scholarly journals A Mesoscopic Simulation for the Early-Age Shrinkage Cracking Process of High Performance Concrete in Bridge Engineering

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Guodong Li ◽  
Zonglin Wang
Keyword(s):  
High Performance ◽  
Damage Mechanics ◽  
High Performance Concrete ◽  
Bridge Engineering ◽  
Early Age ◽  
Crack Model ◽  
Shrinkage Cracking ◽  
Mesoscopic Simulation ◽  
Shrinkage Cracks ◽  
Cracking Process

On a mesoscopic level, high performance concrete (HPC) was assumed to be a heterogeneous composite material consisting of aggregates, mortar, and pores. The concrete mesoscopic structure model had been established based on CT image reconstruction. By combining this model with continuum mechanics, damage mechanics, and fracture mechanics, a relatively complete system for concrete mesoscopic mechanics analysis was established to simulate the process of early-age shrinkage cracking in HPC. This process was based on the dispersion crack model. The results indicated that the interface between the aggregate and mortar was the crack point caused by shrinkage cracks in HPC. The locations of early-age shrinkage cracks in HPC were associated with the spacing and the size of the aggregate particle. However, the shrinkage deformation size of the mortar was related to the scope of concrete cracking and was independent of the crack position. Whereas lower water to cement ratios can improve the early strength of concrete, this ratio cannot control early-age shrinkage cracks in HPC.

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.

An Evaluation on the Restrained Shrinkage of Ultra-High Performance Concrete

2012 ◽  
Vol 525-526 ◽  
pp. 449-452 ◽  
Author(s):  
Jung Jun Park ◽  
Doo Yeol Yoo ◽  
Sung Wook Kim ◽  
Young Soo Yoon
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Tensile Creep ◽  
Ring Test ◽  
Early Age ◽  
Restrained Shrinkage ◽  
Reinforcing Bars ◽  
Ultra High Performance Concrete ◽  
Shrinkage Cracking ◽  
Coarse Aggregates

Since ultra-high performance concrete (UHPC) is subject to large occurrence of shrinkage at early age due to its low water-to-cement ratio, the mixing of large quantities of powdered admixtures and the absence of coarse aggregates, UHPC presents large risks of shrinkage cracking caused by the restraints provided by the form and reinforcing bars. Accordingly, this study intends to evaluate the shrinkage behavior of UHPC under restrained state by performing restrained shrinkage test using ring-test. The test results reveal that increasing thickness of the inner ring increases the tensile creep at early age leading to the reduction of the average strain and residual stress of the inner ring.

Shrinkage Cracking of High Performance Concrete Mixed with Steel Slag Admixture

2011 ◽  
Vol 462-463 ◽  
pp. 867-871 ◽  
Author(s):  
Yun Feng Li ◽  
Hua Xun Guo ◽  
Ling Ling Wang
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Steel Slag ◽  
Concrete Structures ◽  
Mineral Admixtures ◽  
Maintenance Cost ◽  
Shrinkage Stress ◽  
Early Age ◽  
Restrained Shrinkage ◽  
Shrinkage Cracking

Cracking due to the restrained shrinkage stress has been frequently observed at early age in concrete structures. Early-age deterioration of concrete due to cracking and higher maintenance cost for poor durability cause serious troubles to concrete structures. Steel slag includes a certain scale mineral such as C2S and C3S, and can be applied in cement and concrete as mineral admixtures. Two tests are outlined to quantify the behaviour of concrete under restrained shrinkage using plate and ring specimens. The results show that mineral admixtures can be used to reduce cracking in concrete. The risk of cracking can be estimated for steel slag concrete, so that it will improve the durability of concrete structures.

Ring Method Test on the early-Age Anti-Cracking Capability of High-Performance Lithium Slag Concrete

2011 ◽  
Vol 94-96 ◽  
pp. 782-785
Author(s):  
Ke Bin Shi ◽  
Shan De Zhang
Keyword(s):  
Surface Area ◽  
High Performance ◽  
High Performance Concrete ◽  
Early Age ◽  
Shrinkage Cracking ◽  
Binder Ratio ◽  
Ring Method ◽  
Lithium Slag ◽  
A Current ◽  
Water Binder Ratio

Early shrinkage cracking of high performance concrete is a current hotspot of research at home and abroad.In order to make full use of local lithium-slag resources in Xinjiang,We use lithium slag as admixture of concrete to research its early-age anti-cracking capability under low water binder ratio. Ring method test on the influence of the dosage of lithium slag on its early-age anti-crak capability of concrete under the conditions of the same surface area (950m2/kg) and water binder ratio(0.27).We have obtained the best dosages of lithium slag which can resist early-age craking of concrete by monitoring concrete strain and observating concrete cracks. Therefore, the 30%dosages of lithium slag is the best for early-age anti-crack capability of concrete.

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.

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