Influences of Polypropylene Fiber on Properties of Foam Concrete with Iron Tailings

2014 ◽  
Vol 1004-1005 ◽  
pp. 1575-1578
Author(s):  
Li Guang Xiao ◽  
Chang Liu ◽  
Shi Ting Zhang
Keyword(s):  
Crack Resistance ◽  
Frost Resistance ◽  
Polypropylene Fiber ◽  
High Strength ◽  
Pore Wall ◽  
High Porosity ◽  
Foam Concrete ◽  
Insulation Property ◽  
Industrial Processing ◽  
Thermal Insulation Property

Iron tailings are mineral wastes obtained from industrial processing and magnetic separation of iron ore. Foam concrete with iron tailings can be made with iron tailings, cement, fly ash, silica fume, polypropylene fiber, superplasticizer, early strength agent, accelerating agent and foaming agent. The influences of polypropylene fiber on the crack resistance and frost resistance of foam concrete have been investigated in this study. Further, the microstructure of foam concrete was observed. This result demonstrates that polypropylene fiber has greatly increased the crack resistance and frost resistance of foam concrete. The pore structure of foam concrete is improved obviously by polypropylene fiber. Due to the uniformly distributed pores, high porosity and rather complete pore wall, the mechanical properties and thermal properties of foam concrete are excellent. The foam concrete with high-strength and excellent thermal insulation property develops a new route for the comprehensive utilization of iron tailings.

Influences of Admixtures on Properties of Foam Concrete with Iron Tailings

2014 ◽  
Vol 599 ◽  
pp. 61-65 ◽  
Author(s):  
Li Guang Xiao ◽  
Chang Liu ◽  
Shi Ting Zhang ◽  
Wen Bin Wang
Keyword(s):  
Iron Ore ◽  
Polypropylene Fiber ◽  
High Strength ◽  
High Water ◽  
Foam Concrete ◽  
Insulation Property ◽  
Foaming Agent ◽  
Industrial Processing ◽  
Early Strength ◽  
Thermal Insulation Property

Iron tailings are mineral wastes obtained from industrial processing and magnetic separation of iron ore. A type of superplasticizer with high water reducing rate and early strength gaining property is characterized in this study. The influence of admixtures, i.e. superplasticizer, early strength agent and accelerating agent, on the mechanical strength, setting and hardening time of foam concrete containing iron tailings has been investigated. Further, the microstructure of foam concrete is observed. This study demonstrates high-strength foam concrete with excellent thermal insulation property can be prepared using iron tailings, cement, fly ash, silica fume, polypropylene fiber, superplasticizer, early strength agent, accelerating agent and foaming agent, which develops a new route for the comprehensive utilization of iron tailings.

Study on Properties of Foam Concrete Based on Fractal Theory

2011 ◽  
Vol 194-196 ◽  
pp. 1916-1919 ◽  
Author(s):  
Wen Ling Tian ◽  
Jiang Bo Yang ◽  
Xiao Yan Zhao
Keyword(s):  
Fractal Dimension ◽  
Fly Ash ◽  
Thermal Insulation ◽  
Fractal Theory ◽  
High Strength ◽  
Sound Insulation ◽  
Foam Concrete ◽  
Insulation Property ◽  
Foaming Agent ◽  
Thermal Insulation Property

Foam concrete is provided with light weight, thermal insulation, sound insulation and fire resistance, good seismic performance and other characteristics. To improve properties of foam concrete microstructure is studied with the help of fractal theory, fractal dimension related to mechanical properties and thermal performance of foam concrete is calculated by MATLAB language program. The results indicate that the microstructure of foam concrete showed significant fractal character, the fractal dimension is between 1.3 and 2.0. Apparent density, 28d compressive strength, and thermal conductivity decreases with the increase of fly ash and foaming agent content, fractal dimension increased. Formulas of fractal dimension and the fly ash, foaming agent content were established. Foam concrete with low density, high strength, and good thermal insulation property will be prepared conducted by the formulas.

scholarly journals Effect of Polypropylene Fiber on Frost Resistance of Cemented Soil

2019 ◽  
Vol 57 (2) ◽  
pp. 78-86
Author(s):  
Lina Xu ◽  
Lei Niu
Keyword(s):  
Frost Resistance ◽  
Polypropylene Fiber ◽  
High Strength ◽  
Strength Loss ◽  
Curing Time ◽  
Freezing And Thawing ◽  
Cemented Soil ◽  
Small Cracks ◽  
The Impact ◽  
Engineering Projects

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.

scholarly journals Thermal insulation property of graphene/polymer coated textile based multi-layer fabric heating element with aramid fabric

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Hyelim Kim ◽  
Han Seong Kim ◽  
Sunhee Lee
Keyword(s):  
Surface Temperature ◽  
Thermal Insulation ◽  
Temperature Difference ◽  
Protective Clothing ◽  
Woven Fabrics ◽  
Heating Element ◽  
Electrical Heating ◽  
High Porosity ◽  
Insulation Property ◽  
Thermal Insulation Property

Abstract This study investigated the thermal insulation properties based on electrical heating test of graphene-based multi-layer fabric heating elements to confirm the possibility of application for fabric heating element for protective clothing. Four layers were designed as layers of outer, filler, electrical heating textile, and lining. The outer fabrics used two different densities of aramid woven fabrics (LD_ARW and HD_ARW), an aramid knit (AR_KT), and nonwoven (AR_NW). Fabricated graphene/polymer coated electrical heating textile (GR) exhibits a surface temperature of about 85 °C, a current of 0.12 A, and a power of 3 W when 30 V is applied. As composed with 4-layer, the surface temperature of LD_ARW and HD_ARW used as the outer for sample indicated less than 50 °C, due to their excellent heat resistance property; whereas, when AR_KT and AR_NW were used, the temperature was about 50 °C. This is because their fine fibers form high porosity that can entrap air. As a result of the thermal insulation properties, the temperature difference of each layer was in the order ΔT(GR-N3) < ΔT(GR-Lining) < ΔT(GR-Outer). In particular, when AR_NW was used as the outer fabric, ΔT(GR-Outer) was decreased by about 10 °C, compared with that of the other outer fabric. By the effect of relative humidity under dry 25% RH and comfortable 55% RH, the temperature difference was decreased under 55% RH; thus, the thermal insulation property was improved under comfortable humidity condition. Therefore, the best thermal insulation performance was exhibited when AR_NW was used as outer under 55% RH, and it is expected to expand its application to fabric heating element for protective clothing.

scholarly journals Preparation of Ultrafine Fly Ash-Based Superhydrophobic Composite Coating and Its Application to Foam Concrete

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2187
Author(s):  
Huiping Song ◽  
Mingxiu Tang ◽  
Xu Lei ◽  
Zhengjun Feng ◽  
Fangqin Cheng
Keyword(s):  
Fly Ash ◽  
Composite Coating ◽  
Water Drop ◽  
Heat Conductivity Coefficient ◽  
Foam Concrete ◽  
Large Area ◽  
Sliding Angle ◽  
Insulation Property ◽  
Foamed Concrete ◽  
Thermal Insulation Property

The waterproof and thermal insulation property of foamed concrete is very important. In this study, the ultrafine fly ash (UFA)-based superhydrophobic composite coating was applied onto foam concrete. The UFA-based base coating that closely adhered to the concrete initially improved the waterproofness of the test block, and the silane coupling agent-modified UFA-based surface coating further achieved superhydrophobicity. The UFA on the coating surface and the asperities on the surface jointly formed a lotus leaf-like rough micro–nanostructure. The 154.34° water drop contact angle and 2.41° sliding angle on No. 5 coating were reached, indicating that it was a superhydrophobic surface. The water absorption ratios of the composite coating block were 1.87% and 16.6% at 4 h and 7 days, which were reduced by 97% and 75% in comparison with the original foam concrete. The compressive strength and heat conductivity coefficient after soaking for 4 h of the composite coating block were higher than 4.0 MPa and 0.225 W·m−1·K−1, respectively. The UFA-based superhydrophobic composite coating proposed in this study and applied onto foam concrete is simple and cheap, requires no precise instrument, and can be applied in a large area.

scholarly journals THE EFFECT OF MODIFIED ADDITIVES ON STRENGTH AND FROST RESISTANCE IN FIBROUS CONCRETE OF RIGID ROAD PAVEMENTS

2020 ◽  
pp. 68-74
Author(s):  
A.V. Mishutin ◽  
◽  
L. Chintea ◽  
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Portland Cement ◽  
Frost Resistance ◽  
Polypropylene Fiber ◽  
High Strength ◽  
Fibrous Concrete ◽  
Fiber Concrete ◽  
Mineral Additive ◽  
Compressive Strength Of Concrete

Abstract. The research is devoted to the development of compositions of modified fiber concrete of rigid road pavements with high strength and frost resistance through the use of metakaolin and a polycarboxylate type superplasticizer. The compressive strength, tensile strength under bending and frost resistance of concrete and fiber concrete of rigid road pavements were investigated according to the 4-factor optimal plan. In the experiment the amount of concrete components varied: Portland cement, polypropylene fibers, metakaolin, the polycarboxylate type additives Coral ExpertSuid-5. All mixtures had equal mobility P2 and their W/C depended on the composition of concrete. The use of polypropylene fiber and metakaolin necessitates an increase of W/C to maintain the mobility of the mixture. Increasing the amount of Coral ExpertSuid-5 additive in concrete to 0.9-1% allows to reduce significantly W/C of the mixture. Metakaolin as an active mineral additive increases the compressive strength and tensile strength of concrete. Rational in terms of increasing strength is the amount of metakaolin at the level of 20..22 kg/m3. With an increase in the amount of Coral ExpertSuid-5 additive to 0.9..1% due to a decrease of W/C, the compressive strength of concrete increases by 5..7 MPa, and the tensile strength increases by about 0.5 MPa. Due to the introduction of polypropylene fiber, the tensile strength of concrete in bending increases by 0.6..0.9 MPa. But dispersed reinforcement does not affect the compressive strength of concrete. The developed fiber concrete using a rational amount of modifiers, depending on the amount of Portland cement in the composition, has a compressive strength from 55 MPa to 70 MPa and tensile strength from 8 MPa to 9.5 MPa. The high strength of fiber-reinforced concretes allows their use in road pavements with the highest load. Frost resistance of concrete increases by 50 cycles or more when using fiber in an amount of 1.5-2 kg/m3. Due to the use of a rational amount of modifiers (0.8-1% Coral ExpertSuid-5 additive and 15-20 kg/m3 metakaolin), frost resistance of concrete and fiber concrete increases by 50-100 cycles. The developed modified fiber concretes of rigid road pavements depending on the amount of Portland cement in the composition have frost resistance from F350 to F450, which ensures their sufficient durability.

A novel aerogels/porous Si3N4 ceramics composite with high strength and improved thermal insulation property

2018 ◽  
Vol 44 (5) ◽  
pp. 5233-5237 ◽  
Author(s):  
Yongqiang Sun ◽  
Zhihao Zhao ◽  
Xiaolei Li ◽  
Hangyuan Zhao ◽  
Zhipeng Hu ◽  
...  
Keyword(s):  
Thermal Insulation ◽  
High Strength ◽  
Insulation Property ◽  
Porous Si3n4 ◽  
Thermal Insulation Property ◽  
Si3n4 Ceramics ◽  
Porous Si3n4 Ceramics

Bestimmung der Dauerhaftigkeit von Hochleistungsbeton mit Hilfe des CDF-Tests / Determination of the durability of high performance concrete by means of CDF-test

1999 ◽  
Vol 5 (1) ◽  
pp. 29-40
Author(s):  
R. Krumbach ◽  
U. Schmelter ◽  
K. Seyfarth
Keyword(s):  
Frost Resistance ◽  
High Strength Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Strength Concrete ◽  
Factors Influencing

Abstract Variable obsen>ations concerning frost resistance of high performance concrete have been made. The question arises which are the decisive factors influencing durability under the action of frost and de-icing salt. The proposed experiments are to be carried out in cooperation with F.A.- Finger - Institute of Bauhaus University Weimar. The aim of this study is to determine possible change of durability of high strength concrete, and to investigate the origin thereof. Measures to reduce the risk of reduced durability have to be found.

scholarly journals A Physical-Based Plane Stress Constitutive Model for High Strength AA7075 under Hot Forming Conditions

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 314
Author(s):  
Fulong Chen ◽  
Haitao Qu ◽  
Wei Wu ◽  
Jing-Hua Zheng ◽  
Shuguang Qu ◽  
...  
Keyword(s):  
Grain Size ◽  
Aluminum Alloy ◽  
Plane Stress ◽  
Metal Forming ◽  
Electron Backscatter Diffraction ◽  
High Strength ◽  
Material Model ◽  
Hot Forming ◽  
Industrial Processing ◽  
Average Grain Size

Physicallybased constitutive equations are increasingly used for finite element simulations of metal forming processes due to the robust capability of modelling of underlying microstructure evolutions. However, one of thelimitations of current models is the lack of practical validation using real microstructure data due to the difficulties in achieving statistically meaningful data at a sufficiently large microstructure scale. Particularly, dislocation density and grain size governing the hardening in sheet deformation are of vital importance and need to be precisely quantified. In this paper, a set of dislocation mechanics-based plane stress material model is constructed for hot forming aluminum alloy. This material model is applied to high strength 7075 aluminum alloy for the prediction of the flow behaviorsconditioned at 300–400 °C with various strain rates. Additionally, an electron backscatter diffraction (EBSD) technique was applied to examine the average grain size and geometrical necessary dislocation (GND) density evolutions, enabling both macro- and micro- characteristics to be successfully predicted. In addition, to simulate the experienced plane stress states in sheet metal forming, the calibrated model is further extended to a plane stress stateto accuratelypredict the forming limits under hot conditions.The comprehensively calibrated material model could be used for guidinga better selection of industrial processing parameters and designing process windows, taking into account both the formed shape as well as post formed microstructure and, hence, properties.

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