Crack Risk Evaluation of Early Age Concrete Based on the Distributed Optical Fiber Temperature Sensing

Shi, Nannan; Chen, Yanyu; Li, Zhenbao

doi:10.1155/2016/4082926

Cited by 16 publications

(11 citation statements)

References 9 publications

(16 reference statements)

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“…Because the surface of the structure radiates heat into the atmosphere, a thermal gradient occurs between the cold exterior of the structure or element and the warm core. Differences in free thermal expansion between parts of the structure will cause tensile stress on the surface [1][2][3][4]. If these stresses exceed the tensile strength of the concrete, cracking can occur.…”

Section: Introductionmentioning

confidence: 99%

Influence of Microfibers Additive on the Self-healing Performance of Mass Concrete

Dahesh

Othman²,

Abdul-Hamead³

2021

ETJ

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Because cracks are the main problem of mass concrete, this paper investigates an experimental study on the effect of polypropylene microfiber (PPMFs) on self -repair behavior of mass concrete, through study the microstructure, workability, physical, and mechanical properties of mass concrete. PPMFs with a diameter of 18 µm add in different percentages (0, 0.5, 1 and 1.5) % of cement weight. Where the prepared mixture ratio was (1:2:4.8) and the water-cement ratio (W/C) was 0.4. Also, 0.6% of Superplasticizer (SP) % of cement weight to all concrete mixtures was added. In this study, an SEM analysis used to observe the effect of PPMFs on the microstructure of mass concrete, and compressive and flexural strength tests for study the mechanical properties of this. And referring to the analysis and discussion of the results, PPMFs used have changed the microstructure of mass concrete, and have an effective effect on improving compressive strength and flexural strength, and mechanism of sealing the cracks of concrete autogenously. Also, 1% PPMFs (% of cement weight) recorded as the highest addition, which has a positive effect on mass concrete properties to apply it in the construction field.

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Section: Introductionmentioning

confidence: 99%

Influence of Microfibers Additive on the Self-healing Performance of Mass Concrete

Dahesh

Othman²,

Abdul-Hamead³

2021

ETJ

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“…The applied speed was 0.04 mm / min. The results were recorded for ready-made concrete samples at the age of 28 days [15]. To determine the flexural strength, we used the following equation:…”

Section: Flexural Strength Testmentioning

confidence: 99%

Investigation of the Effect of Microcapsule Additive on Mechanical and Physical Properties of Concrete

Salmana¹,

Abdul-Hamead²,

Othman³

2021

ETJ

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 Concrete mix has been reinforced with SiO 2 microcapsules to seal concrete cracks.  Great Self-healing capacity of concrete that contain SiO 2 microcapsules.  Crack of concrete with SiO 2 microcapsules was self-healed in 28 days.Cracks are a fundamental problem in concrete, so this research investigates an experimental study of the effect of adding SiO2 on the self-healing behaviour of concrete. The study is done by studying the physical properties, microstructure, and mechanical properties of concrete. Microcapsules were prepared to contain (cement and nano SiO 2 ) in a (palettization (fluidize bed coating) method) with (5,10, and 15) % of cement weight. The ratio of the prepared concrete mixture was (1: 2: 4) and the ratio of water to cement (W / C) 0.45 by the weight of cement was also added as 0.6% Superplasticizer to all concrete mixtures. SiO2 MC is added with (2.5) % of the cement weight in the concrete mixture. In this study, porosity, density, and water absorption tests were performed to study the physical properties, compressive and bending strength to study mechanical properties. So, referring to the results, (SiO 2 MC) was used as an effective effect in the self-healing cracking mechanism, and in improving the bending strength and compressive strength. Also, 10 % wt. was recorded as the best addition because it has a positive effect on properties to be applied in construction.

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“…It is important, however, to stress that there are other distributed fibre optic measuring systems that can be used to obtain temperature distribution in concrete elements, often with greater precision and spatial resolution than BOTDR. This includes Brillouin scattering based double ended systems such as Brillouin Optical Time Domain Analysis (BOTDA) [ 22 ] or Raman scattering based systems known as distributed temperature sensing (DTS) systems [ 32 , 33 ]. Commercial DTS systems can only measure temperature but with higher accuracy and precision than Brillouin scattering based systems.…”

Section: Measuring Principle Of the Fibre Optic Sensing Technique mentioning

confidence: 99%

Integrity Testing of Pile Cover Using Distributed Fibre Optic Sensing

Rui

Kechavarzi

O'Leary

et al. 2017

Sensors

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The integrity of cast-in-place foundation piles is a major concern in geotechnical engineering. In this study, distributed fibre optic sensing (DFOS) cables, embedded in a pile during concreting, are used to measure the changes in concrete curing temperature profile to infer concrete cover thickness through modelling of heat transfer processes within the concrete and adjacent ground. A field trial was conducted at a high-rise building construction site in London during the construction of a 51 m long test pile. DFOS cables were attached to the reinforcement cage of the pile at four different axial directions to obtain distributed temperature change data along the pile. The monitoring data shows a clear development of concrete hydration temperature with time and the pattern of the change varies due to small changes in concrete cover. A one-dimensional axisymmetric heat transfer finite element (FE) model is used to estimate the pile geometry with depth by back analysing the DFOS data. The results show that the estimated pile diameter varies with depth in the range between 1.40 and 1.56 m for this instrumented pile. This average pile diameter profile compares well to that obtained with the standard Thermal Integrity Profiling (TIP) method. A parametric study is conducted to examine the sensitivity of concrete and soil thermal properties on estimating the pile geometry.

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Crack Risk Evaluation of Early Age Concrete Based on the Distributed Optical Fiber Temperature Sensing

Cited by 16 publications

References 9 publications

Influence of Microfibers Additive on the Self-healing Performance of Mass Concrete

Influence of Microfibers Additive on the Self-healing Performance of Mass Concrete

Investigation of the Effect of Microcapsule Additive on Mechanical and Physical Properties of Concrete

Integrity Testing of Pile Cover Using Distributed Fibre Optic Sensing

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