scholarly journals Comportamiento mecánico de secciones de hormigón y mortero = Mechanical behavior of concrete-mortar sections

2018 ◽  
Vol 4 (3) ◽  
pp. 10
Author(s):  
O. Pérez Casal ◽  
Alfonso Cobo Escamilla ◽  
M.E. Moreno Fernández ◽  
M.I. Prieto Barrio

ResumenEl objetivo del presente trabajo es comparar el comportamiento de los elementos estructurales sometidos a flexión o compresión después de haber sido reparados, mediante la sustitución del hormigón deteriorado por mortero de cemento Portland o mortero modificado con polímeros. En primer lugar, las probetas cúbicas se fabricaron con diferentes proporciones de reparación de mortero de cemento para ensayar a compresión, con los materiales colocados tanto en serie como en paralelo. Del análisis de resultados, se puede concluir que los sistemas mixtos - mortero de hormigón modificado con polímeros sometido a compresión pueden soportar cargas mayores que la reparación del mortero de cemento Portland, aunque en ningún caso pueden restaurar la capacidad de carga del hormigón. En los elementos sometidos a flexión, las vigas reparadas pueden alcanzar la resistencia inicial a la fractura de las vigas y soportar cargas aún mayores. Por lo tanto, la reparación de estructuras de cemento deterioradas con morteros de reparación es una buena alternativa, especialmente en elementos estructurales sometidos a flexión, y se realizan con morteros de cemento Portland. En las estructuras sometidas a compresión, es mejor utilizar morteros de reparación modificados con polímeros que aumentan la ductilidad cuando el mortero de reparación se ubica en serie con respecto a la carga.AbstractThe aim of the present work is to compare the behavior of structural elements subjected to bending or compression after having been repaired, by substituting the deteriorated concrete by Portland cement mortar or mortar modified with polymers. Firstly, cubic specimens were manufactured with different repair concrete-mortar proportions to be tested to compression, with the materials placed both in series and in parallel. From the results analysis, it can be concluded that mixed systems - polymer-modified concrete mortar subjected to compression can withstand greater loads than the repair Portland cement mortar, although they are in no case able to restore the load capacity of concrete. In elements subjected to bending, the repaired beams are able to achieve the initial fracture strength of the beams, and support even higher loads. Therefore, repairing deteriorated concrete structures using repair mortars is a good alternative, especially in structural elements subjected to bending, and performed using Portland cement mortars. In structures subject to compression, it is better to use repair mortars modified with polymers which increase the ductility when the repair mortar is located in series regarding the load

2021 ◽  
pp. 100182
Author(s):  
Alberto Muciño ◽  
Lauro Bucio ◽  
Eligio Orozco ◽  
Sofía Vargas ◽  
Nora A. Pérez

2021 ◽  
Vol 1090 (1) ◽  
pp. 012035
Author(s):  
Duaa Al-Faluji ◽  
Muna M. Al-Rubaye ◽  
Mohammed Salah Nasr ◽  
Ali A. Shubbar ◽  
Zainab S. Al-Khafaji ◽  
...  

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
The Huyen Nguyen ◽  
Tuan Anh Nguyen ◽  
Thien Vuong Nguyen ◽  
Van Khu Le ◽  
Thi Mai Thanh Dinh ◽  
...  

The electrical rehabilitation treatments of repair mortar were performed with tetrabutylammonium bromide salt (TBAB) at an electrical current density of 5 A/m2, using two electrolytes (0.1 M NaOH and 0.1 M Na3BO3solutions), and for two time periods (1 and 4 weeks), respectively. The average organic cation-based inhibitor’s concentration in cement mortars before and after this treatment was quantified using the UV-Vis spectroscopy. The experimental results reveal that the EICI treatment with 0.1 M Na3BO3was more effective in injecting the inhibitor and in improving the chloride penetration resistance and compressive strength of the mortar, relative to using 0.1 M NaOH as electrolyte. In this case, after the 4-week EICI treatment, [TBA+] contents were 2.3 % and 2.4% by mass of cement mortar for uncontaminated and salt-contaminated mortars, respectively. After the 4-week EICI treatment, the apparent diffusion coefficients of chloride anion in cement mortar were decreased by 40% from 1.52 × 10−10 m2/s. The EICI treatment was able to halt the chloride-induced corrosion of the steel rebar by promoting its passivation. The 2-week EICI treatment using sodium hydroxide and sodium borate solutions decreased the corrosion current density of the rebar by 77.8% and 78.5%, respectively, approximately two months after the treatment.


2014 ◽  
Vol 55 ◽  
pp. 359-364 ◽  
Author(s):  
F.J. Alejandre ◽  
V. Flores-Alés ◽  
R. Villegas ◽  
J. García-Heras ◽  
E. Morón

2014 ◽  
Vol 37 (5) ◽  
pp. 787-794 ◽  
Author(s):  
Katja Ohenoja ◽  
Sandra Breitung-Faes ◽  
Päivö Kinnunen ◽  
Mirja Illikainen ◽  
Juha Saari ◽  
...  

Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7538
Author(s):  
Wenkai Huang ◽  
Wei Hu ◽  
Tao Zou ◽  
Junlong Xiao ◽  
Puwei Lu ◽  
...  

Most existing wall-climbing robots have a fixed range of load capacity and a step distance that is small and mostly immutable. It is therefore difficult for them to adapt to a discontinuous wall with particularly large gaps. Based on a modular design and inspired by leech peristalsis and internal soft-bone connection, a bionic crawling modular wall-climbing robot is proposed in this paper. The robot demonstrates the ability to handle variable load characteristics by carrying different numbers of modules. Multiple motion modules are coupled with the internal soft bone so that they work together, giving the robot variable-step-distance functionality. This paper establishes the robotic kinematics model, presents the finite element simulation analysis of the model, and introduces the design of the multi-module cooperative-motion method. Our experiments show that the advantage of variable step distance allows the robot not only to quickly climb and turn on walls, but also to cross discontinuous walls. The maximum climbing step distance of the robot can reach 3.6 times the length of the module and can span a discontinuous wall with a space of 150 mm; the load capacity increases with the number of modules in series. The maximum load that modules can carry is about 1.3 times the self-weight.


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