Drying Shrinkage of Concrete: Experiments and Numerical Models

2017 ◽  
Vol 259 ◽  
pp. 46-51 ◽  
Author(s):  
Marek Vinkler ◽  
Jan L. Vítek
Keyword(s):  
Relative Humidity ◽  
Numerical Models ◽  
Drying Shrinkage ◽  
Shrinkage Strain ◽  
Experimental Program ◽  
Model Code ◽  
Wire Strain ◽  
Model Code 2010 ◽  
Different Depths ◽  
Pore Relative Humidity

The paper presents some results of experimental program focused on drying and shrinkage of large concrete specimens. Segments of walls with thicknesses 200, 400 and 800 mm and standard cylinders 150x300 mm were used as specimens. Each segment has embedded 4 vibrating wire strain gauges in axis plane for measurements of shrinkage strain and plastic tubes of various lengths for measurements of pore relative humidity in different depths. Relative humidity and temperature of ambient environment were not controlled, however they were recorded very closely. Measure shrinkage strains are compared with prediction based on shrinkage models. The most important predictive models are used for comparison: Model Code 2010, Eurokód 2, Model ACI 209-R92, Model B4 a Model B4s.

scholarly journals The role of ambient temperature variation on drying shrinkage development of self-compacting Portland-limestone cement concrete

2018 ◽  
Vol 162 ◽  
pp. 02021
Author(s):  
Basil Al-Shathr ◽  
Ammar Abdulameer ◽  
Tareq al-Attar
Keyword(s):  
Relative Humidity ◽  
Ambient Temperature ◽  
Temperature Variation ◽  
Drying Shrinkage ◽  
Shrinkage Strain ◽  
Type I ◽  
Portland Limestone Cement ◽  
Accumulated Strain ◽  
Limestone Cement ◽  
Temperature Records

The ambient temperature records in Iraq show a large variation between day and night reaching 20 C, depending on the season, whether it is summer or winter. For this reason, the aim of this research is to study the effect of these conditions on the drying shrinkage of self-compacting concrete produced by using Portland-Limestone cement (ASTM C595 - Type IL). SCC mixes were designed to attain compressive strengths of 40 and 60MPa at 28days with and without silica fume respectively. Same mixes were reproduced with ordinary Portland cement (ASTM C150 - Type I) for comparisons. Two maximum sizes of aggregate 10 and 20 mm were incorporated in this work. The drying shrinkage was measured for 180 days after 7 days of water curing. The range of ambient (outdoor) temperature variation was from - 4 to + 39°C and the relative humidity ranged from 15 to 60 %. The results of this exposure were compared to that of specimens kept in the shrinkage chamber, with a temperature of 21°C and relative humidity 35%. The current results showed that due to the irreversible nature of shrinkage strain, the drop of ambient temperature and the rise of atmosphere moisture or relative humidity would not reverse the shrinkage strain. It is important to figure the final total accumulated strain when dealing with ambient temperature variation. The drying shrinkage characteristics for concrete made with Type IL cement, are found similar to that for concrete produced with Type I cement.

scholarly journals COMPARISON OF DRYING SHRINKAGE AND DRYING CREEP KINETICS IN CONCRETE

2018 ◽  
Vol 15 ◽  
pp. 12-19
Author(s):  
Lenka Dohnalová ◽  
Petr Havlásek
Keyword(s):  
Prediction Models ◽  
Drying Shrinkage ◽  
Material Model ◽  
Material Point ◽  
Point Of View ◽  
Model Code ◽  
Model Code 2010 ◽  
Basic Equations ◽  
Drying Creep ◽  
Long Term Behavior

The aim of this paper is to show and compare the time evolution of drying shrinkage and drying creep in concrete from three different perspectives. The first one analyzes the basic equations defined in the most common design codes and prediction models for the description of the long-term behavior of concrete (ACI 209, EC2, Model Code 2010, B3, B4). Next, the evolution of drying creep and shrinkage is examined by processing suitable experimental data available from the database developed at the Northwestern University. Finally, the last point of view investigates the results obtained from the finite element simulations employing the material point approach, in particular, the material model based on the Microprestress-Solidification theory.

scholarly journals Comparison of Drying Shrinkage of Concrete Specimens Recycled Heavyweight Waste Glass and Steel Slag as Aggregate

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5084
Author(s):  
So Yeong Choi ◽  
Il Sun Kim ◽  
Eun Ik Yang
Keyword(s):  
Prediction Models ◽  
Steel Slag ◽  
Drying Shrinkage ◽  
Shrinkage Strain ◽  
Waste Glass ◽  
Fine Aggregate ◽  
Model Code ◽  
Fundamental Properties ◽  
Substitution Ratio ◽  
Experimental Values

This study analyzed the fundamental properties of concrete using steel slag, to test its viability as an aggregate material. An experimental investigation into the effect of steel slag as a coarse aggregate, and heavyweight waste glass as a fine aggregate, on the drying shrinkage of concrete was performed. The calculated shrinkage strain was compared to five different shrinkage prediction models, namely, the ACI 209, B3, KCI 2012, EC 2 and GL 2000 model codes, to evaluate their ability to accurately predict shrinkage behavior. From the results, the elastic modulus of concrete increased with the increase in steel slag substitution ratio, however drying shrinkage decreased. The predictive value of the existing prediction model of drying shrinkage differed from the experimental values, and requires correction to improve its accuracy. The B3 model code showed the best prediction results of drying shrinkage.

Analysis of the concrete shrinkage effects on the real behavior of the spatial concrete and reinforced concrete structures using the thermal analogy

2019 ◽  
Vol 37 (4) ◽  
pp. 1451-1472
Author(s):  
Ante Džolan ◽  
Mladen Kožul ◽  
Alen Harapin ◽  
Dragan Ćubela
Keyword(s):  
Numerical Model ◽  
Prestressed Concrete ◽  
Three Dimensional ◽  
Concrete Structures ◽  
Shrinkage Strain ◽  
Content Type ◽  
Model Code ◽  
Concrete Shrinkage ◽  
Model Code 2010 ◽  
Real Behavior

Purpose This paper aims to present an approach for the numerical simulation of concrete shrinkage. First, some physical mechanisms of shrinkage are described and then the developed numerical model for the analysis of shrinkage of spatial three-dimensional structures using thermal analogy is presented. Results of the real behavior of structures because of concrete shrinkage using the developed numerical model are compared with the experimental and it is clearly shown that the developed numerical model is an efficient tool in predicting the time-dependent behavior of all concrete structures. Design/methodology/approach In this paper, Fib Model Code 2010 to predict shrinkage deformation of concrete is used, and it was incorporated in the three-dimensional numerical model using the thermal analogy. Mentioned three-dimensional numerical model uses the modified Rankine material law to describe concrete behavior in tension and modified Mohr-Coulomb material law to describe concrete behavior in compression. The developed three-dimensional numerical model successfully analyzes the behavior of reinforced and/or prestressed concrete structures including time-dependent deformations of concrete as well. Findings Results are shown in this paper clearly demonstrate the reliability of the developed numerical model in predicting the shrinkage strain, as well as its impact on concrete and reinforced concrete structures. The results obtained using the developed numerical model are in better agreement with the experimental results, than the results obtained using the numerical models from literature that also use the Fib Model Code 2010 to predict the shrinkage strain. So, it can be concluded that for a real simulation of concrete structures, alongside the model for predicting the shrinkage strain, the models for concrete behavior in tension and compression have a very important role. Originality/value Results of the developed three-dimensional numerical model were compared with experimental results from literature and with theoretical foundations, and it can be talked that this numerical model presents a good tool for analysis of reinforced and prestressed concrete structures including shrinkage deformation of concrete. Results obtained using the developed three-dimensional numerical model are better agreed with experimental than results of other numerical model from literature.

fib Bulletin 65. Model code 2010 Volume 1

2012 ◽  
Author(s):  
Walraven ◽  
Bigaj-van Vliet ◽  
Balazs ◽  
Cairns ◽  
Cervenka ◽  
...  
Keyword(s):  
Model Code ◽  
Model Code 2010

scholarly journals Long-Term Concrete Shrinkage Influence on the Performance of Reinforced Concrete Structures

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 254
Author(s):  
Alinda Dey ◽  
Akshay Vijay Vastrad ◽  
Mattia Francesco Bado ◽  
Aleksandr Sokolov ◽  
Gintaris Kaklauskas
Keyword(s):  
Reinforced Concrete ◽  
Reinforced Concrete Structures ◽  
Tension Stiffening ◽  
Model Code ◽  
Concrete Shrinkage ◽  
Time Period ◽  
Governing Factor ◽  
Model Code 2010 ◽  
Mathematical Process

The contribution of concrete to the tensile stiffness (tension stiffening) of a reinforced concrete (RC) member is a key governing factor for structural serviceability analyses. However, among the current tension stiffening models, few consider the effect brought forth by concrete shrinkage, and none studies take account of the effect for very long-term shrinkage. The present work intends to tackle this exact issue by testing multiple RC tensile elements (with different bar diameters and reinforcement ratios) after a five-year shrinking time period. The experimental deformative and tension stiffening responses were subjected to a mathematical process of shrinkage removal aimed at assessing its effect on the former. The results showed shrinkage distinctly lowered the cracking load of the RC members and caused an apparent tension stiffening reduction. Furthermore, both of these effects were exacerbated in the members with higher reinforcement ratios. The experimental and shrinkage-free behaviors of the RC elements were finally compared to the values predicted by the CEB-fib Model Code 2010 and the Euro Code 2. Interestingly, as a consequence of the long-term shrinkage, the codes expressed a smaller relative error when compared to the shrinkage-free curves versus the experimental ones.

scholarly journals Punching strength of reinforced concrete flat slabs without shear reinforcement

2012 ◽  
Vol 5 (5) ◽  
pp. 659-691 ◽  
Author(s):  
P. V. P. Sacramento ◽  
M. P. Ferreira ◽  
D. R. C. Oliveira ◽  
G. S. S. A. Melo
Keyword(s):  
Reinforced Concrete ◽  
Shear Crack ◽  
Theoretical Method ◽  
Shear Reinforcement ◽  
Model Code ◽  
Flat Slabs ◽  
Codes Of Practice ◽  
Eurocode 2 ◽  
Model Code 2010 ◽  
Theoretical Results

Punching strength is a critical point in the design of flat slabs and due to the lack of a theoretical method capable of explaining this phenomenon, empirical formulations presented by codes of practice are still the most used method to check the bearing capacity of slab-column connections. This paper discusses relevant aspects of the development of flat slabs, the factors that influence the punching resistance of slabs without shear reinforcement and makes comparisons between the experimental results organized in a database with 74 slabs carefully selected with theoretical results using the recommendations of ACI 318, EUROCODE 2 and NBR 6118 and also through the Critical Shear Crack Theory, presented by Muttoni (2008) and incorporated the new fib Model Code (2010).

Automated structural assessment of existing reinforced concrete underpasses

2021 ◽  
Author(s):  
Danny Jilissen ◽  
Rob Vergoossen ◽  
Yuguang Yang ◽  
Eva Lantsoght
Keyword(s):  
Reinforced Concrete ◽  
The Netherlands ◽  
Analytical Model ◽  
Load Distribution ◽  
Traffic Load ◽  
Sensitivity Analyses ◽  
Fem Model ◽  
Structural Assessment ◽  
Model Code ◽  
Model Code 2010

<p>Due to the large number of underpasses in the Netherlands that have to be assessed, a project at the Delft University of Technology in cooperation with Royal HaskoningDHV was started. Research was conducted into the automation of the structural assessment of existing reinforced concrete underpasses in the Netherlands. The developed Automated Structural Assessment Tool (ASA Tool) consists of an analytical model and a 2.5D FEM model. The analytical model uses traffic load distribution following the Guyon-Massonnet-Bares method for bending and a method based on <i>fib </i>Model Code 2010 for shear. The script-based 2.5D FEM model uses 2D shell elements and performs a linear elastic analysis. The input and output can be linked to a database for assessment of large batches. Sensitivity analyses showed that in-plane load distribution following <i>fib </i>Model Code 2010 combined with vertical load distribution according to EN 1991-2:2003 results in underestimated shear forces.</p>

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