Study on autogenous shrinkage stress considering dependence on temperature in early age

2014 ◽  
pp. 663-667
Author(s):  
Jun-ichi Arai ◽  
Takahiro Ajichi ◽  
Toshiaki Mizobuchi
Keyword(s):  
Autogenous Shrinkage ◽  
Shrinkage Stress ◽  
Early Age

Effect of the Expansion Agent on Early-Age Autogenous Shrinkage Stress of Concrete

2013 ◽  
Vol 838-841 ◽  
pp. 564-568
Author(s):  
Pan Xiu Wang
Keyword(s):  
Tensile Strength ◽  
Concrete Structure ◽  
High Performance ◽  
High Performance Concrete ◽  
Autogenous Shrinkage ◽  
Shrinkage Strain ◽  
Shrinkage Stress ◽  
Early Age ◽  
Concrete Cube

Early-age autogenous shrinkage is key problem of high performance concrete. It can cause a lot of early-age cracks in concrete structure and further endanger the permeability and durability. Adding expansion agent can control the early-age autogenous shrinkage strain and reduce the risk of early-age cracks. In this paper, the early-age autogenous shrinkage stress of concrete cube is calculated. The results show that, early-age autogenous shrinkage stress is larger than early-age tensile strength of concrete. So some cracks occur on the surface of concrete structure. By adding expansion agent, the early-age autogenous shrinkage strain and stress both decreases.

The Influence of Chemical Admixtures on the Autogenous Shrinkage Ultra-High Performance Concrete

2010 ◽  
Vol 452-453 ◽  
pp. 725-728 ◽  
Author(s):  
Jung Jun Park ◽  
Sung Wook Kim ◽  
Gum Sung Ryu ◽  
Kwang Myung Lee
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Autogenous Shrinkage ◽  
Pulse Velocity ◽  
Reducing Agent ◽  
Shrinkage Stress ◽  
Early Age ◽  
Ultra High Performance Concrete ◽  
Expansive Additive ◽  
Shrinkage Reducing Agent

Ultra-high performance concrete (UHPC) is a material developing remarkable performance with compressive strength of about 200 MPa and flexural strength of approximately 30 MPa on which research is actively conducted today. However, UHPC is also characterized by a mixing composed of a high specific quantity of binder that is a W/B ratio of about 0.2, which requires to examine the effects of the autogenous shrinkage. Accordingly, this study investigates the effects of the use of expansive additive and water reducing agent on the autogenous shrinkage of UHPC at early age. To that goal, autogenous shrinkage test and ultrasonic pulse velocity (UPV) monitoring are conducted for a mixing of UHPC using expansive additive and shrinkage reducing agent. The experimental results reveal that the autogenous shrinkage of UHPC reduces by 24% for a mix of UHPC adopting both 7.5% of expansive additive and 1% of shrinkage reducing agent compared to the mix without admixture. Furthermore, this mix is seen to compensate the autogenous shrinkage occurring at early age when UHPC develops its largest stiffness in view of the UPV evolution curve. At that time, the shrinkage stress seems to be extremely softened.

scholarly journals Synergistic Benefits of Using Expansive and Shrinkage Reducing Admixture on High-Performance Concrete

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2514 ◽  
Author(s):  
Tian-Feng Yuan ◽  
Seong-Kyum Kim ◽  
Kyung-Teak Koh ◽  
Young-Soo Yoon
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
High Performance Concrete ◽  
Autogenous Shrinkage ◽  
Shrinkage Stress ◽  
Early Age ◽  
Test Results ◽  
Shrinkage Cracking ◽  
Shrinkage Cracks ◽  
Shrinkage Reducing Admixture

High-performance concrete (HPC) is widely used in construction according to great mechanical properties, but it has a high risk of shrinkage cracking due to autogenous shrinkage stress. Therefore, the aim of this research was to investigate the effect of a combination of expansive admixture (EA) and shrinkage reducing admixture (SA) on the autogenous shrinkage of high-performance concrete without heat treatment. Two different EA to cement weight ratios of 0.0, 5.0%, and two different SA to cement weight ratios of 0.0, and 1.0% were combined and considered. To investigate the differences in the time-zero conditions effect on the autogenous shrinkage behaviors, four different initial points were compared. The test results indicate that the EA and/or SA content was conductive to a little bite increase compressive strength (22.6–37.9%) and tensile strength (<4.8%). According to the synergistic effect of the EA and SA on the HPC, the autogenous shrinkage significantly decreased (<50%), as compared to those specimens with only one type of admixture (EA or SA). Furthermore, all the specimens incurred restrained autogenous shrinkage cracks at an early age, except the specimen using the combined EA and SA. Therefore, it can be concluded that the combination of EA and SA is effective for improving the properties of HPC.

scholarly journals Evaluation of the Thermal and Shrinkage Stresses in Restrained High-Performance Concrete

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3680 ◽  
Author(s):  
Yang Yang ◽  
Linhao Ma ◽  
Jie Huang ◽  
Chunping Gu ◽  
Zhenjian Xu ◽  
...  
Keyword(s):  
Thermal Stress ◽  
High Performance ◽  
High Performance Concrete ◽  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Shrinkage Stress ◽  
Early Age ◽  
Volume Deformation ◽  
Curing Conditions ◽  
Drying Shrinkage Stress

The early age volume deformation is the main course for the cracking of high-performance concrete (HPC). Hence, the shrinkage behavior and the restrained stress development of HPC under different restraints and curing conditions were experimentally studied in this paper. The method to separate the stress components in the total restraint stress was proposed. The total restrained stress was separated into autogenous shrinkage stress, drying shrinkage stress and thermal stress. The results showed that the developments of the free shrinkage (autogenous shrinkage and drying shrinkage) and the restrained stress were accelerated when the drying began; but the age when the drying began did not significantly influence the long-term shrinkage and restrained stress of HPC; the autogenous shrinkage stress continuously contributed to the development of the total restrained stress in HPC; the drying shrinkage stress developed very rapidly soon after the drying began; and the thermal stress was generated when the temperature dropped. The thermal stress was predominant at the early age, but the contributions of the three stresses to the total restrained stress were almost the same at the age of 56 d in this study.

Early-Age Autogenous Shrinkage of High-Performance Concrete Columns by Embedded Fiber Bragg-Grating Sensor

2009 ◽  
Vol 419-420 ◽  
pp. 1-4 ◽  
Author(s):  
Ying Wei Yun ◽  
Ii Young Jang ◽  
Seong Kyum Kim ◽  
Seung Min Park
Keyword(s):  
Fiber Bragg Grating ◽  
High Performance ◽  
High Performance Concrete ◽  
Construction Material ◽  
Autogenous Shrinkage ◽  
Strain Sensor ◽  
Bragg Grating ◽  
Early Age ◽  
Long Time ◽  
Sensor Temperature

High-performance concrete (HPC) as a promising construction material has been widely used in infrastructures and high-rise buildings etc. However, its pretty high autogenous shrinkage (AS) especially in its early age becomes one of the key problems endangering long-time durability of HPC structures. This paper carried out the early age AS research of large scaled HPC column specimens by embedded Fiber Bragg-Grating (FBG) strain sensor. Temperature compensation for FBG strain sensor by thermocouple was also attempted in this paper, and the results were reasonable and acceptable comparing with the result compensated by FBG temperature sensor. Reinforcement influence, size effect and temperature effect on HPC AS were also analyzed respectively in this paper.

Properties of Autogenous Shrinkage in High-Strength Mass Concrete According to Hydration Heat Velocity

2011 ◽  
Vol 311-313 ◽  
pp. 1993-1999
Author(s):  
Kyung Mo Koo ◽  
Gyu Yong Kim ◽  
Hiroyuki Miyauchi ◽  
Yeon Woo Kang
Keyword(s):  
Autogenous Shrinkage ◽  
High Strength ◽  
Hydration Heat ◽  
Early Age ◽  
Mass Concrete ◽  
Close Relationship

The early-age properties and relationships between hydration heat and autogenous shrinkage in high-strength mass concrete are investigated through analysis of the history curves of hydration heat and autogenous shrinkage. To reduce the hydration heat velocity, micro encapsulated retarder (MR) that could retard cement reaction was applied. In the result of research, the hydration temperature and hydration heat velocity of high-strength mass concrete can be decreased with the reduction of size specimen and use of the retarder. A close relationship could be found between the hydration temperature and autogenous shrinkage; the higher the hydration heat velocity, the higher the autogenous shrinkage velocity and the greater the ultimate autogenous shrinkage.

scholarly journals Can the maturity concept be used to separate the autogenous shrinkage and thermal deformation of a cement paste at early age?

2002 ◽  
Vol 32 (9) ◽  
pp. 1443-1450 ◽  
Author(s):  
Philippe Turcry ◽  
Ahmed Loukili ◽  
Laurent Barcelo ◽  
Jean Michel Casabonne
Keyword(s):  
Cement Paste ◽  
Thermal Deformation ◽  
Autogenous Shrinkage ◽  
Early Age
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