Residual compressive strength of plain and fiber reinforced concrete after exposure to different heating and cooling regimes

Author(s):  
Aref Abadel ◽  
Hussein Elsanadedy ◽  
Tarek Almusallam ◽  
Abdulaziz Alaskar ◽  
Husain Abbas ◽  
...  
2014 ◽  
Vol 5 (4) ◽  
pp. 381-398 ◽  
Author(s):  
A. Roy ◽  
U. Sharma ◽  
P. Bhargava

The purpose of this study was to investigate the effectiveness of different strengthening schemes in strengthening heat damaged reinforced concrete short columns. A series of 63 heat damaged specimens were tested under concentric compression after jacketing externally with High Strength Fiber Reinforced Concrete (HSFRC), Ferrocement (FC) and Glass Fiber Reinforced Polymer (GFRP) jackets. The specimens were subjected to various heating and cooling regimes. The overall response of strengthened specimens was investigated with reference to un-strengthened specimens in terms of axial compressive strength, ductility, lateral stress-strain, and axial stress-strain behaviour. It was observed that while the GFRP jacketing is quite effective in improving compressive strength and energy dissipation, it is not capable of improving stiffness. On the contrary FC and HSFRC jacketing were mainly effective in improving stiffness property. Overall GFRP jacketing was found to be the most effective method of strengthening fire or heat damaged concrete columns.


2020 ◽  
Vol 14 (2) ◽  
pp. 6734-6742
Author(s):  
A. Syamsir ◽  
S. M. Mubin ◽  
N. M. Nor ◽  
V. Anggraini ◽  
S. Nagappan ◽  
...  

This study investigated the combine effect of 0.2 % drink cans and steel fibers with volume fractions of 0%, 0.5%, 1%, 1.5%, 2%, 2.5% and 3% to the mechanical properties and impact resistance of concrete. Hooked-end steel fiber with 30 mm and 0.75 mm length and diameter, respectively was selected for this study.  The drinks cans fiber were twisted manually in order to increase friction between fiber and concrete. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the strength performance of concrete, especially the compressive strength, flexural strength and indirect tensile strength. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the compressive strength, flexural strength and indirect tensile strength by 2.3, 7, and 2 times as compare to batch 1, respectively. Moreover, the impact resistance of fiber reinforced concrete has increase by 7 times as compared to non-fiber concretes. Moreover, the impact resistance of fiber reinforced concrete consistently gave better results as compared to non-fiber concretes. The fiber reinforced concrete turned more ductile as the dosage of fibers was increased and ductility started to decrease slightly after optimum fiber dosage was reached. It was found that concrete with combination of 2% steel and 0.2% drink cans fibers showed the highest compressive, split tensile, flexural as well as impact strength.    


2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Pu Zhang ◽  
Yiliang Huang ◽  
Yongqi Li ◽  
Jun Zhao ◽  
Hengqian Dong ◽  
...  

Ultrahigh-performance fiber-reinforced concrete (UHPFRC) is a new type of concrete with excellent performance and good application prospects. However, expensive heat curing or high-pressure curing was often adopted to ensure the sufficient compressive strength. This study focuses on improving the compressive strength and workability of UHPFRC by changing the composition materials and the mixture ratios under standard curing conditions. The 0-1 mm and 1∼3 mm sintered bauxite was adopted as coarse aggregate. UHPFRC with high compressive strength and good workability was developed by changing the water-binder ratios, by adding ground-granulated blast furnace slag (GGBFS) or fly ash, and by changing the bauxite content of different particle sizes. When the volume ratio of steel fiber was 3%, the recommend water to binder ratio was 0.194 according to this experiment, the dosage of GGBFS-replaced cement is recommended as 20%, the dosage of fly ash instead of silica fume is recommended as 30%. The recommend ratio of 0-1 mm and 1∼3 mm sintered bauxite was 1.51 : 1. Finally, a kind of UHPFRC material with a compressive strength of 152.4 MPa and a slump of 120 mm was developed under the standard curing conditions.


2011 ◽  
Vol 219-220 ◽  
pp. 1601-1607 ◽  
Author(s):  
Tammam Merhej ◽  
Xin Kai Li ◽  
De Cheng Feng

This paper presents the experimental investigation carried out to study the behavior of polypropylene fiber reinforced concrete (PPFRC) under compression and flexure. Crimped polypropylene fibers and twisted polypropylene fiber were used with 0.0%, 0.2%, 0.4% and 0.6% volume fractions. The influence of the volume fraction of each shape of polypropylene fiber on the compressive strength and flexural strength is presented. Empirical equations to predict the effect of polypropylene fiber on compressive and flexural strength of concrete were proposed using linear regression analysis. An increase of 27% in flexural strength was obtained when 0.6% volume fraction of twisted polypropylene fiber was added. It was also found that the contribution of fiber in flexural strength is more effective when twisted fibers were used. The compressive strength was found to be less affected by polypropylene fiber addition.


2014 ◽  
Vol 662 ◽  
pp. 24-28 ◽  
Author(s):  
Xi Du ◽  
You Liang Chen ◽  
Yu Chen Li ◽  
Da Xiang Nie ◽  
Ji Huang

With cooling tests on polypropylene fiber reinforced concrete and plain concrete that were initially subjected to different heating temperatures, the change of mechanical properties including mass loss, uniaxial compressive strength and microstructure were analyzed. The results show that the compressive strength of concrete tend to decrease with an increase in temperature. After experiencing high temperatures, the internal fibers of the polypropylene fiber reinforced concrete melted and left a large number of voids in it, thereby deteriorating the mechanical properties of concrete.


Author(s):  
Luis Octavio González Salcedo ◽  
Aydee Patricia Guerrero Zúñiga ◽  
Silvio Delvasto Arjona ◽  
Adrián Luis Ernesto Will

Resumen En diseño y construcción de estructuras de concreto, la resistencia a compresión lograda a los 28 días, es la especificación de control de estabilidad de la obra. La inclusión de fibras como reforzamiento de la matriz cementicia, ha permitido una ganancia en sus propiedades, además de la obtención de un material de alto desempeño; sin embargo, la resistencia a compresión sigue siendo la especificación a cumplir en la normatividad de la construcción. Las redes neuronales artificiales, como un símil de las neuronas biológicas, han sido utilizadas como herramientas de predicción de la resistencia a compresión en el concreto sin fibra. Los antecedentes en este uso, muestran que es de interés el desarrollo de aplicaciones en los concretos reforzados con fibras. En el presente trabajo, redes neuronales artificiales han sido elaboradas para predecir la resistencia a compresión en concretos reforzados con fibras de polipropileno. Los resultados de los indicadores de desempeño muestran que las redes neuronales artificiales elaboradas pueden realizar una aproximación adecuada al valor real de la propiedad mecánica, abriendo una futura e interesante agenda de investigación. Palabras ClavesResistencia a compresión; concreto reforzado con fibras; fibra de polipropileno; predicción; inteligencia artificial; redes neuronales artificiales.   Abstract In concrete structures’ design and construction, the compressive strength achieved at 28 days, is the work’s stability control specification. The inclusion of reinforcing fibers into the cementicious matrix, has allowed a gain in their properties, as well as obtaining a high performance material, however, the compressive strength remains the specification to meet the construction regulations. Artificial neural networks as a biological neurons’ simile have been used as tools for predicting the plain concrete compressive strength. The backgrounds in this application show that interest is the development of applications in fiber-reinforced concrete. In this paper, artificial neural networks have been developed to predict the compressive strength in polypropylene fiber reinforced concrete. The results of the performance indicators show that the developed artificial neural networks can perform an adequate approximation to the actual value of the mechanical property, opening an interesting future research.KeywordsCompressive strength, fiber-reinforced concrete, polypropylene fiber, prediction, artificial intelligence, artificial neural networks.


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