Characterization of Early Age Interface Properties of High-Performance Concrete Overlay and Normal Concrete Substrate

2008 ◽  
Author(s):  
Indrajit Ray ◽  
Julio F. Davalos ◽  
Tao Hong
2009 ◽  
Vol 419-420 ◽  
pp. 1-4 ◽  
Author(s):  
Ying Wei Yun ◽  
Ii Young Jang ◽  
Seong Kyum Kim ◽  
Seung Min Park

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.


Author(s):  
C. Xu ◽  
B. Y. Zhang ◽  
Z. H. Hou

<p>The application of high performance concrete has been increasingly concerned in the negative flexural region of steel‐concrete continuous composite girder because of its favorable tensile performance. However, the unclear cyclic and ultimate performance of a high performance concrete composite girder results to the problems which hinder the further application. In this case, a series of fatigue negative bending tests on HPC composite girders and fatigue push‐out tests on stud connectors in HPC were executed. The test results showed that the fatigue slip in the HPC composite girder was smaller than the normal concrete composite girder, and the fatigue life of stud in HPC was longer than the one in normal concrete. Meanwhile, according to the comparison between the stud fatigue live evaluations and test results, the AASHTO‐based evaluations were comparatively with larger safety redundancy, and JSCE was close to the test results but had smaller safety redundancy.</p>


2019 ◽  
Vol 271 ◽  
pp. 07008
Author(s):  
William Toledo ◽  
Leticia Davila ◽  
Ahmed Al-Basha ◽  
Craig Newtson ◽  
Brad Weldon

This paper investigates the shrinkage and thermal effects of an ultra-high performance concrete (UHPC) mixture proposed for use as an overlay material for concrete bridge decks. In this study, early-age and longer-term shrinkage tests were performed on the locally produced UHPC. Thermal and shrinkage effects in normal strength concrete slabs overlaid with UHPC were also observed. Early-age shrinkage testing showed that approximately 55% of the strain occurred in the plastic state and may not contribute to bond stresses since the elastic modulus of the UHPC should be small at such early ages. Thickness of the substrate and amount of reinforcing steel were important factors for shrinkage in the slabs. The thickest slab experienced greater shrinkage than thinner slabs. Comparing this slab to a thinner slab with the same reinforcement indicated that reinforcement ratio is more important than the area of steel.


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