Research on the Restraint Expansive Stress of MgO Reinforced Concrete at the Early Age

2014 ◽  
Vol 584-586 ◽  
pp. 1243-1246
Author(s):  
Jun Cheng ◽  
Hua Li ◽  
Yu Jiang Wang ◽  
Ting Yao ◽  
Si Chen Li ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
The Self ◽  
Early Age ◽  
Concrete Shrinkage ◽  
Early Age Concrete

To solve the problem of early-age concrete shrinkage under constraint, 0%, 2%, 3%MgO expansion agent are mixed in the concrete. Results indicate that MgO expansion agent can ensure the expansion strain of the concrete and produce the self-stress under constraint which is up to 1.8Mpa~2.2Mpa.

scholarly journals Effect of Reinforcement on Early-Age Concrete Temperature Stress: Preliminary Experimental Investigation and Analytical Simulation

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Jianda Xin ◽  
Siqing Lin ◽  
Nannan Shi ◽  
Jianshu Ouyang ◽  
Dahai Huang
Keyword(s):  
Reinforced Concrete ◽  
Temperature Stress ◽  
Testing Machine ◽  
Early Age ◽  
Principle Of Superposition ◽  
Stress Development ◽  
Concrete Crack ◽  
Analytical Simulation ◽  
Concrete Temperature ◽  
Early Age Concrete

For concrete under short-term loading, effect of reinforcement on concrete crack resistance capability is usually negligible; however, recent research results show that extension of this viewpoint to concrete under long-term loading (temperature variation) may be unsuitable. In order to investigate this phenomenon, this paper presents the experimental and analytical results of early-age reinforced concrete temperature stress development under uniaxial restraint. The experiments were carried out on a temperature stress testing machine (TSTM). Experimental results show that the coupling of reinforcement and concrete creep behavior influenced the concrete temperature stress development, and nearly 16% of concrete stress was reduced in the current research. Moreover, the cracking time of reinforced concrete was also delayed. Finally, based on the principle of superposition, analytical simulations of effect of reinforcement on concrete temperature stress have been performed.

scholarly journals Effect of Fibre Reinforcement on Creep in Early Age Concrete

2021 ◽  
Vol 12 (1) ◽  
pp. 257
Author(s):  
Laura González ◽  
Álvaro Gaute ◽  
Jokin Rico ◽  
Carlos Thomas
Keyword(s):  
Reinforced Concrete ◽  
Creep Strain ◽  
Creep Test ◽  
Modulus Of Elasticity ◽  
Elastic Strain ◽  
Early Age ◽  
Fibre Reinforcement ◽  
Fibre Reinforced Concrete ◽  
Strain Behaviour ◽  
Early Age Concrete

This research analyses the strain behaviour of fibre-reinforced concrete (FRC) in the event of a creep episode. The analysis of creep experienced by FRC specimens during the test reflects better performance than that predicted by the EHE-08 standard. The authors propose a formulation for the evaluation of creep strain undergone by FRC. During the research, the evolution of the modulus of elasticity of FRC after a creep episode is analysed. After the test campaign, it can be concluded that FRC loaded at an earlier age stiffens after a creep episode. After the creep test is completed, the delayed elastic strain undergone by FRC is analysed and it is observed that FRC loaded at an earlier age undergoes less deformation. The authors propose a formulation for the evaluation of the delayed elastic strain undergone by FRC after a creep episode.

Methodology of studying the mechanical properties of composite materials (reinforced concrete)

2018 ◽  
Vol 84 (12) ◽  
pp. 61-67
Author(s):  
V. A. Eryshev
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Experimental Studies ◽  
Analytical Relationship ◽  
Hardened Concrete ◽  
Deformation Model ◽  
Joint Work ◽  
Concrete Shrinkage ◽  
Axial Tension ◽  
Tension And Compression

The mechanical properties of a complex composite material formed by steel and hardened concrete, are studied. A technique of operative quality control of new credible concrete and reinforcement, both in laboratory and field conditions is developed for determination of the strength and strain characteristics of materials, as well as cohesion forces determining their joint operation under load. The design of the mobile unit is presented. The unit provides a possibility of changing the direction of loading and testing the reinforced element of the given shape both for tension and compression. Moreover, the nomenclature of testing equipment and the number of molds for manufacturing concrete samples substantially decrease. Using the values of forcing resulting in concrete cracking when the joint work of concrete and reinforcement is disrupted the values of the inherent stresses and strains attributed to the concrete shrinkage are determined. An analytical relationship between the forces and deformations of the reinforced concrete sample with central reinforcement is derived for axial tension and compression, with allowance for strains and stresses in the reinforcement and concrete resulted from concrete shrinkage. The results of experimental studies are presented, including tension diagrams and diagrams of developing axial deformations with an increase in the load under the central loading of the reinforced elements. A methodology of accounting for stresses and deformations resulted from concrete shrinkage is developed. The applicability of the derived analytical relationships between stresses and deformations on the material diagrams to calculations of the reinforced concrete structures in the framework of the deformation model is estimated.

Very early age concrete hydration characterization monitoring using piezoceramic based smart aggregates

2013 ◽  
Vol 22 (8) ◽  
pp. 085025 ◽  
Author(s):  
Qingzhao Kong ◽  
Shuang Hou ◽  
Qing Ji ◽  
Y L Mo ◽  
Gangbing Song
Keyword(s):  
Early Age ◽  
Concrete Hydration ◽  
Early Age Concrete
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