Creep and thermal cracking of ultra-high volume fly ash mass concrete at early age

Zhao, Zhifang; Wang, Kejin; Lange, David A.; Hougui, Zhou; Wang, Weilun; Zhu, Dongming

doi:10.1016/j.cemconcomp.2019.02.018

Cited by 78 publications

(25 citation statements)

References 9 publications

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“…In addition, the restrained expansion rate of the MgO expansion agent at 7 days should not be less than 0.015% (0.030%) under 20 • C (40 • C); the difference of restrained expansive rate at 28 and 7 days should not less than 0.015% (0.030%) under 20 • C (40 • C). Figure 1) was employed in this study, as it is the testing principle and method proposed in the literature [20,21]. The temperature-stress test used two dog-bone-shaped specimens: one was a restrained specimen, and the other was a free specimen.…”

Section: Materials and MIX Proportionsmentioning

confidence: 99%

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Tensile Creep Model of Slab Concrete Based on Microprestress-Solidification Theory

et al. 2020

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Tensile creep is an important factor affecting the early cracking resistance of concrete. The tensile creep model can effectively predict the development of tensile creep. In order to establish an appropriate tensile creep model, a temperature–stress testing machine (TSTM) was employed to test the development of temperature, deformation and restraint stress of benchmark concrete and concrete mixed with the MgO under different temperature curing modes. The development law of early age stress, strain and creep was analyzed via the test data of the TSTM. The early age tensile creep of concrete was predicted with the existing Kelvin creep model. The effect of variable temperature on creep was considered in this study, and an improved Kelvin creep model was proposed. The prediction accuracy of the two models was compared and analyzed. The results indicate that MgO has little influence on the creep and specific creep of concrete. The early age cracking resistance of MgO concrete is better than benchmark concrete. The improved Kelvin model based on the microprestress-solidification (MPS) theory predicts the early tensile creep of concrete more accurately in variable temperature conditions. These are significantly helpful for the application of the MgO expansion agent in dam engineering.

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Section: Materials and MIX Proportionsmentioning

confidence: 99%

“…During the TST, the computer recorded the temperature histories, free deformation strain (free strain) of the free specimen and restraint stress of the restrained specimen [20].…”

Section: Development Curves Under Different Temperature Curing Modesmentioning

confidence: 99%

Tensile Creep Model of Slab Concrete Based on Microprestress-Solidification Theory

et al. 2020

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“…As the above described testing system mainly allows for the effects of restrained linear shrinkage to be examined, the traditional TSTM has been recently modified and improved by numerous researchers, in order to enable thermally insulated and regulated concrete specimens to be examined. These improvements include temperature and humidity control, insulation, simultaneous measurements on restrained and unrestrained specimens, as well as the addition of a closed loop computer‐controlled system 70,82,85,88,113–122 …”

Section: State Of the Art Review Of Longitudinal Testing Devicesmentioning

confidence: 99%

“…(a) Schematic drawing of Kovler's pioneering system 87 (after Zhao et al 88 ), (b) the principle of compensation cycles 87 and (c) photograph of a similar system in operation from previous studies 89–92 …”

Section: State Of the Art Review Of Longitudinal Testing Devicesmentioning

confidence: 99%

Longitudinal restraining devices for the evaluation of structural behaviour of cement‐based materials: The past, present and prospective trends

Kanavaris

Azenha

Schlicke

et al. 2020

Strain

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The problem of thermal and shrinkage cracking in concrete has been long recognised by researchers and engineers as it can jeopardise the intended serviceability of a concrete structure. This has led researchers to develop testing devices which aim to simulate the behaviour of concrete under restrained deformations. Such devices are discerned in passive and active, depending on how concrete's movement is restrained, whilst a new type of devices has been developed to account for the combined effects of intrinsic restrained deformations and externally imposed actions. This paper presents a detailed and critical literature review on the developed restraining devices and an analysis of the capabilities, complexities and peculiarities associated with their use. Further to this, the challenges the developers of testing devices are faced with, the gaps and uncertainties with the methods found in the literature and recommendations for potential improvements in the field are discussed. K E Y W O R D Screep and shrinkage, heat of hydration, restraining devices, restraint, shrinkage cracking, thermal cracking, viscoelasticity

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“…The stages have been highlighted as concrete production at the batching plant or in-situ at the site, transportation through transit mixers, its placing using vibrators and formwork, curing of concrete, and post-construction structural health monitoring stages. Non curing (Juliafad et al, 2019) Early formwork removal (Rockstroh, 2018;Samouh et al, 2015) Plastic shrinkage (Bella et al, 2017;Ghourchian et al, 2018) Thermal cracking (Bella et al, 2017;Zhao et al, 2019) Early age cracking (Khan, Xu, Castel, & Gilbert, 2018;Safiuddin, Kaish, Woon, & Raman, 2018) Autogenous and drying shrinkage (Gilbert, Castel, Khan, South, & Mohammadi, 2018) 5 Post Construction Reinforcement and concrete corrosion (Shi, 2018;Zhou et al, 2018) Internal crack occurrence and propagation (Cai, Fu, Shang, & Shi, 2018;Dung, 2019) Moisture sensor is placed in the concrete − to monitor water content (to prevent excess addition of water during transportation), workability, and giving realtime data of the chemical characteristics of concrete.…”

Section: Problems With Current Practicesmentioning

confidence: 99%

Internet of Things (IoT) for digital concrete quality control (DCQC): A conceptual framework

Ghosh¹,

Hosseini²,

Al-Ameri³

et al. 2019

Modern Building Materials, Structures and Techniques (MBMST)

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Concreting is generally a manual, labour intensive and time-consuming process, putting additional burden on constrained resources. Current practices of concreting are wasteful, non-sustainable and end products usually lack proper quality conformance. This paper, as the first outcome of an ongoing research project, proposes concrete as an area ripe for being disrupted by new technological developments and the wave of automation. It puts forward arguments to show that The Internet of Things (IoT), as an emerging concept, has the potential to revolutionize concreting operations, resulting in substantial time savings, confidence in its durability and enhanced quality conformance. A conceptual framework for a digital concrete quality control (DCQC) drawing upon IoT is outlined; DCQC facilitates automated lifecycle monitoring of concrete, controlled by real-time monitoring of parameters like surface humidity, temperature variance, moisture content, vibration level, and crack occurrence and propagation of concrete members through embedded sensors. Drawing upon an analytical approach, discussions provide evidence for the advantages of adopting DCQC. The proposed system is of particular appeal for practitioners, as a workable solution for reducing water, energy consumption and required man-hours for concreting procedures, as well as, providing an interface for access to real-time data, site progress monitoring, benchmarking, and predictive analytics purposes.

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Creep and thermal cracking of ultra-high volume fly ash mass concrete at early age

Cited by 78 publications

References 9 publications

Tensile Creep Model of Slab Concrete Based on Microprestress-Solidification Theory

Tensile Creep Model of Slab Concrete Based on Microprestress-Solidification Theory

Longitudinal restraining devices for the evaluation of structural behaviour of cement‐based materials: The past, present and prospective trends

Internet of Things (IoT) for digital concrete quality control (DCQC): A conceptual framework

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