Study on Frost Resistance Durability of Lightweight Aggregate Concrete Improved by Fiber

2011 ◽  
Vol 250-253 ◽  
pp. 822-827
Author(s):  
Jun Fang Huo ◽  
Hui Yang ◽  
Yong Li Hou ◽  
Jian Jun Chu ◽  
Wei Ling Li

Pumice, polypropylene fiber, steel fiber and fly ash were used to compound fiber reinforced lightweight aggregate concrete (LWAC). The effect of fibers on frost resistance durability of LWAC is studied, which including freezing-thawing in 5% Na2SO4 solution and in water. The test results show that the strength loss of LWAC is reduced with the increase in fiber fraction, but the impact of mass loss is not obvious by mixing fiber. LWAC freezing-thawing deterioration is even more serious in salt solution than in water. SEM photo show that polypropylene fiber has more stronger cementing bond with paste than steel fiber. the mass loss and strength loss are decreased significantly. By introduction silica fume can improve Interfacial Transition Zone(ITZ)and the frost resistance of fibers reinforcement LWAC dramatically.

2010 ◽  
Vol 152-153 ◽  
pp. 1565-1569
Author(s):  
Jun Fang Huo ◽  
Hui Yang ◽  
Xiang Dong Shen ◽  
Xiao Xia Ji ◽  
Qi Cui

Pumice was used to make up lightweight aggregate concrete (LWAC). Frost resistance durability of LWAC in 5% Na2SO4 solution was studied. The test results showed that LWAC durability deteriorates more rapidly under freezing-thawing in salt solution than in water. The strength loss of LWAC was reduced by steel fiber and polypropylene fiber regardless of Na2SO4 solution and water. Fly ash and silica fume can improve Interfacial Transition Zone(ITZ)and the frost resistance of fibers reinforcement LWAC dramatically.


2011 ◽  
Vol 250-253 ◽  
pp. 817-821 ◽  
Author(s):  
Jun Fang Huo ◽  
Da Peng Liu ◽  
Xiang Dong Shen ◽  
Jian Jun Chu ◽  
De Tian Song

The effect of the frost resistance on hybrid fibers reinforced lightweight aggregate concrete is investigated. And hybrid fibers reinforced lightweight aggregate is that steel fiber and polypropylene fiber are selected to incorporate into. The results indicate that, hybrid fibers reinforced lightweight aggregate concrete can improve the frost resistance. The weight loss rate of hybrid fibers reinforced lightweight aggregate concrete is not better. The research to establish a model for service life prediction of hybrid fibers reinforced lightweight aggregate concrete on experimental results has been done.


2011 ◽  
Vol 250-253 ◽  
pp. 609-613 ◽  
Author(s):  
Hong Wei Song ◽  
Hai Tao Wang

The impact resistance of steel fiber reinforced lightweight aggregate concrete was presented in a drop weight test. In this test, 5 groups of disc specimens with different steel fiber volumes including 0.0%, 0.5%, 1.0%, 1.5% and 2.0% were tested. The experimental results indicated that the impact resistance of lightweight aggregate concrete is improved with the increase in fiber volume. As the variation in experimental results, a statistical evaluation was performed to study the influence of impact resistance of steel fiber reinforced lightweight aggregate concrete with different steel fiber volumes. Further more, the impact resistance was simulated with probability distribution by Log-normal method. And the goodnees-of-fit tests indicate that the Log-normal method has good fitness to the impact resistance of steel fiber reinforced lightweight aggregate concrete.


2011 ◽  
Vol 197-198 ◽  
pp. 911-914 ◽  
Author(s):  
Li Yun Pan ◽  
Hao Yuan ◽  
Shun Bo Zhao

Tests were carried out to study mechanical properties of hybrid fiber reinforced full lightweight aggregate concrete (HFRFLAC), the hybrid fiber was composed by steel fiber and polypropylene fiber, the expanded-shale and lightweight sand were used as coarse and fine aggregates. The apparent density and strengths in cubic compressive, splitting tensile and flexural tensile states of HFRFLAC were obtained. The results show that the average dry apparent density increases with the increasing cement content, which is much more affected by fraction of steel fiber by volume than mass content of polypropylene fiber; the tensile strengths increase somewhat with the increasing mass content of polypropylene fiber; all of the strengths increase with the increasing fraction of steel fiber by volume, and obvious are the enhancement of tensile strengths; there are somewhat relevance between the effects of polypropylene fiber and steel fiber on mechanical properties of HFRFLAC.


2013 ◽  
Vol 438-439 ◽  
pp. 295-299 ◽  
Author(s):  
Xiao Ke Li ◽  
Wen Hui Song ◽  
Chang Yong Li

Compared with ordinay concrete, weight of lightweight aggregate concrete could be lower 20%-40% under same bearing capacity. Mixed with some given steel fibers in it, crack resistance and flexural strength will be improved. Once lightweight aggregate concrete mixed with steel fibers meets the requirements of frost resistance, it could be applied to most civil engineerings in a cold area. In this paper, the frost resistance mechanism of steel fiber reinforced lightweight aggregate concrete is introduced. The research status of frost resistance of steel fiber reinforced lightweight aggregate concrete is reviewed including the effects of water cement ratio, aggregate, mineral admixture and amount of fiber, frost resistance experimatal methods and engineering applications etc. Some further researches are prospected.


2014 ◽  
Vol 919-921 ◽  
pp. 1974-1978
Author(s):  
Mei Yan Hang ◽  
Cheng Xiao Sun ◽  
Pei Yu Zhang

The article studies the impact of steel fiber on the performance of lightweight aggregate concrete,including compressive strength, flexural strength, modulus of elasticity and impact toughness. The experimental studies show that steel fiber has little effect on the compressive strength of lightweight aggregate concrete, however, it can improve the pattern obviously. With the increasing of steel fiber content, the flexural strength and impact toughness of concrete increases. With the increasing of steel fiber content ,the elastic modulus of concrete also increases. The studies of this paper provide a certain technical references with the future research of steel fiber reinforced lightweight aggregate concrete.


2009 ◽  
Vol 405-406 ◽  
pp. 197-203
Author(s):  
Bao Sheng Zhang ◽  
Li Juan Kong ◽  
Yong Ge

High performance concrete (HPC) with a water/cement ratio (w/c) of 0.32 and different lightweight aggregate (LWA) contents (0%, 25%, 50%, 75%, 100%) were prepared, and the influence of LWA on concrete frost-resistance and impermeability at different ages were studied, as well as the hydration degree, hydrated product, pattern and pore structure of the paste around aggregate. The results show that, by replacing normal weight aggregate (NWA) with 50% and 100% volume contents of pre-wetted LWA respectively, the chemical bound water of the cement paste surrounding aggregate are increased 12.1% and 22.7% as compared to concrete mixed without LWA. And at 28 days, lightweight aggregate concrete has the highest Ca(OH)2 content, whereas the 90-day Ca(OH)2 content of normal weight concrete is the highest. This proves that, with the increase of LWA content in concrete, both of the internal curing effect of pre-wetted LWA and secondary hydration effect of fly ash (FA) are strengthened, this can also be verified by the SEM study. Furthermore, the pore structure of the cement paste around aggregate can be improved consequently. The performance of frost-resistance of HPC can be improved by mixing LWA, the 90 day-frost-resistance of lightweight aggregate concrete is about 2.5 times of that of concrete mixed without LWA. The influence of LWA on the impermeability of HPC is different from normal concrete. When LWA content is more than 50%, the HPC impermeability decreased obviously, however at later age the difference between them becomes minor.


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.


2019 ◽  
Vol 57 (2) ◽  
pp. 78-86
Author(s):  
Lina Xu ◽  
Lei Niu

Polypropylene fiber is widely used as a reinforcing material in composite materials of various engineering projects, because it has high strength and corrosion resistance. In this study, with the purpose of examine the impact of discrete polypropylene fiber on frost resistance of cemented soil, cemented soil treated with polypropylene fiber is used as the research sample. Firstly, the impact of curing time, fiber content and length on the strength of cemented soil has been considered. And then, the frost resistance characteristics of cemented soil reinforced by polypropylene fiber with the content of 0.5% have been investigated. The results show that with the development of curing time, the strength of cemented soil increases logarithmically. By adding an appropriate amount of polypropylene fiber, the strength of the specimen may be improved. In this study, cemented soil reinforced by polypropylene fiber 0.1% in content and 3 mm in length has the best reinforcement effect. After 21 cycles of freezing and thawing processes, a sharp decline in strength of cemented soil without fiber, and the strength loss ratio is up to 45%. There are cracks in the specimens, and some of the specimens have broken off. Differently, after 21 freeze-thaw cycles, the strength of the cemented soil with fiber decreased less, and the strength loss ratios are between 1 and 13%, and there are only small cracks on the surface of specimens. The results show that adding discrete polypropylene fiber is a suitable method to prevent the generation and development of internal cracks in the cemented soil during freezing and thawing, thereby improving the frost resistance. These results can be used as a reference for the application of cemented soil reinforced with fiber in seasonal frozen regions.


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