• Journal of the Korean Geotechnical Society
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• v.28 no.9
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• pp.47-55
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• 2012

This paper investigates the shear properties of crumb rubber-bottom ash mixture reinforced by waste fishing net (WFN). Mixtures used in this experiment consist of crumb rubber and bottom ash (2mm~10mm) with the same weight ratio. In this study several series of direct shear tests were carried out on the five different specimens : unreinforced mixture, reinforced mixtures with 1 or 2 single-layered WFN, reinforced mixtures with 1 or 2 double-layered WFN. The experimental results indicated that the shear properties of reinforced crumb rubber-bottom ash mixture were strongly influenced by reinforcing layer of WFN. It was found that the shear strength and internal friction angle of the mixtures increased with an increase in reinforcing layer of WFN due to interlocking effect and friction between mixture and WFN.

• Structural Engineering and Mechanics
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• v.85 no.2
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• pp.275-287
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• 2023

The use of environmental-friendly building materials is becoming increasingly popular worldwide. Compared to the normal concrete, rubber-based concrete is considered more durable, environmentally friendly, socially and economically viable. In this investigation, M20 grade concrete was designed and the fine aggregates were replaced with crumb rubber of two different micron sizes (0.221 mm and 0.350 mm). Fly ash (FA) and silica fume (SF) replaces the binder as supplementary cementitious materials at a rate of 0, 5, 10, 15, and 20% by weight. The mechanical properties of concrete including compressive strength, tensile, and flexural strength were determined. The polynomial work expectation validates the response surface approach (RSM) concept for optimizing SF and FA substitution. The maximum compressive strength (22.53 MPa) can be observed for the concrete containing 10% crumb rubber, 15% fly ash and 15% silica fume. The reduced unit weight of the rubberized concrete may be attributed to the lower specific gravity of the rubber particles. Two-way ANOVA with a significance criterion of less than 0.001 has been utilized with modest residual error from the lack of fit and the pure error. The predictive model accurately forecasts the variable-response relationship. Since, the crumb rubber is obtained from wasted tires incorporating FA and SF as a cementitious ingredient, it helps to significantly improve mechanical properties of concrete and reduce environmental degradation.

• Journal of Environmental Science International
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• v.10 no.4
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• pp.311-314
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• 2001

The asphalt mixture with CRM(Crumb Rubber Modifier) is known to show a better performance in resisting thermal cracking, fatigue cracking and rutting compared with the conventional mixture. The laboratory tests on the physical characteristics of indirect tensile strength, density, flow and Marshall value of the CRM asphalt were conducted. The test results show that CRM asphalt has better physical characteristics than that of conventional asphalts. And the analysis on the noise reduction effect, penetration capacity from the field test on the national road in Haksan of Chungbuk, and recycling of tire waste were conducted. From this study, the results show that 1% CRM asphalt has higher the noise reduction effect and penetration capacity that those of conventional asphalts. And, optimal contents of crumb rubber modifier in the asphalt binder is one percent. In this case, crumb rubber modifier were used 10 kg to make the asphalt binder of one cubic meter. So it was named as Eco-asphalt.

• Steel and Composite Structures
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• v.41 no.5
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• pp.649-661
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• 2021

This paper presents experimental and analytical studies to understand the behavior of crumb rubber concrete (CRC)-filled fiber reinforced polymer (FRP) and steel tube double skin column (DSC) and beam (DSB) members under cyclic loading. The main test variable was the percentage of rubber which ranged from 0 to 40%. For column members, different heights corresponding to different aspect ratios were examined to understand the to understand the effect of DSCs' slenderness on the cyclic response of the columns. the. The behavior of the specimens in terms of failure mode, strain development, energy dissipation, load-displacement response were presented and compared. The ability of the current provisions of the Australian codes to predict the capacity of such double skin members was also evaluated based on the test results. This study concluded that the reduction in the concrete strength was more severe at the material level compared to structural level. Also, as the load changed from axial compression in columns to pure moment in beams the negative effect of rubber percentage on the strength became less significant.

• Polymer Science and Technology
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• v.8 no.6
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• pp.754-760
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• 1997

• International Journal of Highway Engineering
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• v.18 no.6
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• pp.41-50
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• 2016

OBJECTIVES : In this study, microstructural components of crumb rubber modified asphalt (CRMA) binder were investigated using environmental scanning electron microscope (ESEM). To clearly understand the elemental composition of the CRMA binder, energy dispersive X-ray spectroscopy (EDX) was employed on the ESEM samples. METHODS : CRMA binders were produced using open blade mixers at $177^{\circ}C$ for 30 min. The binders were artificially aged through a series of accelerated aging processes. Sample preparation was done by making a mold shape on the glass slide. Thereafter, the morphology of the CRMA binder was observed using the ESEM coupled with the EDX. RESULTS : The images captured from the ESEM indicate that the unaged CRMA binder appears to have a single-phase continuous nonuniform structure after the addition of crumb rubber particles, whereas the artificially aged CRMA binder was observed to have two different phases. ESEM coupled with EDX shows detailed internal structure of the modified binders compared to other technologies (i.e., optical microscopy, atomic force microscopy, and conventional scanning electron microscope). CONCLUSIONS : The captured images resemble the internal structures such as the viscous properties of the unaged CRMA binder and the interaction between the rubber particles and the base binder at aged condition. ESEM is a powerful instrument and with the introduction of EDX, it provided more details of the network microstructure of the asphalt binder. ESEM coupled with EDX is recommended for use in future investigation of microstructure of asphalt binders.

• International Journal of Highway Engineering
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• v.10 no.3
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• pp.239-246
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• 2008

In this study, the influence of reaction temperatures, mixing time and flexible modifier for crumb rubber modified asphalt(CRMA) as processing conditions were investigated. The temperature susceptibility and adhesion properties of neat and modified asphalts at low temperature measured using the penetration and tensile adhesion test. It was found that processing temperatures and flexible modifier were important factors for tensile adhesion strength and toughness energy at low temperature. The CRMA in the higher processing temperature and flexible modifier exhibited improved tensile adhesion properties which indicated the flexible structure of neat and modified asphalt binder. In general, the improvements of the physical properties in the CRMAs were due to the improvements of miscibility between CR and asphalt binder. It was found that the adhesion properties of the flexible agent modified CRMA were higher than CRMA were related to the flexible agent tend to penetrate into CR particles and asphalt binder.

• Magazine of RCR
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• v.10 no.4
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• pp.50-56
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• 2015

• International Journal of Highway Engineering
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• v.2 no.1
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• pp.123-133
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• 2000

The asphalt mixture with CRM(Crumb Rubber Modifier) is known to show a better performance in resisting thermal cracking, fatigue cracking, and rutting compared with the conventional mixture. In this research, the lab tests on the physical and the mechanical characteristics of the domestic crumb rubber modified asphalt binder and conventional asphalts (AP-3, AP-5) were conducted. The physical test results show that CRM asphalt has better physical characteristics than that of conventional asphalts. The dynamic shear rheometer test results in high temperature show that CRM asphalt has higher complex shear modulus and aging resistance than those of conventional asphalts. And, the bending beam rheometer in low temperature test results show that CRM asphalt has higher resistance to thermal cracking than that of conventional asphalts.

• Advances in concrete construction
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• v.11 no.5
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• pp.409-417
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• 2021

The incorporation of non-biodegradable tyre waste in cement-based material has gained more interest towards sustainable construction these days. Crumb rubber (CR) from waste tyre is an alternative for sand replacement in low strength applications. Many researchers have studied CR cement-based materials produced by normal mixing (NM) method and reported a significant decrease in compressive strength due to CR. To compensate this strength loss, this research aims to study the innovative incorporation of CR in cement composite via the preplaced mixing (PM) method. In this investigation, cement composite was produced with NM and PM methods by replacing sand with 0%, 50%, and 100% CR by volume. The test results showed no significant difference in terms of densities of cement composite prepared with both mixing methods. However, cement composite prepared with PM method had lower strength reduction (about 10%) and lowered drying shrinkage (about 20%). In addition, the sound absorption coefficient and noise reduction coefficient of CR cement composite prepared by PM method were in similar range as those prepared with NM method. Overall, the results demonstrate that the PM method is promising, and the maximum replacement level of 50% is recommended for CR in the cement composite.