Influence of Freeze–Thaw Cycles on Thermal Conductivity, Water Permeability and Mechanical Properties of Asphalt Mixtures

Scientific literature mostly aims at investigation of composites with fibre hemp shives (FHS) aggregate and lime binder, although, such materials are characterised by pretty low mechanical properties. In order to obtain higher mechanical properties of a composite, it is appropriate to use cementitious binder. This work investigates physical properties of blocks from hemp shives aggregate and cementitious binder, manufactured in the expanded clay production line using vibro pressing technology. Following properties of the blocks are determined: freeze-thaw resistance, compressive strength, thermal conductivity and density. Thermal resistance according to EN ISO 6946 for the block with cavities is calculated as well. It is found that compressive strength of FHS-cement blocks may be up to 3.18 MPa when the density is of ~850 kg/m3 and thermal conductivity up to 0.135 W/(m∙K). It is found as well that the decrease of compressive strength is 8.7% after 25 freeze-thaw cycles.

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Further Investigation on Damage Model of Eco-Friendly Basalt Fiber Modified Asphalt Mixture under Freeze-Thaw Cycles

Applied Sciences ◽

10.3390/app9010060 ◽

2018 ◽

Vol 9 (1) ◽

pp. 60 ◽

Cited By ~ 18

Author(s):

Wensheng Wang ◽

Yongchun Cheng ◽

Guirong Ma ◽

Guojin Tan ◽

Xun Sun ◽

...

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Asphalt Mixture ◽

Basalt Fiber ◽

Asphalt Mixtures ◽

Splitting Tensile Strength ◽

Stiffness Modulus ◽

Freeze Thaw ◽

Damage Characteristics ◽

Indirect Tensile

The main distresses of asphalt pavements in seasonally frozen regions are due to the effects of water action, freeze-thaw cycles, and so on. Basalt fiber, as an eco-friendly mineral fiber with high mechanical performance, has been adopted to reinforce asphalt mixture in order to improve its mechanical properties. This study investigated the freeze-thaw damage characteristics of asphalt mixtures reinforced with eco-friendly basalt fiber by volume and mechanical properties—air voids, splitting tensile strength, and indirect tensile stiffness modulus tests. Test results indicated that asphalt mixtures reinforced with eco-friendly basalt fiber had better mechanical properties (i.e., splitting tensile strength and indirect tensile stiffness modulus) before and after freeze-thaw cycles. Furthermore, this study developed logistic damage models of asphalt mixtures in terms of the damage characteristics, and found that adding basalt fiber could significantly reduce the damage degree by about 25%, and slow down the damage grow rate by about 45% compared with control group without basalt fiber. Moreover, multi-variable grey models (GM) (1,N) were established for modelling the damage characteristics of asphalt mixtures under the effect of freeze-thaw cycles. GM (1,3) was proven as an effective prediction model to perform better in prediction accuracy compared to GM (1,2).

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The mechanical properties and thermal conductivity of bamboo with freeze–thaw treatment

Journal of Wood Science ◽

10.1186/s10086-021-01998-0 ◽

2021 ◽

Vol 67 (1) ◽

Author(s):

Jieyu Wu ◽

Xianke Wang ◽

Benhua Fei ◽

Xiang Xu ◽

Caiping Lian ◽

...

Keyword(s):

Mechanical Properties ◽

Thermal Conductivity ◽

Chemical Composition ◽

Moisture Content ◽

Bending Strength ◽

Testing Machine ◽

Initial Moisture Content ◽

Crystallinity Index ◽

Phyllostachys Pubescens ◽

Freeze Thaw

AbstractThe aim of this research was to investigate the effect of freeze–thaw treatment on bamboo with different initial moisture content (water-saturated, air-dried and oven-dried). Bamboo (Phyllostachys pubescens) were treated with two freeze treatments and its microstructure, chemical composition, mechanical properties and thermal conductivity were characterized by field emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), mechanical testing machine and thermal conductivity tester, respectively. The results showed that the freeze–thaw treatment had little influence on the microstructure of bamboo, the chemical composition content and the cellulose crystalline structure of bamboo were also not altered. The crystallinity index was found to increase with the increase of initial moisture content. The bending strength and elastic modulus of the treated bamboo increased, the extent of the increase was dependent on the initial moisture content and the freezing temperature. The thermal conductivity of the treated bamboo increased remarkably, which might be possibly determined by the cellulose crystallinity, moisture content, and density of bamboo.

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Effects of Thermal Conductive Materials on the Freeze-Thaw Resistance of Concrete

Materials ◽

10.3390/ma14154063 ◽

2021 ◽

Vol 14 (15) ◽

pp. 4063

Author(s):

Byeong-Hun Woo ◽

Dong-Ho Yoo ◽

Seong-Soo Kim ◽

Jeong-Bae Lee ◽

Jae-Suk Ryou ◽

...

Keyword(s):

Mechanical Properties ◽

Thermal Conductivity ◽

Silicon Carbide ◽

Steel Fiber ◽

Volume Fraction ◽

Freeze Thaw ◽

Conductive Materials ◽

Thermal Durability ◽

Negative Effect ◽

Road Paving

To solve the problem of black ice, many studies are being carried out. The key in recent days is enhancing the thermal conductivity of concrete. In this study, to improve the thermal conductivity, silicon carbide was used to substitute 50% and 100% of the fine aggregate. In addition, steel fiber is not only for enhancing the mechanical properties but could enhance thermal conductive material. Hence, the arched-type steel fiber was used up to a 1% volume fraction in this study. Furthermore, graphite was used for 5% of the volume fraction for enhancing the thermal conductivity. However, thermal damage would occur due to the difference in thermal conductivity between materials. Therefore, the thermal durability must be verified first. The target application of the concrete in this study was its use as road paving material. To evaluate the thermal durability, freeze–thaw and rapid cyclic thermal attacks were performed. The thermal conductivity of the specimens was increased with the increase in thermal conductive materials. Graphite has already been reported to have a negative effect on mechanical properties, and the results showed that this was the case. However, the steel fiber compensated for the negative effect of graphite, and the silicon carbide provided a filler effect. Graphite also had a negative effect on the freeze–thaw and rapid cyclic thermal attack, but the steel fiber compensated for the reduction in thermal durability. The silicon carbide also helped to improve the thermal durability in the same way as steel fiber. Comprehensively, the steel fiber enhanced all of the properties of the tests. Using 100% silicon carbide was considered the acceptable range, but 50% of silicon carbide was the best. Graphite decreased all the properties except for the thermal conductivity. Therefore, the content of graphite or using other conductive materials used should be carefully considered in further studies.

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An analysis of the transport properties and mechanical stability of rapidly solidified Al-Sb alloy

JOURNAL OF ADVANCES IN PHYSICS ◽

10.24297/jap.v10i2.1336 ◽

2015 ◽

Vol 10 (2) ◽

pp. 2663-2681

Author(s):

Rizk El- Sayed ◽

Mustafa Kamal ◽

Abu-Bakr El-Bediwi ◽

Qutaiba Rasheed Solaiman

Keyword(s):

Mechanical Properties ◽

Thermal Conductivity ◽

Melt Spinning ◽

Elastic Moduli ◽

Mechanical Stability ◽

Microstructural Analysis ◽

Alloy System ◽

Antimony Content ◽

The Stability ◽

Rapidly Solidified

The structure of a series of AlSb alloys prepared by melt spinning have been studied in the as meltâ€“spun ribbons Â as a function of antimony content .The stabilityÂ of these structures hasÂ beenÂ related to that of the transport and mechanical properties of the alloy ribbons. Microstructural analysis was performed and it was found that only Al and AlSb phases formed for different composition. Â The electrical, thermal and the stability of the mechanical properties are related indirectly through the influence of the antimony content. The results are interpreted in terms of the phase change occurring to alloy system. Electrical resistivity, thermal conductivity, elastic moduli and the values of microhardness are found to be more sensitive than the internal friction to the phase changes.Â

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Incorporation of Iraqi Rocks in the Production of Eco-Friendly Cement Mortar

Engineering and Technology Journal ◽

10.30684/etj.v38i10a.1479 ◽

2020 ◽

Vol 38 (10A) ◽

pp. 1522-1530

Author(s):

Rawnaq S. Mahdi ◽

Aseel B. AL-Zubidi ◽

Hassan N. Hashim

Keyword(s):

Mechanical Properties ◽

Thermal Conductivity ◽

Compressive Strength ◽

Water Absorption ◽

Structural Properties ◽

Mechanical Milling ◽

Cement Mortar ◽

Cement Mortars

This work reports on the incorporation of Flint and Kaolin rocks powders in the cement mortar in an attempt to improve its mechanical properties and produce an eco-friendly mortar. Flint and Kaolin powders are prepared by dry mechanical milling. The two powders are added separately to the mortars substituting cement partially. The two powders are found to improve the mechanical properties of the mortars. Hardness and compressive strength are found to increase with the increase of powders constituents in the cement mortars. In addition, the two powders affect water absorption and thermal conductivity of the mortar specimens which are desirable for construction applications. Kaolin is found to have a greater effect on the mechanical properties, water absorption, and thermal conductivity of the mortars than Flint. This behavior is discussed and analyzed based on the compositional and structural properties of the rocks powders.

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A Study of Some Mechanical and Physical Properties for Palm Fiber/Polyester Composite

Engineering and Technology Journal ◽

10.30684/etj.v38i3b.598 ◽

2020 ◽

Vol 38 (3B) ◽

pp. 104-114

Author(s):

Samah M. Hussein

Keyword(s):

Mechanical Properties ◽

Thermal Conductivity ◽

Dielectric Constant ◽

Date Palm ◽

Volume Fraction ◽

Unsaturated Polyester ◽

Dielectric Strength ◽

Palm Fiber ◽

Mechanical And Physical Properties ◽

Polyester Composite

This research has been done by reinforcing the matrix (unsaturated polyester) resin with natural material (date palm fiber (DPF)). The fibers were exposure to alkali treatment before reinforcement. The samples have been prepared by using hand lay-up technique with fiber volume fraction of (10%, 20% and 30%). After preparation of the mechanical and physical properties have been studied such as, compression, flexural, impact strength, thermal conductivity, Dielectric constant and dielectric strength. The polyester composite reinforced with date palm fiber at volume fraction (10% and 20%) has good mechanical properties rather than pure unsaturated polyester material, while the composite reinforced with 30% Vf present poor mechanical properties. Thermal conductivity results indicated insulator composite behavior. The effect of present fiber polar group induces of decreasing in dielectric strength, and increasing dielectric constant. The reinforcement composite 20% Vf showed the best results in mechanical, thermal and electrical properties.

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BRUSH ALLOY 3

Alloy Digest ◽

10.31399/asm.ad.cu0454 ◽

1983 ◽

Vol 32 (3) ◽

Keyword(s):

Mechanical Properties ◽

Thermal Conductivity ◽

Corrosion Resistance ◽

Physical Properties ◽

Copper Alloy ◽

Elevated Temperatures ◽

Physical And Mechanical Properties ◽

Heat Treating ◽

Good Resistance ◽

Good Corrosion Resistance

Abstract BRUSH Alloy 3 offers the highest electrical and thermal conductivity of any beryllium-copper alloy. It possesses an excellent combination of moderate strength, good corrosion resistance and good resistance to moderately elevated temperatures. Because of its unique physical and mechanical properties, Brush Alloy 3 finds widespread use in welding applications (RWMA Class 3), current-carrying springs, switch and instrument parts and similar components. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fatigue. It also includes information on corrosion resistance as well as casting, forming, heat treating, machining, joining, and surface treatment. Filing Code: Cu-454. Producer or source: Brush Wellman Inc..

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850.0 and 852.0 ALUMINUM ALLOY BEARING BARS

Alloy Digest ◽

10.31399/asm.ad.al0290 ◽

1988 ◽

Vol 37 (9) ◽

Keyword(s):

Mechanical Properties ◽

Thermal Conductivity ◽

Corrosion Resistance ◽

Aluminum Alloy ◽

Heat Treating ◽

Light Metal ◽

General Purpose ◽

High Ductility ◽

Higher Temperature ◽

Bearing Alloy

Abstract 850.0 ALUMINUM Alloy can be considered the general purpose light metal bearing alloy. Its good thermal conductivity keeps operating temperatures low. It has high ductility. In many applications it has been found to be superior to steel backed bearings. 852.0 ALUMINUM Alloy has higher mechanical properties making it suitable for heavier load and higher temperature applications. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength. It also includes information on corrosion resistance as well as heat treating and machining. Filing Code: Al-290. Producer or source: Federated Bronze Products Inc..

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