scholarly journals Strength, Drying Shrinkage, and Carbonation Characteristic of Amorphous Metallic Fiber-Reinforced Mortar with Artificial Lightweight Aggregate

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4451
Author(s):  
Se-Jin Choi ◽  
Ji-Hwan Kim ◽  
Sung-Ho Bae ◽  
Tae-Gue Oh

This paper investigates the strength, drying shrinkage, and carbonation characteristic of amorphous metallic fiber-reinforced mortar with natural and artificial lightweight aggregates. The use of artificial lightweight aggregates has the advantage of reducing the unit weight of the mortar or concrete, but there is a concern that mechanical properties of concrete such as compressive strength and tensile strength may deteriorate due to the porous properties of lightweight aggregates. In order to improve the mechanical properties of lightweight aggregate mortar, we added 0, 10, 20, and 30 kg/m3 of amorphous metallic fibers to the samples with lightweight aggregate; the same amount of fiber was applied to the samples with natural aggregate for comparison. According to this investigation, the flow of mortar decreased as the amount of amorphous metallic fiber increased, regardless of the aggregate type. The compressive strength of lightweight aggregate mortar with 10 kg/m3 amorphous metallic fiber was similar to that of the LAF0 sample without amorphous metallic fiber after 14 days. In addition, the flexural strength of the samples increased as the amount of amorphous metallic fiber increased. The highest 28-d flexural strength was obtained as approximately 9.28 MPa in the LAF3 sample, which contained 30 kg/m3 amorphous metallic fiber. The drying shrinkage of the samples with amorphous metallic fiber was smaller than that of the sample without amorphous metallic fiber.

2020 ◽  
Vol 10 (10) ◽  
pp. 3519 ◽  
Author(s):  
Chao-Wei Tang

In this study, the effects of individual and mixed fiber on the mechanical properties of lightweight aggregate concrete (LWC) after exposure to elevated temperatures were examined. Concrete specimens were divided into a control group (ordinary LWC) and an experimental group (fiber-reinforced LWC), and their compressive strength, elastic modulus, and flexural strength after heating to high temperatures of 400–800 °C were investigated. The four test parameters included concrete type, concrete strength, fiber type, and targeted temperature. The test results show that after exposure to 400–800 °C, the variation in mechanical properties of each group of LWC showed a trend of increasing first and then decreasing. After exposure to 400 °C, the residual mechanical properties of all specimens did not attenuate due to the drying effect of the high temperature and the more sufficient cement hydration reaction. However, after exposure to 800 °C, the residual mechanical properties significantly reduced. Overall, the mixed fiber-reinforced LWC showed a better ability to resist the loss of mechanical properties caused by high temperature. Compared with the loss of compressive strength, the flexural strength was relatively lost.


2014 ◽  
Vol 496-500 ◽  
pp. 2402-2406
Author(s):  
Kui He ◽  
Hui Yang ◽  
Fang Fang Jia ◽  
Er Po Wang ◽  
Zhen Bao Lu ◽  
...  

Workability, strength and fracture mechanics of polypropylene macro-fiber reinforced Reactive powder concrete (RPC) were studied in this work. The results showed that the incorporation of macro-fiber could influence the workability of RPC, the slump of RPC decreased with the increasing of macro-fiber content; compressive strength decreased while splitting strength increased with the increasing of macro-fiber, meanwhile the flexural strength invariant. Macro-fiber could strongly enhance the flexural toughness of RPC and changed the failure mode from brittle to ductile; fracture energy tends to increase linearly with the increasing of macro-fiber.


Author(s):  
Christopher Collins ◽  
Saman Hedjazi

In the present study, a non-destructive testing method was utilized to assess the mechanical properties of lightweight and normal-weight concrete specimens. The experiment program consisted of more than a hundred concrete specimens with the unit weight ranging from around 850 to 2250 kg/m3. Compressive strength tests were performed at the age of seven and twenty eight days. Ultrasonic Pulse Velocity (UPV) was the NDT that was implemented in this study to investigate the significance of the correlation between UPV and compressive strength of lightweight concrete specimens. Water to cement ratio (w/c), mix designs, aggregate volume, and the amount of normal weight coarse and fine aggregates replaced with lightweight aggregate, are the variables in this work. The lightweight aggregate used in this study, Poraver®, is a product of recycled glass materials. Furthermore, the validity of the current prediction methods in the literature was investigated including comparison between this study and an available expression in the literature on similar materials, for calculation of mechanical properties of lightweight concrete based on pulse velocity. It was observed that the recently developed empirical equation would better predict the compressive strength of lightweight concrete specimens in terms of the pulse velocity.


2011 ◽  
Vol 374-377 ◽  
pp. 1499-1506
Author(s):  
Rong Hui Zhang ◽  
Jian Li

In this study, the effect of micro-expansion high strength grouting material (EGM) and Modified polypropylene coarse fiber (M-PP fiber) on the mechanical properties of lightweight concrete are investigated. The influence of EGM and M-PP fiber on compressive strength , flexural strength and drying shrinkage of concrete are researched, and flexural fracture toughness are calculated. Test results show that the effect of EGM and M-PP fiber volume fraction (Vf) on flexural strength and fracture toughness is extremely prominent, compressive strength is only slightly enhanced, and the rate of shrinkage is obviously decreased. It is observed that the shape of the descending branch of load-deflection and the ascending branch of shrinkage-age tends towards gently with the increase of Vf. And M-PP fiber reinforced lightweight aggregate concrete is more economical.


2009 ◽  
Vol 610-613 ◽  
pp. 69-75
Author(s):  
Yuan Hua ◽  
Tai Quan Zhou

Different kinds of fiber are used to reinforce the concrete to improve the concrete mechanical properties. The high modulus and high flexibility fibers are often used to reinforce in the cement base, which leads to the higher performance compound cement based materials. In the paper, the carbon fiber and glass fiber material are used as flexibility reinforced materials. The polypropylene fiber and the polyethylene fiber are used as strength reinforced materials. The combinations of the flexibility reinforced fiber and strength reinforced fiber are chosen as C-P HF (Carbon and Polypropylene Hybrid Fiber) and G-Pe HF (Glass and Polyethylene Hybrid Fiber). The concrete mixture ratio and the fiber-reinforced amount are determined to the author’s previous study. The relationship between compressive strength, flexural strength and length/diameter aspect ratio of fiber for the carbon and polypropylene hybrid fiber reinforced concrete (C-P HFRC), and for the glass and polyethylene hybrid fiber reinforced concrete (G--Pe HFRC) was tested and discussed. The testing results show that length/diameter aspect ratio of fiber obviously affects the flexural strength of C-P HFRC and G-Pe HFRC, though the compressive strength is slightly affected by the length-diameter aspect ratio.


2013 ◽  
Vol 454 ◽  
pp. 242-245 ◽  
Author(s):  
Wei Ouyang ◽  
Guang Long Geng ◽  
Mao Lin ◽  
Xiao Qing Yu

Airport pavement surface mechanical characteristics and PVA fiber content, through experiments on PVA fiber reinforced cement matrix composites flexural strength, compressive strength and other mechanical properties are analyzed experimentally.


2021 ◽  
Vol 31 (1) ◽  
pp. 139-160
Author(s):  
Mehdi Khoshvatan ◽  
Majid Pouraminia

Abstract In the paper, the effects of different percentages of additives (perlite, LECA, pumice) on the mechanical properties of structural lightweight aggregate concrete were tested and evaluated. For the research, 14 mixing designs with different amounts of aggregate, water, and cement were made. Experimental results showed that the specific gravity of lightweight structural concrete made from a mixture of LECA, pumice, and perlite aggregates could be 25-30% lighter than conventional concrete. Lightweight structural concrete with a standard specific gravity can be achieved by using a combination of light LECA with perlite lightweight aggregates (LA) and pumice with perlite in concrete. The results indicated that LECA lightweight aggregates show more effective behavior in the concrete sample. Also, the amount of cement had a direct effect on increasing the strength regardless of the composition of LAs. The amount of cement causes compressive strength to increase. Furthermore, the stability of different experimental models increased from 156 to 345 kg m 3 while increasing the amount of cement from 300 to 400 kg m 3 in the mixing designs of LECA and perlite for W/C ratios of 0.3, 0.35, and 0.4. For a fixed amount of cement equal to 300 kg, the compressive strength is reduced by 4% by changing the water to cement ratio from 0.5 to 0.4. The compression ratios of strength for 7 to 28 days obtained in this study for lightweight concrete were between 0.67-0.8. Based on the rate of tensile strength to compressive strength of ordinary concretes, which is approximately 10, this ratio is about 13.5 to-17.8 in selected and optimal lightweight concretes in this research, which can be considered good indirect tensile strength for structural lightweight concretes.


2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
Yoo-Jae Kim ◽  
Jiong Hu ◽  
Soon-Jae Lee ◽  
Byung-Hee You

Fiber reinforced aerated lightweight concrete (FALC) was developed to reduce concrete's density and to improve its fire resistance, thermal conductivity, and energy absorption. Compression tests were performed to determine basic properties of FALC. The primary independent variables were the types and volume fraction of fibers, and the amount of air in the concrete. Polypropylene and carbon fibers were investigated at 0, 1, 2, 3, and 4% volume ratios. The lightweight aggregate used was made of expanded clay. A self-compaction agent was used to reduce the water-cement ratio and keep good workability. A surfactant was also added to introduce air into the concrete. This study provides basic information regarding the mechanical properties of FALC and compares FALC with fiber reinforced lightweight concrete. The properties investigated include the unit weight, uniaxial compressive strength, modulus of elasticity, and toughness index. Based on the properties, a stress-strain prediction model was proposed. It was demonstrated that the proposed model accurately predicts the stress-strain behavior of FALC.


2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Chaohua Jiang ◽  
Yizhi Wang ◽  
Wenwen Guo ◽  
Chen Jin ◽  
Min Wei

With great mechanical properties and corrosion resistance, amorphous alloy fiber (AAF) is a highly anticipated material in the fiber-reinforced concrete (FRC) field. In this study, the mechanical properties of AAFRC such as compressive strength, tensile strength, and flexural strength were examined. The comparison and analysis between AAFRC and steel fiber-reinforced concrete (SFRC) were also carried out. The results show that adding fibers significantly improves the concrete strength and toughness index. Compared with plain concrete, the compressive strength, splitting tensile strength, and flexural strength of AAFRC increase by 8.21–16.72%, 10.4–32.8%, and 18.12–45.21%, respectively. Meanwhile, the addition of AAF with a greater tensile strength and larger unit volume quantity improves the splitting tensile strength and flexural strength of concrete more noticeably than that of SF. Adding AAF improves the ductility of concrete more significantly in comparison to the SF. AAFRC shows great interfacial bonding performance as well. A prediction equation for the strength of AAFRC was proposed, which verified good accuracy calibrated based on the test results.


2007 ◽  
Vol 280-283 ◽  
pp. 1721-1724
Author(s):  
Feng Xing ◽  
Fa Guang Leng ◽  
Wei Wen Li

The effects of Cemfiber on the workability, mechanical properties, resistance to chemical corrosion and drying shrinkage of High-Performance Concrete (HPC) have been studied systematically. The results show that: (1) the effects of Cemfiber on the workability of HPC are related to parameter of mix proportion. Generally speaking, Cemfiber does not reduce the workability of HPC; (2) the effect of Cemfiber on the compressive strength and flexural strength is very small; (3) the HPC incorporated with Cemfiber has high resistance to corrosion of hydrochloric acid; (4) Cemfiber may reduce drying shrinkage of HPC significantly; (5) Cemfiber may increase cracking resistance of HPC resulting from drying shrinkage.


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