Influence of prewetted lightweight aggregates on the behavior and cracking potential of internally cured concrete at an early age

Shen, Dejian; Jiang, Jinliang; Shen, Jiaxin; Yao, Panpan; Jiang, Guoqing

doi:10.1016/j.conbuildmat.2015.08.093

Cited by 87 publications

(10 citation statements)

References 34 publications

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“…The results indicate that, no matter the material, the restrained creep is 40–60% of the free deformation in the restrained temperature stress test, and the creep-to-free deformation ratio is approximately equal to the stress relaxation degree under the given temperature history. This 40–60% creep-to-free deformation ratio has also been observed in high performance concretes [ 2 , 3 , 41 , 42 ] whether or not the temperature histories were constant or variable. Thus, the ratio between creep and free deformation can be used as a measure of stress relaxation [ 7 ], and early-age creep could relax 40–60% of the restrained stress at early age.…”

Section: Resultssupporting

confidence: 63%

Double Feedback Control Method for Determining Early-Age Restrained Creep of Concrete Using a Temperature Stress Testing Machine

et al. 2018

Materials

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Early-age restrained creep influences the cracking properties of concrete. However, conventional creep measurements require a large number of tests to predict the restrained creep as it is influenced by the combined effects of variable temperature, creep recovery, and varying compression and tension stresses. In this work, a double feedback control method for temperature stress testing was developed to measure the early-age restrained creep of concrete. The results demonstrate that the conventional single feedback control method neglects the effect of restrained elastic deformation, thus providing a larger-than-actual creep measurement. The tests found that the double feedback control method eliminates the influence of restrained elastic deformation. The creep results from the double feedback method match well with results from the single feedback method after compensation for the effects of restrained elastic deformation is accounted for. The difference in restrained creep between the single and double feedback methods is significant for concrete with a low modulus of elasticity but can be neglected in concrete with a high modulus of elasticity. The ratio between creep and free deformation was found to be 40–60% for low, moderate, and high strength concretes alike. The double feedback control method is therefore recommended for determining the restrained creep using a temperature stress testing machine.

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Section: Resultssupporting

confidence: 63%

Double Feedback Control Method for Determining Early-Age Restrained Creep of Concrete Using a Temperature Stress Testing Machine

et al. 2018

Materials

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“…In general, considering the high porosity of lightweight aggregates, which increases their water absorption and retention capacity, several authors recommend wetting lightweight aggregates before using them in concrete. This treatment prevents mixing water intended for hydrating the cement from being absorbed [16][17][18]. Table 1 shows that the ratio between the masses of aggregates before and after each treatment was always greater than 1 except in the case of heat treatment.…”

Section: Nature and Methods Of Treatmentmentioning

confidence: 99%

Effect of oil palm shell treatment on the physical and mechanical properties of lightweight concrete

Traore

Messan

Hannawi

et al. 2018

Construction and Building Materials

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h i g h l i g h t sDifferent surface treatments are applied on oil palm shell (OPS). Effects of treated OPS on physico-mechanical properties of concrete are studied. Lime treatment increases the mechanical properties of OPS concrete. Sodium silicate treatment has not enhanced the bond between cement paste and OPS. Prewetting OPS and PVA treatment reduces the shrinkage and thermal conductivity. The overuse of natural aggregates for construction causes many environmental problems. In light of their environmental impact, the discussion has increasingly focused on using alternative plant-based materials and processes such as oil palm shells (OPS). However, previous studies show that OPS have a weak adhesion with cement paste, which results in a decrease in the physical and mechanical properties of OPS concretes. One of the solutions for this problem is to carry out a surface treatment on OPS before using them in concrete. This study has examined the influence of five treatments on the physical and mechanical properties of concrete: treatment with lime (CH), sodium silicate (SS), polyvinyl alcohol (PVA), heat treatment (TH) and OPS saturation (SAT). Lime treatment (CH) on OPS showed good improvement in the mechanical properties of concrete, compared to untreated OPS.

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“…The testing arrangement 87 is versatile and can be used not only for restrained shrinkage (both bulk drying and autogenous), including determination of the gradually increasing stress induced by restraint and cracking age, but also for classical creep tests under sustained tensile load, and finally can be used for conducting uniaxial tensile strength tests at different ages, which provide the important information about the stress/strength ratios as a function of time; it was and still is considered to be amongst the most advanced and reliable. This testing rig, alongside with the analytical interpretation of its results, served as the basis for several investigations on fibre‐reinforced and high‐performance concrete conducted by its conceptor 93–96 but also adopted by other researchers in numerous studies investigating creep, shrinkage and thermal effects in cementitious systems 89–92,97–112 . 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.…”

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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Influence of prewetted lightweight aggregates on the behavior and cracking potential of internally cured concrete at an early age

Cited by 87 publications

References 34 publications

Double Feedback Control Method for Determining Early-Age Restrained Creep of Concrete Using a Temperature Stress Testing Machine

Double Feedback Control Method for Determining Early-Age Restrained Creep of Concrete Using a Temperature Stress Testing Machine

Effect of oil palm shell treatment on the physical and mechanical properties of lightweight concrete

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

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