Identification of early-age concrete temperatures and strains: Monitoring and numerical simulation

Azenha, Miguel; Faria, Rui; Ferreira, Denise

doi:10.1016/j.cemconcomp.2009.03.004

Cited by 87 publications

(46 citation statements)

References 18 publications

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“…Glisic [10] compared a 5 "stiff" and a "soft" long-gauge fiber optic sensors embedded in fresh concrete, and noticed important 6 differences before the hardening of the concrete, but after the hardening both sensors measured the same 7 deformation. Azenha et al [11] obtained similar results with embedded vibrating wire sensors as well. 8…”

Section: Introductionsupporting

confidence: 71%

Influence of mechanical and geometrical properties of embedded long-gauge strain sensors on the accuracy of strain measurement

Calderón¹,

Glišić²

2012

Meas. Sci. Technol.

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In many civil and geotechnical applications it is of interest to monitor the strain deep inside the structure; consequently, it is necessary to embed the sensors into the structure's material. Construction and geotechnical materials, such as concrete and soil, can be affected by local defects, e.g. cracks, air pockets and inclusions. To monitor these materials at a structural level it is necessary to use long-gauge sensors. As the sensor has to be embedded in the host material, its presence causes perturbation of the strain field and influences the accuracy of the strain measurement. The aim of this research was to identify the critical parameters that influence the accuracy of the strain measurement, to study how these parameters affect the accuracy, and to give recommendations for sensor users. The study was based on finite element analysis and all involved materials were assumed to have the Möhr–Coulomb elastic, perfectly plastic behavior. A suitability of the numerical model for the analysis was verified using the experimental results of two cases reported in the literature and one on-site application. The study revealed that the most important parameters that influence the accuracy of the strain measurement are the goodness of interaction (strain transfer) between the host material and the anchor pieces of the sensor, the ratio between equivalent Young's modulus of the sensor and the Young's modulus of the host material, the radius of the anchor piece and the gauge length. The numerical model and parametric study are presented in detail along with practical recommendations.

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Section: Introductionsupporting

confidence: 71%

Influence of mechanical and geometrical properties of embedded long-gauge strain sensors on the accuracy of strain measurement

Calderón¹,

Glišić²

2012

Meas. Sci. Technol.

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“…El ensayo con el que se comparan los resultados del modelo es el realizado por Azenha et al (2009) y consiste en el monitoreo del comportamiento termo-mecánico de un hormigón a temprana edad. Dicho experimento fue llevado a cabo mediante la colocación de sensores capaces de medir temperaturas y tensiones dentro de una probeta prismática simétrica de hormigón, ver Figura 1a.…”

Section: Comparación Con Resultados Experimentalesunclassified

“…El modelo propuesto considera tres expresiones para representar el término fuente en función del grado de hidratación del cemento: el modelo propuesto por Azenha et al (2009), el propuesto por Cervera et al (1999) …”

Section: Término Fuente De Generación De Calorunclassified

Modelo de elementos finitos para el análisis térmico de estructuras hormigonadas por etapas

Croppi

Lazzaroni

2014

Obras y Proyectos

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Croppi, J.I. y Lazzaroni, M.C. (2014). Modelo de elementos finitos para el análisis térmico de estructuras hormigonadas por etapas . Obras y Proyectos 16, 51-58 IntroducciónDebido al proceso de hidratación del cemento, sumado a la baja conductividad del material y al método rápido de construcción, aparecen gradientes térmicos elevados entre el interior de la masa y la superficie exterior en estructuras de hormigón masivo. Durante el enfriamiento, debido a la presencia de restricciones interiores y exteriores, como por ejemplo las fundaciones, este gradiente térmico causa tensiones térmicas importantes. Si estas tensiones térmicas, sumadas a otras solicitaciones debido a cargas externas,

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“…The concrete strength at a construction site is estimated on the basis of the in-place maturity index and using a previously established relationship between maturity and strength (Nurse 1949;Saul 1951;Chengiu 1989;Carino 1984Carino , 1992Abdel-Jawad 2006). The compressive strength of early-age concrete can be predicted via the formula used for maturing concrete (Abdel-Jawad 2006; Azenha et al 2009Azenha et al , 2011. Conventionally, the compressive strength is predicted in one of two ways: the Nurse-Saul function using the maturity concept; or the equivalent age expression using the Arrhenius expression, which is a type of chemical reaction rate expression.…”

Section: Wireless Sensor Networkmentioning

confidence: 99%

“…However, differences in site location environments make the quality control of earlyage concrete difficult. Predicting the strength of concrete at the early curing stages in winter in Korea is beneficial because doing so can accelerate the construction process through the reduction of formwork and the structure removal period (Azenha et al 2009(Azenha et al , 2011.…”

Section: Introductionmentioning

confidence: 99%

Curing Management of Early-age Concrete at Construction Site using Integrated Wireless Sensors

Lee

Cho²,

Yang³

et al. 2014

ACT

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The quality requirements of concrete have become more stringent in recent times; therefore, the quality control of earlyage concrete has become an extremely important task at construction sites. Among the various factors affecting the quality performance of concrete, its curing temperature and compressive strength were focused upon in this study. A curing temperature management system was developed for in-place concrete that enables direct, real-time measurements and continuous monitoring of the internal temperature of concrete via an all-in-one wireless sensor network (WSN) during the early curing stages. The system can also suggest an informed decision about stripping of the formworks without having to consider the wiring at the construction site. To validate the system, its performance in monitoring curing temperature was investigated and verified by its application in indoor tests and at real construction sites. The compressive strength of concrete was predicted using several functions based on the maturity and the curing temperature. Then, a field experiment was performed to measure the curing temperature of concrete using the developed system. After fresh concrete was poured into the formworks, the WSN signals were measured at a 150-m radius from the field office. The signals were acquired for 28 days without any dispersion or interruption at the construction site. Therefore, it is concluded that the developed system can improve the measurement accuracy of concrete curing temperatures and can also be used at an actual construction site.

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Identification of early-age concrete temperatures and strains: Monitoring and numerical simulation

Cited by 87 publications

References 18 publications

Influence of mechanical and geometrical properties of embedded long-gauge strain sensors on the accuracy of strain measurement

Influence of mechanical and geometrical properties of embedded long-gauge strain sensors on the accuracy of strain measurement

Modelo de elementos finitos para el análisis térmico de estructuras hormigonadas por etapas

Curing Management of Early-age Concrete at Construction Site using Integrated Wireless Sensors

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