scholarly journals Shrinkage Mitigation of an Ultra-High Performance Concrete Submitted to Various Mixing and Curing Conditions

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3982
Author(s):  
Cédric Androuët ◽  
Jean-Philippe Charron
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Water Immersion ◽  
Autogenous Shrinkage ◽  
Early Age ◽  
Curing Conditions ◽  
Binder Ratio ◽  
Water To Binder Ratio ◽  
The Impact

Ultra-High Performance Concretes (UHPC) are cement-based materials with a very low water-to-binder ratio that present a very-high compressive strength, high tensile strength and ductility as well as excellent durability, making them very interesting for various civil engineering applications. However, one drawback of UHPC is their pretty high autogenous shrinkage stemming from their very low water-to-binder ratio. There are several options to reduce UHPC shrinkage, such as the use of fibers (steel fibers, polypropylene fibers, wollastonite microfibers), shrinkage-reducing admixtures (SRA), expansive admixtures (EA), saturated lightweight aggregates (SLWA) and superabsorbent polymers (SAP). Other factors related to curing conditions, such as humidity and temperature, also affect the shrinkage of UHPC. The aim of this paper is to investigate the impact of various SRA, different mixing and curing conditions (low to moderate mixing temperatures, moderate to high relative humidity and water immersion) as well as different curing starting times and durations on the shrinkage of UHPC. The major importance of the initial mixing and curing conditions has been clearly demonstrated. It was shown that the shrinkage of the UHPC was reduced by more than 20% at early-age and long-term when the fresh UHPC temperature was closer to 20 °C. In addition, curing by water immersion led to drastic reductions in shrinkage of up to 65% and 30% at early-age and long-term, respectively, in comparison to a 20% reduction for fog curing at early-age. Finally, utilization of a liquid polyol-based SRA allowed for reductions of 69% and 63% of early-age and long-term shrinkages, respectively, while a powder polyol-based SRA provided a decrease of 47% and 35%, respectively.

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.

scholarly journals The impact of coarse aggregate shape on the behavior of self-compacting high-performance concrete

2018 ◽  
Vol 49 ◽  
pp. 00079
Author(s):  
Krzysztof Ostrowski
Keyword(s):  
High Performance ◽  
Coarse Aggregate ◽  
High Performance Concrete ◽  
Significant Proportion ◽  
Rheological Parameters ◽  
Concrete Technology ◽  
Binder Ratio ◽  
Strength And Stiffness ◽  
Aggregate Shape ◽  
The Impact

Self-Compacting High Performance Concrete (SCHPC) presents a crucial step in the development of concrete technology. The most important features of self-consolidating concrete are flowability, segregation resistance and passing ability. Generally, the rheological properties are modified by effective superplasticisers and water to binder ratio. The aim of this study is to focus on the important aspect of the impact of shape of the coarse aggregate on fresh concrete mixture properties, strength and deformability of SCHPC. Coarse aggregate is a significant proportion of the concrete volume and therefore has a meaningful influence on its quality. By appropriate selection of the shape of the grain aggregate, it is possible to affect the rheological parameters of concrete. The results presented in this study indicated that the shape of the grains of coarse aggregate has an impact on the strength and stiffness of SCHPC. Moreover, the occurrence of irregular grains of coarse aggregate causes lower slump flow and higher plastic viscosity in comparison to concrete mixtures with regular grains only. The research presented in this article is part of the author's wider research devoted to this issue.

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.

High Performance Concrete with Ternary Binders

2018 ◽  
Vol 761 ◽  
pp. 120-123 ◽  
Author(s):  
Vlastimil Bílek ◽  
David Pytlík ◽  
Marketa Bambuchova
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Silica Fume ◽  
High Performance ◽  
Ordinary Portland Cement ◽  
High Performance Concrete ◽  
Fresh Concrete ◽  
Binder Ratio ◽  
Water To Binder Ratio ◽  
Condensed Silica Fume

Use a ternary binder for production of a high performance concrete with a compressive strengths between 120 and 170 MPa is presented. The water to binder ratio of the concrete is 0.225 and the binder is composed of Ordinary Portland Cement (OPC), condensed silica fume (CSF), ground limestone (L), fly ash (FA) and metakaoline (MK). The dosage of (M + CSF) is kept at a constant level for a better workability of fresh concrete. Different workability, flexural and compressive strengths were obtained for concretes with a constant cement and a metakaoline dosage, and for a constant dosage (FA + L) but a different ratio FA / L. An optimum composition was found and concretes for other tests were designed using this composition.

Research on Self-Desiccation at early Age of High Performance Concrete with Polypropylene Fiber

2011 ◽  
Vol 374-377 ◽  
pp. 1827-1830
Author(s):  
Wei Wei Yu ◽  
Qing Xiong ◽  
Yun Yu ◽  
Hang Lin
Keyword(s):  
Relative Humidity ◽  
High Performance ◽  
High Performance Concrete ◽  
Polypropylene Fiber ◽  
The Self ◽  
Experimental Results ◽  
Early Age ◽  
Experimental Conditions ◽  
Internal Relative Humidity ◽  
The Impact

This paper focuses on the impact which polypropylene fiber (PF) has on the self-desiccation effect at early age of high performance concrete (HPC). The experimental results indicate that PF has little influence on the Internal Relative Humidity (IRH) caused by self-desiccation effect of concrete, but can reduce early aged self-desiccation shrinkage of concrete. With the PF dosage increasing, the values of early self-desiccation shrinkage of HPC decrease first and then increase. In the experimental conditions, the value of self-desiccation shrinkage of concrete with 0.6Kg/m3 PF is the lowest one.

scholarly journals Cost-Effective High-Performance Concrete: Experimental Analysis on Shrinkage

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2730
Author(s):  
Barbara Kucharczyková ◽  
Dalibor Kocáb ◽  
Petr Daněk ◽  
Ivailo Terzijski
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Setting Time ◽  
Mechanical Strain ◽  
Cost Effective ◽  
Strain Gauges ◽  
Early Age ◽  
Dry Air ◽  
First Case

This paper focuses on the experimental determination of the shrinkage process in Self-Compacting High-Performance Concrete (SCC HPC) exposed to dry air and autogenous conditions. Special molds with dimensions of 100 mm × 60 mm × 1000 mm and 50 mm × 50 mm × 300 mm equipped with one movable head are used for the measurement. The main aim of this study is to compare the shrinkage curves of SCC HPC, which were obtained by using different measurement devices and for specimens of different sizes. In addition, two different times t0 are considered for the data evaluation to investigate the influence of this factor on the absolute value of shrinkage. In the first case, t0 is the time of the start of measurement, in the second case, t0 is the setting time. The early-shrinkage (48 h) is continuously measured using inductive sensors leant against the movable head and with strain gauges embedded inside the test specimen. To monitor the long term shrinkage, the specimens are equipped with special markers, embedded into the specimens’ upper surface or ends. These markers serve as measurement bases for the measurement using mechanical strain gauges. The test specimens are demolded after 48 h and the long term shrinkage is monitored using the embedded strain gauges (inside the specimens) and mechanical strain gauges that are placed, in regular intervals, onto the markers embedded into the specimens’ surface or ends. The results show that both types of measurement equipment give a similar result in the case of early age measurement, especially for the specimens cured under autogenous conditions. However, the early age and especially long term measurement are influenced by the position of the measurement sensors, particularly in the case of specimens cured under dry air conditions. It was proven that the time t0 have a fundamental influence on the final values of the shrinkage of investigated SCC HPC and have a significant impact on the conclusions on the size effect.

Study on Carbonization Test of Manufactured Sand Concrete

2013 ◽  
Vol 423-426 ◽  
pp. 1036-1040
Author(s):  
Da Zhen Xu ◽  
Gu Hua Li ◽  
Zhuang Zhi Liao ◽  
Hai Wei Yan
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Mineral Admixtures ◽  
Test Results ◽  
Carbonation Depth ◽  
Manufactured Sand ◽  
Carbonation Resistance ◽  
Binder Ratio ◽  
The Impact ◽  
Water Binder Ratio

To study the impact of mineral admixtures and water-binder ratio on carbonization resistance of high performance manufactured sand concrete, high performance concrete of single mixed flyash, admixing silica fume and no admixture were compounded, carbonation depth of 3d, 7d, 14d and 28d was recorded by the way of indoor test. The test results show that with the decrease of water-binder ratio, carbonation resistance of high performance manufactured sand concrete increase, and when the concrete compressive strength is over 55Mpa, carbonation resistance is good, and when water-binder ratio is lower than 0.38, the impact of mineral admixtures on the carbonation resistance can be neglected.

scholarly journals Early-Age Strength of Ultra-High Performance Concrete in Various Curing Conditions

Materials ◽  
2015 ◽  
Vol 8 (8) ◽  
pp. 5537-5553 ◽  
Author(s):  
Jong-Sup Park ◽  
Young Kim ◽  
Jeong-Rae Cho ◽  
Se-Jin Jeon
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Early Age ◽  
Ultra High Performance Concrete ◽  
Curing Conditions

Shrinkage Properties of Cement-Silica Fume Blended Pastes in Early Age

2017 ◽  
Vol 726 ◽  
pp. 521-526
Author(s):  
Di Zou ◽  
Lian Zhen Xiao ◽  
Wen Chong Shi
Keyword(s):  
Silica Fume ◽  
Rapid Growth ◽  
High Performance ◽  
High Performance Concrete ◽  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Early Age ◽  
Shrinkage Ratio ◽  
Study Results ◽  
Expansion Period

The cement-silica fume blended pastes were prepared with different silica fume (SF) dosages of 0%, 5%, 10%, and 15% at different water-binder ratios (W/B) of 0.4 and 0.5. The autogenous shrinkage (AS) and the drying shrinkage (DS) of the paste samples in the hydration period of 7d (168 hours) were measured by a new measurement technique to explore the influence of W/B and silica fume incorporation on the shrinkage in early age. The study results can provide reference for high performance concrete mix design.It is found that ether the AS or the DS of the paste samples shows a similar pattern, and the AS development with hydration time appeared a temporary expansion period after a rapid growth, especially in the samples at a higher W/B or with a lower SF content. However, the DS development did not occur obvious expansion period.Three development trends were obtained for the factors of W/B and SF content. 1) the AS and DS of the pastes mainly occurred in early ages. The lower W/B, the shorter the rapid growth periods, and the higher the shrinkage ratio of 1d to 7d. For the pastes with W/B of 0.4, the AS grew rapidly in 1d and the DS grew rapidly in the first 10h, and the AS value in 1d reached to 63.6% of 7d, and the DS value reached to 62.1% of 7d in the paste with SF of 10%. For the pastes with W/B of 0.5, the rapid growth periods of the AS and DS respectively extended to 30~33h and 12h, and the AS value in 1d reached to 60.0% of 7d, and the DS value reached to 57.2% of 7d in the paste with SF of 10%. 2) The lower W/B, the higher the shrinkage ratio of the AS to the DS. When the SF dosage is 10%, the ratio of the AS value to the DS value of 7d is 21.66%~21.15% for W/B of 0.4, and only 6.06%~5.78% for the W/B of 0.5. 3) the higher SF content results in the higher AS in cement-SF blended pastes. For the pastes with W/B of 0.4, the ratio of the AS to the DS increased from 6.98% to 30.16% with the increase of content of SF from 5% to 15% in 1d, from 15.1% to 28.19% in 3d, from 16.78% to 26.16% in 7d.

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