Effect of Polypropylene Fiber on Frost Resistance of Cemented Soil

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

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.250-253.822 ◽

2011 ◽

Vol 250-253 ◽

pp. 822-827

Author(s):

Jun Fang Huo ◽

Hui Yang ◽

Yong Li Hou ◽

Jian Jun Chu ◽

Wei Ling Li

Keyword(s):

Mass Loss ◽

Frost Resistance ◽

Steel Fiber ◽

Polypropylene Fiber ◽

Lightweight Aggregate ◽

Strength Loss ◽

Lightweight Aggregate Concrete ◽

Aggregate Concrete ◽

Resistance Durability ◽

The Impact

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.

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Concrete based on sulfur binder being modified with inorganic additives

MATEC Web of Conferences ◽

10.1051/matecconf/201821201013 ◽

2018 ◽

Vol 212 ◽

pp. 01013

Author(s):

Vadim Balabanov ◽

Victor Baryshok ◽

Nikita Epishkin

Keyword(s):

Frost Resistance ◽

Building Materials ◽

Physical And Mechanical Properties ◽

High Strength ◽

Strength Properties ◽

Climatic Conditions ◽

Freezing And Thawing ◽

Concrete Mixtures ◽

Irkutsk Region ◽

Water Saturated

The sharply continental climate of the Irkutsk region is characterized by wide temperature intervals throughout the year. The repeated cyclicity of freezing and thawing of building materials in the water-saturated state influences the change in technical characteristics and the durability of concrete products and structures. The concrete products’ features in such climatic conditions create the need for the production of concretes with improved indicators of physical and mechanical properties. The effect of modifying additives on the technological characteristics of sulfur concrete is established. The effect of all elements of sulfur concrete on its strength and frost resistance. The composition of sulfuric concrete is obtained, which meets all the requirements and also has high strength and increased frost resistance. Formulations with a certain ratio of structural sulfuric concrete mixtures were developed. As a result of the use of technical sulfur in the composition of concrete products, the problem of utilizing annually accumulating reserves of technical sulfur is partially solved. The strength properties of sulfuric concretes easily compete with high-quality brands of concrete, special types of concretes that have in their composition additives.

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Fire Performance of Columns Made of Normal and High Strength Concrete: A Comparative Analysis

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.711.564 ◽

2016 ◽

Vol 711 ◽

pp. 564-571 ◽

Cited By ~ 1

Author(s):

Thomas Gernay

Keyword(s):

Bearing Capacity ◽

High Strength Concrete ◽

Concrete Strength ◽

High Strength ◽

Strength Loss ◽

Fire Performance ◽

Load Bearing Capacity ◽

Load Bearing ◽

Strength Concrete ◽

The Impact

The use of high strength concrete (HSC) in multi-story buildings has become increasingly popular. Selection of HSC over normal strength concrete (NSC) allows for reducing the dimensions of the columns sections. However, this reduction has consequences on the structural performance in case of fire, as smaller cross sections lead to faster temperature increase in the section core. Besides, HSC experiences higher rates of strength loss with temperature and a higher susceptibility to spalling than NSC. The fire performance of a column can thus be affected by selecting HSC over NSC. This research performs a comparison of the fire performance of HSC and NSC columns, based on numerical simulations by finite element method. The thermal and structural analyses of the columns are conducted with the software SAFIR®. The variation of concrete strength with temperature for the different concrete classes is adopted from Eurocode. Different configurations are compared, including columns with the same load bearing capacity and columns with the same cross section. The relative loss of load bearing capacity during the fire is found to be more pronounced for HSC columns than for NSC columns. The impact on fire resistance rating is discussed. These results suggest that consideration of fire loading limits the opportunities for use of HSC, especially when the objective is to reduce the dimensions of the columns sections.

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

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1004-1005.1575 ◽

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.

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Experimental Study on Frost Resistance Durability of Lightweight Aggregate Concrete in Na2SO4 Solution

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.152-153.1565 ◽

2010 ◽

Vol 152-153 ◽

pp. 1565-1569

Author(s):

Jun Fang Huo ◽

Hui Yang ◽

Xiang Dong Shen ◽

Xiao Xia Ji ◽

Qi Cui

Keyword(s):

Frost Resistance ◽

Steel Fiber ◽

Polypropylene Fiber ◽

Lightweight Aggregate ◽

Strength Loss ◽

Interfacial Transition Zone ◽

Lightweight Aggregate Concrete ◽

Test Results ◽

Aggregate Concrete ◽

Resistance Durability

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.

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Frost Resistance Test Research on Hybrid Fiber Concrete Based on Range Analysis

The Open Construction and Building Technology Journal ◽

10.2174/1874836801509010292 ◽

2015 ◽

Vol 9 (1) ◽

pp. 292-297 ◽

Cited By ~ 2

Author(s):

Liu Faming ◽

Zhao Lisha ◽

Ma Jie

Keyword(s):

Compressive Strength ◽

Frost Resistance ◽

Loss Rate ◽

Steel Fiber ◽

Polypropylene Fiber ◽

Strength Loss ◽

Hybrid Fiber ◽

Freeze Thaw ◽

Thaw Cycle ◽

Fiber Concrete

The research of single doped fiber concrete is relatively mature. But the research about different varieties and different geometry shape of hybrid fiber concrete was very poor. Across the research in theory, hybrid fiber concrete can improve the balance of fiber three-dimensional distribution and coordinating role of aggregate and fiber, improve the efficiency of toughening crack resistance. In this paper, through the orthogonal experiment design method for hybrid fiber reinforced concrete, the mass and compressive strength loss rate after 50 times, 75 times, 100 times freeze-thaw cycle had been studied. Use range analysis quantified the influence level of various factors on the mechanical properties. It was analyzed the hybrid fiber influence on improving the efficiency of toughening crack resistance and frost resistance. It is concluded that adding the fiber can enhance the performance of concrete frost resistance. Long steel fiber have great influence on compressive strength loss rate of hybrid fiber concrete, such as the compressive strength loss rate was reached 65.47% after 75 times freeze-thaw cycle. Short steel fiber have certain influence on mass loss of concrete which were after less freeze-thaw cycles. The influence of polypropylene fiber on concrete frost resistance increases significantly, the effect can reach 36.78% after 50 times of freeze-thaw cycle. The optimal combination of the hybrid fiber concrete ultimately determined was A2B2C3 (simultaneously mixed with 50kg/m3 short steel fiber and long steel fiber as well as 0.9kg/m polypropylene fiber). The addition of steel fiber and polypropylene fiber are both beneficial to increase the internal air content of concrete, strengthening the frost resistance of concrete. However, with the increase of dosage, the internal porosity of concrete is gradually increasing, the density is reduced, and, as a result, the corresponding increase of the compressive strength loss rate is also improved.

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

Bulletin of Odessa State Academy of Civil Engennering and Architecture ◽

10.31650/2415-377x-2020-80-68-74 ◽

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.

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Influence of Polypropylene and Steel Fibers on the Performance and Crack Repair of Self-Compacting Concrete

Materials ◽

10.3390/ma14195506 ◽

2021 ◽

Vol 14 (19) ◽

pp. 5506

Author(s):

Mohammed A. Abed ◽

Jan Fořt ◽

Abdulkarim Naoulo ◽

Amr Essa

Keyword(s):

Polypropylene Fiber ◽

High Strength ◽

Fiber Content ◽

Injection Technique ◽

Self Compacting Concrete ◽

Simultaneous Application ◽

European Guidelines ◽

Strength And Stiffness ◽

Epoxy Resin Adhesive ◽

The Impact

The research reported in this paper aims to evaluate the epoxy injection technique used to strengthen fiber-reinforced self-compacting concrete (FRSCC) with high strength. This method is carried out on ruptured concrete specimens to assess the efficiency of the epoxy resin adhesive injection retrofitting technique for strength and stiffness. Five FRSCC mixes were designed and placed using different types (steel and polypropylene) and contents (0%, 0.25%, and 0.45% by volume) of fibers. The fresh and mechanical properties in addition to the microstructure of produced mixes were evaluated to assess the impact of fibers on the behavior of FRSCC. Results showed that the workability of FRSCC is reduced by increasing steel or polypropylene fiber content; however, the rheological characteristics of placed mixes satisfied the European Guidelines for Self-Compacting Concrete recommendation for fresh concrete. Also, splitting tensile, flexural, and shear strengths were enhanced by increasing fiber content. The simultaneous application of epoxy injection in FRSCC for repairing damaged concrete beams was shown to be highly effective.

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Does kraft hardwood and softwood pulp viscosity correlate to paper properties?

TAPPI Journal ◽

10.32964/tj15.10.643 ◽

2016 ◽

Vol 15 (10) ◽

pp. 643-651 ◽

Cited By ~ 1

Author(s):

ROBERT J. OGLESBY ◽

HUMPHREY J. MOYNIHAN ◽

RICARDO B. SANTOS ◽

ASHOK GHOSH ◽

PETER W. HART

Keyword(s):

Physical Properties ◽

Strength Loss ◽

Strength Properties ◽

Clear Correlation ◽

Paper Properties ◽

Physical Strength ◽

Pulp Viscosity ◽

Softwood Pulp ◽

The Impact ◽

A Predictive Model of the Impact of the Skidding System on Forest Soil in Severe Climatic Conditions

Lesnoy Zhurnal (Forestry Journal) ◽

10.37482/0536-1036-2020-5-131-144 ◽

2020 ◽

pp. 131-144

Author(s):

S.E. Rudov ◽

◽

V.Ya. Shapiro ◽

O.I. Grigoreva ◽

I.V. Grigorev ◽

...

Keyword(s):

Forest Soil ◽

Warm Season ◽

Climatic Conditions ◽

Soil Freezing ◽

Class Iii ◽

Freezing And Thawing ◽

Metal Structures ◽

Rapid Adjustment ◽

Soil Freezing And Thawing ◽

The Impact

In the Russian Federation logging operations are traditionally carried out in winter. This is due to the predominance of areas with swamped and water-logged (class III and IV) soils in the forest fund, where work of forestry equipment is difficult, and sometimes impossible in the warm season. The work of logging companies in the forests of the cryolithozone, characterized by a sharply continental climate, with severe frosts in winter, is hampered by the fact that forest machines are not recommended to operate at temperatures below –40 °C due to the high probability of breaking of metal structures and hydraulic system. At the same time, in the warm season, most of the cutting areas on cryosolic soils become difficult to pass for heavy forest machines. It turns out that the convenient period for logging in the forests of the cryolithozone is quite small. This results in the need of work in the so-called off-season period, when the air temperature becomes positive, and the thawing processes of the soil top layer begin. The same applies to the logging companies not operating in the conditions of cryosolic soils, for instance, in the Leningrad, Novgorod, Pskov, Vologda regions, etc. The observed climate warming has led to a significant reduction in the sustained period of winter logging. Frequent temperature transitions around 0 °C in winter, autumn and spring necessitate to work during the off-season too, while cutting areas thaw. In bad seasonal and climatic conditions, which primarily include off-season periods in general and permafrost in particular, it is very difficult to take into account in mathematical models features of soil freezing and thawing and their effect on the destruction nature. The article shows that the development of long-term predictive models of indicators of cyclic interaction between the skidding system and forest soil in adverse climatic conditions of off-season logging operations in order to improve their reliability requires rapid adjustment of the calculated parameters based on the actual experimental data at a given step of the cycles.

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