scholarly journals EXPERIMENTAL TESTING OF REINFORCED CONCRETE SLABS RETROFITTED WITH CFRP AND MECHANICAL ANCHORS

Author(s):  
GENEVIEVE PEZZOLA ◽  
LAUREN STEWART
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Radim Čajka ◽  
Zuzana Marcalíková

Abstract The presented article deals with experimental testing of fiber-reinforced concrete slabs using a specialized testing device, the so-called Stand. The experimental testing involved a total of three slabs with different fiber dosing. Dosing was chosen of 25, 50, and 75 kg/m3. In the case of fiber dosing of 75 kg/m3, the concrete recipe was changed with regard of fiber dosing. The test equipment allows vertical loading of the elements and, together with the installed track sensors and computer technology, records the vertical deformations. The deformation of the slabs was evaluated using 2D deformation sections in the slabs of mounted sensors and using 3D deformation sections with the use of interpolation of intermediate values. The article is supplemented by a test evaluation of the mechanical properties. These were concrete compressive strength, modulus of elasticity, and tensile strength. The mechanical properties were also tested and evaluated for plain concrete (dosage 0 kg/m3). By evaluating the mechanical properties and deformations, it is possible to observe differences in the behavior of fiber-reinforced concrete elements for different degrees of fiber reinforcement. The article evaluates the positive effect of fibers on the load capacity and the deformations of slabs.


Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4622
Author(s):  
Kevin Paolo V. Robles ◽  
Jurng-Jae Yee ◽  
Seong-Hoon Kee

The main objectives of this study are to evaluate the effect of geometrical constraints of plain concrete and reinforced concrete slabs on the Wenner four-point concrete electrical resistivity (ER) test through numerical and experimental investigation and to propose measurement recommendations for laboratory and field specimens. First, a series of numerical simulations was performed using a 3D finite element model to investigate the effects of geometrical constraints (the dimension of concrete slabs, the electrode spacing and configuration, and the distance of the electrode to the edges of concrete slabs) on ER measurements of concrete. Next, a reinforced concrete slab specimen (1500 mm (width) by 1500 mm (length) by 300 mm (thickness)) was used for experimental investigation and validation of the numerical simulation results. Based on the analytical and experimental results, it is concluded that measured ER values of regularly shaped concrete elements are strongly dependent on the distance-to-spacing ratio of ER probes (i.e., distance of the electrode in ER probes to the edges and/or the bottom of the concrete slabs normalized by the electrode spacing). For the plain concrete, it is inferred that the thickness of the concrete member should be at least three times the electrode spacing. In addition, the distance should be more than twice the electrode spacing to make the edge effect almost negligible. It is observed that the findings from the plain concrete are also valid for the reinforced concrete. However, for the reinforced concrete, the ER values are also affected by the presence of reinforcing steel and saturation of concrete, which could cause disruptions in ER measurements


2020 ◽  
pp. 136943322097814
Author(s):  
Xing-lang Fan ◽  
Sheng-jie Gu ◽  
Xi Wu ◽  
Jia-fei Jiang

Owing to their high strength-to-weight ratio, superior corrosion resistance, and convenience in manufacture, fiber-reinforced polymer (FRP) bars can be used as a good alternative to steel bars to solve the durability issue in reinforced concrete (RC) structures, especially for seawater sea-sand concrete. In this paper, a theoretical model for predicting the punching shear strength of FRP-RC slabs is developed. In this model, the punching shear strength is determined by the intersection of capacity and demanding curve of FRP-RC slabs. The capacity curve is employed based on critical shear crack theory, while the demand curve is derived with the help of a simplified tri-linear moment-curvature relationship. After the validity of the proposed model is verified with experimental data collected from the literature, the effects of concrete strength, loading area, FRP reinforcement ratio, and effective depth of concrete slabs are evaluated quantitatively.


2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Elena Marrocchino ◽  
Chiara Telloli ◽  
Alessandra Aprile ◽  
Domenico Capuani ◽  
Davide Malaguti ◽  
...  

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