experimental data, the accuracy of the proposed model is better than 5%.

Permeability Measurement of High Performance Concrete at Elevated Temperature Employing a New Test Set-Up

2015 ◽  
Vol 1124 ◽  
pp. 288-293
Author(s):  
Michaela Fiedlerová ◽  
Johannes Kirnbauer ◽  
Heinrich Bruckner
Keyword(s):  
Elevated Temperature ◽  
High Performance ◽  
Building Materials ◽  
High Performance Concrete ◽  
Gas Permeability ◽  
Permeability Measurement ◽  
Test Set ◽  
Testing Procedures ◽  
Heating And Cooling ◽  
Set Up

This paper is focused on clarifying behaviour of concrete at elevated temperature with employing new test set-up constructed at Institute of Building Construction and Technology, Vienna University of Technology. This unique test set-up allows measuring gas permeability of different building materials such as concrete or ceramic at both high temperature (up to 400°C) and pressure (up to 6 bars). Present paper illustrates a new set up for permeability measurement during the heating and cooling and different testing procedures and evaluation of their influence on results.

scholarly journals Experimental investigation on radiation shielding of high performance concrete for nuclear and radiotherapy facilities

2016 ◽  
Vol 22 (2) ◽  
pp. 41-47 ◽  
Author(s):  
Szymon Domański ◽  
Michał A. Gryziński ◽  
Maciej Maciak ◽  
Łukasz Murawski ◽  
Piotr Tulik ◽  
...  
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Absorbed Dose ◽  
Nuclear Research ◽  
Neutron Radiation ◽  
Radiation Shielding ◽  
Transmitted Radiation ◽  
Radiation Fields ◽  
Shielding Properties ◽  
Set Up

Abstract This paper presents the set of procedures developed in Radiation Protection Measurements Laboratory at National Centre for Nuclear Research for evaluation of shielding properties of high performance concrete. The purpose of such procedure is to characterize the material behaviour against gamma and neutron radiation. The range of the densities of the concrete specimens was from 2300 to 3900 kg/m3. The shielding properties against photons were evaluated using 137Cs and 60Co sources. The neutron radiation measurements have been performed by measuring the transmitted radiation from 239PuBe source. Scattered neutron radiation has been evaluated using the shadow cone technique. A set up of ionization chambers was used during all experiments. The gamma dose was measured using C-CO2 ionization chamber. The neutron dose was evaluated with recombination chamber of REM-2 type with appropriate recombination method applied. The method to distinguish gamma and neutron absorbed dose components in mixed radiation fields using twin detector method was presented. Also, recombination microdosimetric method was applied for the obtained results. Procedures to establish consecutive half value layers and tenth value layers (HVL and TVL) for gamma and neutron radiation were presented. Measured HVL and TVL values were linked with concrete density to highlight well known dependence. Also, influence of specific admixtures to concrete on neutron attenuation properties was studied. The results confirmed the feasibility of approach for the radiation shielding investigations.

scholarly journals Predicting Ultra-High-Performance Concrete Compressive Strength Using Tabular Generative Adversarial Networks

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4757
Author(s):  
Afshin Marani ◽  
Armin Jamali ◽  
Moncef L. Nehdi
Keyword(s):  
Machine Learning ◽  
Experimental Data ◽  
Compressive Strength ◽  
High Performance ◽  
High Performance Concrete ◽  
Synthetic Data ◽  
Generative Adversarial Networks ◽  
Ultra High Performance Concrete ◽  
Adversarial Networks ◽  
Insight Into

There have been abundant experimental studies exploring ultra-high-performance concrete (UHPC) in recent years. However, the relationships between the engineering properties of UHPC and its mixture composition are highly nonlinear and difficult to delineate using traditional statistical methods. There is a need for robust and advanced methods that can streamline the diverse pertinent experimental data available to create predictive tools with superior accuracy and provide insight into its nonlinear materials science aspects. Machine learning is a powerful tool that can unravel underlying patterns in complex data. Accordingly, this study endeavors to employ state-of-the-art machine learning techniques to predict the compressive strength of UHPC using a comprehensive experimental database retrieved from the open literature consisting of 810 test observations and 15 input features. A novel approach based on tabular generative adversarial networks was used to generate 6513 plausible synthetic data for training robust machine learning models, including random forest, extra trees, and gradient boosting regression. While the models were trained using the synthetic data, their ability to generalize their predictions was tested on the 810 experimental data thus far unknown and never presented to the models. The results indicate that the developed models achieved outstanding predictive performance. Parametric studies using the models were able to provide insight into the strength development mechanisms of UHPC and the significance of the various influential parameters.

Estimating Strength of Concrete Using a Genetic Algorithm Combining Operation Tree (GAOT)

2013 ◽  
Vol 325-326 ◽  
pp. 1293-1296 ◽  
Author(s):  
Kuan Ting Chen ◽  
Li Chen ◽  
You Rong Fu ◽  
Sing Han Chen
Keyword(s):  
Experimental Data ◽  
Genetic Algorithm ◽  
Compressive Strength ◽  
High Performance ◽  
Model Building ◽  
High Performance Concrete ◽  
Highly Nonlinear ◽  
Mathematical Equations ◽  
Novel Model ◽  
Building Technique

The main purpose of this paper is to propose an incorporating a genetic algorithm (GA) into the Operation Tree (OT), called GAOT, and apply it to estimate the compressive strength of high-performance concrete (HPC). A large number of experimental data were used to compare accuracies of the model building technique. The results show that this novel model, GAOT, can obtain highly nonlinear mathematical equations with low estimating errors for predicting the compressive strength of HPC.

scholarly journals Influence of Boundary Conditions on Numerical Homogenization of High Performance Concrete

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1009
Author(s):  
Arkadiusz Denisiewicz ◽  
Mieczysław Kuczma ◽  
Krzysztof Kula ◽  
Tomasz Socha
Keyword(s):  
Experimental Data ◽  
Finite Element Method ◽  
Finite Element ◽  
Boundary Conditions ◽  
Representative Volume Element ◽  
High Performance ◽  
High Performance Concrete ◽  
Volume Element ◽  
Numerical Homogenization ◽  
Representative Volume

Concrete is the most widely used construction material nowadays. We are concerned with the computational modelling and laboratory testing of high-performance concrete (HPC). The idea of HPC is to enhance the functionality and sustainability of normal concrete, especially by its greater ductility as well as higher compressive, tensile, and flexural strengths. In this paper, the influence of three types (linear displacement, uniform traction, and periodic) of boundary conditions used in numerical homogenization on the calculated values of HPC properties is determined and compared with experimental data. We take into account the softening behavior of HPC due to the development of damage (micro-cracks), which finally leads to failure. The results of numerical simulations of the HPC samples were obtained by using the Abaqus package that we supplemented with our in-house finite element method (FEM) computer programs written in Python and the homogenization toolbox Homtools. This has allowed us to better account for the nonlinear response of concrete. In studying the microstructure of HPC, we considered a two-dimensional representative volume element using the finite element method. Because of the random character of the arrangement of concrete’s components, we utilized a stochastic method to generate the representative volume element (RVE) structure. Different constitutive models were used for the components of HPC: quartz sand—linear elastic, steel fibers—ideal elastic-plastic, and cement matrix—concrete damage plasticity. The numerical results obtained are compared with our own experimental data and those from the literature, and a good agreement can be observed.

scholarly journals Experimental comparative investigation on creep behavior of mineral cast, ultra-high-performance concrete, and natural stone for precision machinery structures

2021 ◽  
Author(s):  
Eduard Relea ◽  
Benjamin Pfyffer ◽  
Lukas Weiss ◽  
Konrad Wegener
Keyword(s):  
Machine Tool ◽  
Creep Behavior ◽  
High Performance ◽  
High Performance Concrete ◽  
Comparative Investigation ◽  
Natural Stone ◽  
Ultra High Performance Concrete ◽  
Welded Steel ◽  
Iron Mineral ◽  
Set Up

AbstractPrecision machinery employs a variety of materials for its structures: welded steel, cast iron, mineral cast, ultra-high-performance concrete, and natural stone. The machine tool industry requires high control on the geometrical and dimensional stability of the machine structure in order to ensure precise and accurate parts in the micrometer range. This means that even the smallest deviation from the nominal values of the machine tool can result in unacceptable part tolerances. For this work, comparative experiments were set up to analyze and evaluate the influence of load on the creep behavior of three classes of materials: mineral cast, ultra-high-performance concrete, and natural stone.

scholarly journals PREDICTION OF STRENGTH AND SLUMP OF RICE HUSK ASH INCORPORATED HIGH-PERFORMANCE CONCRETE

2012 ◽  
Vol 18 (3) ◽  
pp. 310-317 ◽  
Author(s):  
Md. Nazrul Islam ◽  
Muhammad Fauzi Mohd Zain ◽  
Maslina Jamil
Keyword(s):  
Experimental Data ◽  
Compressive Strength ◽  
Rice Husk ◽  
High Performance ◽  
Rice Husk Ash ◽  
High Performance Concrete ◽  
Fine Aggregate ◽  
Aggregate Content ◽  
Binder Ratio ◽  
Water To Binder Ratio

This paper describes the development of statistical models to predict strength and slump of rice husk ash (RHA) incorporated high-performance concrete (HPC). Sixty samples of RHA incorporated HPC mixes having compressive strength range of 42–92 MPa and slump range of 170–245 mm were prepared and tested in the laboratory. These experimental data of sixty RHA incorporated HPC mixes were used to develop two models. Six variables namely water-to-binder ratio, cement content, RHA content, fine aggregate content, coarse aggregate content and superplasticizer content were selected to develop the models and ultimately to predict strength and slump of RHA incorporated HPC. The models were developed by regression analysis. Additional five HPC mixes were prepared with the same ingredients and tested under the same testing conditions to verify the ability of the proposed models to predict the responses. The results of the prediction of the models showed good agreement with the experimental data. Thus the developed models can be used to predict slump and 28-day compressive strength of RHA incorporated HPC. The research demonstrated that strength and slump of HPC could be successfully modeled using statistical analysis.

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