scholarly journals Analisa Pengaruh Penggunaan Serat Serabut Kelapa dalam Presentase Tertentu pada Beton Mutu Tinggi

Author(s):  
Eduardi Prahara ◽  
Gouw Tjie Liong ◽  
Rachmansyah Rachmansyah

The use of additional material as ingredients in the manufacture of concrete mixes is increasingly growing. The material used is also increasingly varied, depending on the expected results. This research aims to know the influence of the addition of coconut fibres material with percentage of 1,5 %, 2 %, 2,5 %, and 3 % as an alternative to the strength of high-quality concrete. Research methods done by producing cylindrical and beam concrete samples for testing against the force then conducted concrete. Furthermore, the analysis has been done and the results of testing and comparing the respective strength of the composition of concrete produced. Based on the test results of data concrete cylinder compression strength and tensile strength concrete beams, it was concluded that the increasing of compressive strength up to 9% can be reached by use of additional material coconut fibers 1,5%and increasing of tensile strength up to 19,7% can be reached by use of additional coconut fiber 2%. Therefore, the additional coconut fibers on concrete mixture has strong relationship to increase tensile strength of high strength concrete.

Author(s):  
Afzal Basha Syed ◽  
Jayarami Reddy B ◽  
Sashidhar C

In present era, high-strength concrete is progressively utilized in modern concrete technology and particularly in the construction of elevated structures. This examination has been directed to explore the properties of high-strength concrete that was delivered by using stone powder (SP) as an option of extent on sand after being processed. The aim of the research is to study the effect of replacement of sand with stone powder and substitution of cement with mineral admixtures (GGBS & Zeolite) on the mechanical properties of high strength concrete. The test results showed clear improvement in compression and split tensile nature of concrete by using stone powder and mineral admixtures together in concrete. The increment in the magnitude of compressive strength and split tensile strength are comparable with conventional concrete.


Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1075 ◽  
Author(s):  
Waqas Ahmad ◽  
Syed Hassan Farooq ◽  
Muhammad Usman ◽  
Mehran Khan ◽  
Ayaz Ahmad ◽  
...  

Recently, the addition of natural fibers to high strength concrete (HSC) has been of great interest in the field of construction materials. Compared to artificial fibers, natural fibers are cheap and locally available. Among all natural fibers, coconut fibers have the greatest known toughness. In this work, the mechanical properties of coconut fiber reinforced high strength concrete (CFR-HSC) are explored. Silica fume (10% by mass) and super plasticizer (1% by mass) are also added to the CFR-HSC. The influence of 25 mm-, 50 mm-, and 75 mm-long coconut fibers and 0.5%, 1%, 1.5%, and 2% contents by mass is investigated. The microstructure of CFR-HSC is studied using scanning electron microscopy (SEM). The experimental results revealed that CFR-HSC has improved compressive, splitting-tensile, and flexural strengths, and energy absorption and toughness indices compared to HSC. The overall best results are obtained for the CFR-HSC having 50 mm long coconut fibers with 1.5% content by cement mass.


1999 ◽  
Vol 26 (2) ◽  
pp. 197-207
Author(s):  
Samir A Ashour ◽  
Sabry A Shihata ◽  
Ali A Akhtaruzaman ◽  
Faisal F Wafa

Test results of 16 rectangular prestressed high-strength concrete beams subjected to the combined action of torsion and bending are presented. The major variables were the ratio of torsion to the bending moment (T/M) and the prestressing level. The beams were subjected to two levels of prestressing, corresponding to 0.05fc' and 0.10fc', where fc' is the compressive strength of concrete (about 90 MPa). Test results showed that the torque-twist relations for the test beams were approximately linear up to cracking and thereafter became nonlinear. Increasing the T/M ratio and the prestressing level increases both torsional stiffness and strength. Several theoretical methods available in the literature developed for normal-strength concrete were used to predict the torsional strength of the tested high-strength concrete beams. Interaction equations were used along with some other methods to predict the torsional capacity in the presence of a bending moment. Good agreement was observed between the experimental and theoretical results.Key words: beams (supports), bending, cracking, failure, high-strength concrete, interaction diagram, prestressed concrete, stiffness, torsion, torsional strength.


2014 ◽  
Vol 22 (3) ◽  
pp. 1-12 ◽  
Author(s):  
Gopal Charan Behera ◽  
Tippabhotla Durga Gunneswara Rao ◽  
Chittem Butchi Kameswara

Abstract The post-cracking behaviour of structures subjected to torsion can be well predicted by Hsu’s softened truss model. The softened truss model is applicable to structures having symmetry in their material properties on all four sides. Wrapping on three faces is a common phenomenon when the top face is provided with a flange or slab. Such a wrapping on three faces of a beam is referred to as a “U” wrap. “U” wraps are better wrapping strategies for distressed structures, as their top face is not accessible for many structures. The material property of an unwrapped face differs from the rest of wrapped faces. For the effective use of wrapping, the unwrapped face needs to be provided with a material having a higher resistance to tension and shear. For this, high-strength concrete in the core is a better option. Here, an attempt is made to predict the torsional capacity of “U” wrapped high-strength concrete beams having an asymmetry in the material using a softened truss model with suitable modifications of the material properties. Efficient algorithms are proposed for the solution of simultaneous equations. The predictions are found to be in good agreement with the experimental test results


2008 ◽  
Vol 400-402 ◽  
pp. 857-863
Author(s):  
Wei Jian Yi ◽  
Yan Mei Lv

19 RC beams with shear span-to-depth equal to 3 were tested under a stiff testing facility, and complete load-deflection curves including the post-peak branch were obtained. Based on the test results the effects of concrete strength, stirrups strength, inclined stirrup angle, the amount of longitudinal reinforcement on failure mode, shear ductility index and shear capacity were analyzed. The test results were compared with the shear design approaches of Chinese Code and American Code. The results indicate that the shear failure of beam with appropriate web reinforcement has finite ductility. High-strength concrete beams with high-strength stirrups can increase not only the shear capacity, but also the shear ductility. The shear capacity of beams with high-strength concrete and stirrup can be designed with Chinese Code, but shear capacity of high-strength concrete beams without stirrups, or with the smaller amount of longitudinal reinforcement, and normal strength concrete beams with high-strength stirrups may be over-estimated by the Code.


2012 ◽  
Vol 531-532 ◽  
pp. 429-434
Author(s):  
Gang Meng ◽  
Li Hua Zhang ◽  
Jin Qing Jia

As a new type of composite structural system, the prestressed steel reinforced ultra-high strength concrete (PSRUHC) beam was applicable to large-span structures and those structures which must bearing heavy loading. But by now there is no mature calculation method for the beam with a good accuracy. So the experiment on eight post-tensioned bonded prestressed steel reinforced ultra-high strength concrete beams had been carried out to investigate the flexural performance of PSRUHC beams. Based on the test results, the flexural capacity of PSRUHC beams were analysed by the large general-purpose finite element program ANSYS. Compared the simulation results of cracking load, ultimate load, yielding load and load-displacement curve with the test results, it is proved that the numerical method is effective for analyzing flexural capacity of prestressed steel reinforced ultra-high strength concrete beams, which provides theoretical foundation for practical application of PSRUHC beam.


2018 ◽  
Vol 161 ◽  
pp. 587-597 ◽  
Author(s):  
Haitang Zhu ◽  
Shengzhao Cheng ◽  
Danying Gao ◽  
Sheikh M. Neaz ◽  
Chuanchuan Li

2011 ◽  
Vol 121-126 ◽  
pp. 126-131 ◽  
Author(s):  
Qing Lei Xu ◽  
Tao Meng ◽  
Miao Zhou Huang

In this paper, effects of nano-CaCO3 on compressive strength and Microstructure of high strength concrete in standard curing temperature(21±1°C) and low curing temperature(6.5±1°C) was studied. In order to improve the early strength of the concrete in low temperature, the early strength agent calcium nitrite was added into. Test results indicated that 0.5% dosage of nano-CaCO3 could inhibit the effect of calcium nitrite as early strength agent, but 1% and 2% dosage of nano-CaCO3 could improve the strength of the concrete by 13% and 18% in standard curing temperature and by 17% and 14% in low curing temperature at the age of 3days. According to the XRD spectrum, with the dosage up to 1% to 2%, nano-CaCO3 can change the orientation index significantly, leading to the improvement of strength of concrete both in standard curing temperature and low curing temperature.


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