scholarly journals Assessment of Performance of Fiber Reinforced Geopolymer Composites by Experiment and Simulation Analysis

2019 ◽  
Vol 9 (16) ◽  
pp. 3424 ◽  
Author(s):  
Khoa V. A. Pham ◽  
Tan Khoa Nguyen ◽  
Tuan Anh Le ◽  
Sang Whan Han ◽  
Gayoon Lee ◽  
...  

In this work, the experimental and simulation analysis of the performance of geopolymer composites reinforced with steel fiber and polypropylene fiber is investigated. By embedding hooked end steel fiber and polypropylene fiber with various volume fractions of 0%, 0.5%, 1%, 1.5% to the geopolymer concrete mixture, the mechanical behavior was enhanced significantly through experimental results. The compressive strength was improved 26% with 0.5% of polypropylene fiber and 46% with 1% of hooked end steel fiber while the increment of splitting tensile strength was 12% and 28%, respectively. The flexural strength of specimens using two fiber types was also improved when compared with the non-fiber geopolymer concrete. The highest increment obtained with 1.5% of fiber volume content was from 26% to 42%. The compressive performance and flexural performance of fiber-reinforced geopolymer concrete were also better than specimens without fiber, with a higher load carrying capacity, higher stress, higher toughness and smaller strain. Using hooked end steel fiber resulted in better mechanical strength than using polypropylene fiber, and the presence of fibers is an important factor related to the strength improvements. A finite element analysis was modeled by the ANSYS program, and this showed that the load–deflection response and crack patterns also agreed quite well with experimental results.

2021 ◽  
Vol 5 (4) ◽  
pp. 142
Author(s):  
Li Li ◽  
Hai-Xin Sun ◽  
Yang Zhang ◽  
Bo Yu

Fiber is effective in restricting cracks and improving the toughness of geopolymer composites, but few studies have focused on the surface crack characteristics of fiber-reinforced geopolymer composites. In this paper, after flexural tests of polypropylene fiber-reinforced geopolymer mortar, the surface cracking image was collected by a digital camera and cracking information was extract by deep learning. Finally, the cracking and fractal characteristics were specifically discussed. The semantic segmentation network can accurately extract surface cracks for calculating various parameters. The results showed that the mean intersection over union (mIoU) and mean pixel accuracy (mPA) of the cracks are 0.8451 and 0.9213, respectively. Generally, the crack length, width, area, and fractal dimension of the specimen are all increased with the increase in the fiber volume fraction. These crack parameters grow rapidly when the fiber content is small, and the growth of the crack parameters gradually slows down as the fiber volume fraction increases to approximately 1.5%. The highest crack parameter values were found in the geopolymer mortar, with a 0.48 water–binder ratio and 12 mm fiber length. The variation of the bottom crack length and the side crack fractal dimension can be used to represent the overall crack variation patterns. Meanwhile, the crack parameters increase with the increased fiber factor in a quadratic function. Based on these crack parameters, the critical fiber factor and dense fiber factor of polypropylene fiber-reinforced geopolymer mortar were 200 and 550, respectively. They are greater than those of fiber-reinforced Portland cementitious composites. The influence of various crack parameters on the flexural strength is in the order of the crack area, width, length, and fractal dimension.


Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 760
Author(s):  
Rihards Gailitis ◽  
Andina Sprince ◽  
Tomass Kozlovskis ◽  
Liga Radina ◽  
Leonids Pakrastins ◽  
...  

Geopolymer composites have been around only for 40 years. Nowadays, they are used in buildings and infrastructures of various kinds. A geopolymer’s main benefit is that it is a green material that is partially made by utilizing waste products. The carbon footprint from geopolymer matrix manufacturing is at least two times less than Portland cement manufacturing. Due to the nature of the geopolymer manufacturing process, there is a high risk of shrinkage that could develop unwanted micro-cracks that could reduce strength and create higher creep strains. Because of this concern, a common strategy to reduce long-term strains of the material, such as shrinkage and creep, is to add fiber reinforcement that would constrain crack development in the material. This article aims to determine how various kinds and amounts of different fiber reinforcement affect fly ash-based geopolymer composites’ creep strains in compression. Specimen mixes were produced with 1% steel fibers, 1% polypropylene fibers, 5% polypropylene fibers, and without fibers (plain geopolymer). For creep and shrinkage testing, cylindrical specimens Ø46 × 190 mm were used. The highest creep resistance was observed in 5% polypropylene fiber specimens, followed by 1% polypropylene fiber, plain, and 1% steel fiber specimens. The highest compressive strength was observed in 1% polypropylene fiber specimens, followed by plain specimens, 1% steel fiber specimens, and 5% polypropylene fiber-reinforced specimens. The only fiber-reinforced geopolymer mix with improved long-term properties was observed with 1% polypropylene fiber inclusion, whereas other fiber-introduced mixes showed significant decreases in long-term properties. The geopolymer composite mix with 1% polypropylene fiber reinforcement showed a reduction in creep strains of 31% compared to the plain geopolymer composite.


2013 ◽  
Vol 357-360 ◽  
pp. 1110-1114
Author(s):  
Dong Tao Xia ◽  
Xiang Kun Liu ◽  
Bo Ru Zhou

A set of new hybrid fiber reinforced high-performance concrete was developed and studied by experiment. The fibers incorporated the concrete are the collection of the steel fiber, modified polypropylene fiber and polypropylene with total fiber content not more than 1%. And the compressive test, splitting tensile test and the flexural toughness test were performed on eight groups of specimens. Based on the load-deflection and load-CMOD curves and the equivalent flexural tensile strength, the effect of fiber volume fraction and hybrid mode upon concrete's mechanical properties and post-peak behavior were investigated. The test results show that the mixing of the three different fibers can increase concrete's splitting tensile strength and flexural toughness more effectively with no significantly effect on compressive strength. The mixture of the three different fibers exist the optimization problem. Based on the results of the analysis, the compatible proportion of the three fibers is 0.7% steel fiber, 0.19% modified polypropylene fiber and 0.11% polypropylene fiber.


2021 ◽  
Vol 318 ◽  
pp. 03003
Author(s):  
Radhwan Alzeebaree ◽  
Arass Omer Mawlod ◽  
Dillshad K. Amen ◽  
Khaleel H. Younis ◽  
Alaa Mohammedameen

Geopolymer is a relatively new substance that has sparked a surge of research into nearly every field of geopolymers in recent years. It's still on the verge of becoming a competitive OPC concrete alternative. Mechanical, hardness, and fire resistance properties of geopolymer are exceptional. There has been no/limited research on the effect of fiber integration on fire resistance of geopolymer concrete. In fire-exposed concrete, fiber can help to resist spalling. The goal of this study is to develop materials that exhibit eco-friendly properties and better fire-resistant behavior. Moreover, the combined effect of binder materials and different fibers on the fire resistance of geopolymer concretes. According to the findings, the fire resistance of fiber-reinforced geopolymer concretes increased in the order of carbon fiber-based GPC, micro-steel fiber-based GPC, hooked steel fiber-based GPC, and polypropylene fiber-based GPC. Furthermore, as compared to slag and metakaolin-based GPC, fly ash-based GPC has greater stability and fire resistance. Fiber-reinforced GPC can also be used as a sustainable and durable building material in various construction applications where high performance is needed.


2021 ◽  
Vol 68 (1) ◽  
Author(s):  
Osamah M. G. Al-Kerttani ◽  
Ammar Mutar

AbstractThis article investigates utilization of polypropylene microfibers as reinforcement in geopolymer concrete to enhance the ductility characteristics since the geopolymer concrete is considered a brittle material. The polypropylene microfibers were added to geopolymer concrete at the fiber volume content of 0.5%, 1.0%, and 1.5%. In this article, a slump test and compressive strength were tested for geopolymer concretes to measure the effect of polypropylene microfibers on geopolymer concretes. Also, static flexural strength and dynamic loading were applied to find out the attitude of polypropylene fiber-reinforced geopolymer concrete and to measure both the deflection and number of load cycles until failure. While comparing the results with reference geopolymer concrete, all samples were tested at 28 days and, finally, a statistical test was carried out. The results concluded that the use of polypropylene microfibers improves the compressive strength and enhances the properties of polypropylene fiber-reinforced geopolymer concretes, increases the loading for the appearance of the first crack, and decreases the deflection of polypropylene fiber-reinforced geopolymer concretes compared with reference geopolymer concrete.


2021 ◽  
Vol 7 (2) ◽  
pp. 58
Author(s):  
Celal Çakıroğlu ◽  
Gebrail Bekdaş

In the recent years natural fiber reinforced composites are increasingly receiving attention from the researchers and engineers due to their mechanical properties comparable to the conventional synthetic fibers and due to their ease of preparation, low cost and density, eco-friendliness and bio-degradability. Natural fibers such as kenaf or flux are being considered as a viable replacement for glass, aramid or carbon. Extensive experimental studies have been carried out to determine the mechanical behavior of different natural fiber types such as the elastic modulus, tensile strength, flexural strength and the Poisson’s ratio. This paper presents a review of the various experimental studies in the field of fiber reinforced composites while summarizing the research outcome about the elastic properties of the major types of natural fiber reinforced composites. Furthermore, the performance of a kenaf reinforced composite plate is demonstrated using finite element analysis and results are compared to a glass fiber reinforced laminated composite plate.


2011 ◽  
Vol 477 ◽  
pp. 274-279 ◽  
Author(s):  
Yi Xu ◽  
Lin Hua Jiang ◽  
Hong Qiang Chu ◽  
Lei Chen

In this study, the effects of fiber types on the mechanical properties of lightweight aggregate concretes were investigated. Three types of fibers, namely, polypropylene fiber, steel fiber and water hyacinth (Eichhornia crassipes) fiber, and two types of lightweight aggregates, namely, expanded polystyrene and ceramsite were used. The compressive strength and splitting tensile strength of concretes were tested. The results show that both the compressive strength and the splitting tensile strength were improved by adding a reasonable volume of steel fiber and polypropylene fiber into LWAC. The addition of water hyacinth fiber had little effect on the compressive strength of LWAC, while a little increase was observed in the splitting tensile strength.


2020 ◽  
Vol 12 (2) ◽  
pp. 549
Author(s):  
Chenfei Wang ◽  
Zixiong Guo ◽  
Ditao Niu

Polypropylene-fiber-reinforced concrete impacts the early shrinkage during the plastic stage of concrete, and the fiber volume content influences the durability-related properties of concrete. The purpose of this paper was to investigate the influence of fiber volume content on the mechanical properties, durability, and chloride ion penetration of polypropylene-fiber-reinforced concrete in a chloride environment. Tests were carried out on cubes and cylinders of polypropylene-fiber-reinforced concrete with polypropylene fiber contents ranging from 0% to 0.5%. Extensive data from flexural strength testing, dry–wet testing, deicer frost testing, and chloride penetration testing were recorded and analyzed. The test results show that the addition of the fiber improves the failure form of the concrete specimens, and 0.1% fiber content maximizes the compactness of the concrete. The flexural strength of specimen C2 with 0.1% fiber shows the highest strength obtained herein after freeze–thaw cycling, and the water absorption of specimen C2 is also the lowest after dry–wet cycling. The results also indicate that increasing the fiber volume content improves the freeze–thaw resistance of the concrete in a chloride environment. Chlorine ions migrate with the moisture during dry–wet and freeze–thaw cycling. The chlorine ion diffusion coefficient (Dcl) increases with increasing fiber content, except for that of specimen C2 in a chloride environment. The Dcl during freeze–thaw cycling is much higher than that during dry–wet cycling.


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