Estimating on Creep Strain for Ready-Mixed Concrete during Shrinkage

2013 ◽  
Vol 357-360 ◽  
pp. 684-688
Author(s):  
Liang Li Xiao ◽  
Ming Yang Pan ◽  
Meng Chen
Keyword(s):  
Experimental Data ◽  
Reinforced Concrete ◽  
Creep Strain ◽  
Equilibrium Condition ◽  
Concrete Structures ◽  
Plain Concrete ◽  
Shrinkage Strain ◽  
Important Data ◽  
Experimental Part ◽  
Ready Mixed Concrete

This paper presents the development of formulas to estimate the creep strain of the reinforced concrete specimens. The experimental part of the work focused on the dispersion of shrinkage strain between reinforced concrete and plain concrete specimens, as well as the equilibrium condition between concrete tension and reinforcement compression. Based upon the experimental data and development formula, the creep strain and concrete age curves of the reinforced concrete specimens are drawn. Moreover, the characteristics of the creep strain are analyzed in detail. The creep strain formula can provide the important data and theoretic basis to “the code for design of concrete structures”（GB50010－2010）.

scholarly journals FLEXURAL IMPROVEMENT OF PLAIN CONCRETE BEAMS STRENGTHENED WITH HIGH PERFORMANCE FIBRE REINFORCED CONCRETE

2017 ◽  
Vol 36 (3) ◽  
pp. 697-704
Author(s):  
MN Isa
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
Concrete Beams ◽  
Concrete Structures ◽  
High Strength ◽  
Plain Concrete ◽  
Analytical Investigation ◽  
Fibre Reinforced Concrete ◽  
Load Bearing Capacity ◽  
High Performance Fibre

Strengthening of concrete structures have become inevitable due to unavoidable factors such as fatigue and aggressive environmental conditions causing deterioration of concrete structures. Many researchers have turned in the direction of using various high strength and high performance concretes due to their high structural and durability properties, for the purpose of repair and strengthening of concrete structures against these aggressive conditions. As a result, this study carryout experimental, numerical and analytical investigation to study the behaviour of plain concrete (PC) beams strengthened with High Performance Fibre Reinforced Concrete (HPFRC) layer using three different jacketing configurations and tested in flexure. Results show significant improvement in both stiffness and load bearing capacity of plain concrete beams. http://dx.doi.org/10.4314/njt.v36i3.6

scholarly journals Empirical model of corrosion rate for steel reinforced concrete structures in chloride-laden environments

2018 ◽  
Vol 22 (1) ◽  
pp. 223-239 ◽  
Author(s):  
Zhao-Hui Lu ◽  
Pei-Yuan Lun ◽  
Wengui Li ◽  
Zhiyu Luo ◽  
Yuelin Li ◽  
...  
Keyword(s):  
Experimental Data ◽  
Reinforced Concrete ◽  
Corrosion Rate ◽  
Empirical Model ◽  
Concrete Structures ◽  
Empirical Models ◽  
Reinforced Concrete Structures ◽  
Reinforcing Steel ◽  
Model Errors ◽  
Efficient Prediction

The corrosion rate of reinforcing steel is an important factor to determine the corrosion propagation of reinforced concrete structures in the chloride-laden environments. Since the corrosion rate of reinforcing steel is affected by several coupled parameters, the efficient prediction of which remains challenging. In this study, a total of 156 experimental data on corrosion rate from the literature were collected and compared. Seven empirical models for predicting the corrosion rate were reviewed and investigated using the collected experimental data. Based on the investigations, a new empirical model is proposed for predicting the corrosion rate in corrosion-affected reinforced concrete structures considering parameters including concrete resistivity, temperature, relative humidity, corrosion duration and concrete chloride content. The comparison between the experimental data and those predicted using the new empirical model demonstrates that the new model gives a good prediction of the corrosion rate. Furthermore, the uncertainty and probability characteristics of these empirical models are also investigated. It is found that the probability distributions of the model errors can be described as lognormal, normal, Weibull or Gumbel distributions. As a result, the new empirical model can provide an efficient prediction of the corrosion rate of reinforcing steel, and the model error analysis results can be utilized for reliability-based service life prediction of reinforced concrete structures under chloride-laden environments.

Polymer-Cement Material for Corrosion Protection of Reinforced Concrete Elements

2016 ◽  
Vol 871 ◽  
pp. 104-109 ◽  
Author(s):  
Yuri B. Potapov ◽  
Sergey A. Pinaev ◽  
Arutyun A. Arakelyan ◽  
Andrei D. Barabash
Keyword(s):  
Experimental Data ◽  
Reinforced Concrete ◽  
Corrosion Protection ◽  
Concrete Structures ◽  
Protective Layer ◽  
Reinforced Concrete Structures ◽  
Corrosive Media ◽  
Cement Material ◽  
Innovative Material ◽  
Concrete Elements

The paper presents composition of innovative material used for corrosion protection of reinforced concrete structures and experimental data on the increase in cracking of reinforced concrete elements coated with polymer-cement protective layer against corrosive media.

Design of precast reinforced concrete structures of frame buildings: a new set of rules

2019 ◽  
pp. 4-9 ◽  
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Building Frames ◽  
Fine Grained ◽  
Rigid Frame ◽  
Floor Slabs ◽  
Frame Buildings ◽  
Spatial System ◽  
Precast Elements

Currently, prefabricated reinforced concrete structures are widely used for the construction of buildings of various functional purposes. In this regard, has been developed SP 356.1325800.2017 "Frame Reinforced Concrete Prefabricated Structures of Multi-Storey Buildings. Design Rules", which establishes requirements for the calculation and design of precast reinforced concrete structures of frame buildings of heavy, fine-grained and lightweight structural concrete for buildings with a height of not more than 75 m. The structure of the set of rules consists of eight sections and one annex. The document reviewed covers the design of multi-story framed beam structural systems, the elements of which are connected in a spatial system with rigid (partially compliant) or hinged joints and concreting of the joints between the surfaces of the abutting precast elements. The classification of structural schemes of building frames, which according to the method of accommodation of horizontal loads are divided into bracing, rigid frame bracing and framework, is presented. The list of structural elements, such as foundations, columns, crossbars, ribbed and hollow floor slabs and coatings, stiffness elements and external enclosing structures is given; detailed instructions for their design are provided. The scope of the developed set of rules includes all natural and climatic zones of the Russian Federation, except seismic areas with 7 or more points, as well as permafrost zones.

Improvement Of Curvilinear Diagrams Of Concrete Deformation

2019 ◽  
pp. 99-104
Keyword(s):  
Reinforced Concrete ◽  
Peak Load ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Deformation Model ◽  
Reinforced Concrete Structures ◽  
Significant Difference ◽  
Deformation Diagrams

Problems when calculating reinforced concrete structures based on the concrete deformation under compression diagram, which is presented both in Russian and foreign regulatory documents on the design of concrete and reinforced concrete structures are considered. The correctness of their compliance for all classes of concrete remains very approximate, especially a significant difference occurs when using Euronorm due to the different shape and sizes of the samples. At present, there are no methodical recommendations for determining the ultimate relative deformations of concrete under axial compression and the construction of curvilinear deformation diagrams, which leads to limited experimental data and, as a result, does not make it possible to enter more detailed ultimate strain values into domestic standards. The results of experimental studies to determine the ultimate relative deformations of concrete under compression for different classes of concrete, which allowed to make analytical dependences for the evaluation of the ultimate relative deformations and description of curvilinear deformation diagrams, are presented. The article discusses various options for using the deformation model to assess the stress-strain state of the structure, it is concluded that it is necessary to use not only the finite values of the ultimate deformations, but also their intermediate values. This requires reliable diagrams "s–e” for all classes of concrete. The difficulties of measuring deformations in concrete subjected to peak load, corresponding to the prismatic strength, as well as main cracks that appeared under conditions of long-term step loading are highlighted. Variants of more accurate measurements are proposed. Development and implementation of the new standard GOST "Concretes. Methods for determination of complete diagrams" on the basis of the developed method for obtaining complete diagrams of concrete deformation under compression for the evaluation of ultimate deformability of concrete under compression are necessary.

SEISMIC ANALYSIS OF MULTISTOREY REINFORCED CONCRETE STRUCTURES

2019 ◽  
Vol 9 (1) ◽  
pp. 61
Author(s):  
SINGH RAVIKANT ◽  
KUMAR SINGH VINAY ◽  
YADAV MAHESH ◽  
◽  
◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Seismic Analysis ◽  
Concrete Structures ◽  
Reinforced Concrete Structures
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