Rubber Powder Research Articles

Research on the factors affecting the compressive strength of rubber powder modified cement-stabilized crushed stone based on orthogonal experiments

Based on an orthogonal experimental design, this study introduces rubber powder particle size alongside rubber powder content, aggregate gradation, and cement content as factors. A total of 16 mix proportions were formulated. For each mixture, compaction tests and unconfined compressive strength (UCS) tests were conducted. Using Statistical Product and Service Solutions (SPSS) software, a multifactor variance analysis was performed to determine the influence levels of the four factors on maximum dry density and compressive strength. The optimal mix proportion was selected based on compressive strength. The results indicate that aggregate gradation and rubber powder content significantly affect the maximum dry density of the mixture, with aggregate gradation having the greatest impact. Rubber powder content has the most substantial effect on compressive strength, while rubber particle size has the least influence. The optimal formulation is 7% cement content, 30-mesh rubber powder, 0.5% rubber powder content, and a skeletal dense gradation close to the median.

Incorporating geranium plant waste into ultra-high performance concrete prepared with crumb rubber as fine aggregate in the presence of polypropylene fibers

Abstract This research examines the efficiency of ultra-high-performance concrete (UHPC) when utilizing geranium plant (GP) ash, which is subjected to different curing temperatures ranging from 300 to 900°C for 3 h of burning time. The GP ash is used as a replacement for cement in varying amounts (10, 20, 30, 40, and 50 wt%). Crumb rubber powder is utilized as a substitute for fine aggregate. Polypropylene fibers have been used to improve concrete performance. The performance of UHPC is evaluated by assessing its mechanical qualities, such as flexural strength, splitting tensile strength, and compressive strength. The sorptivity test is also evaluated as a component of it. Scanning electron microscopy is used to analyze UHPC after exposure to temperatures as high as 900°C. The findings demonstrated a notable enhancement in the mechanical characteristics of all mixtures. The most favorable mixtures were achieved with proportions of 50, 40, 40, and 20% for mixtures including GP waste incinerated at temperatures ranging from 300 to 900°C. Furthermore, the optimal outcome is achieved when 40% substitution is performed at a temperature of 700°C, resulting in notable enhancements of 14% in compressive strength, 30% in flexural strength, and 17% splitting tensile strength, respectively. At a high temperature of 700°C, the decrease in strength increased to approximately 37–40% as a result of the initial removal of carbon dioxide from calcite at temperatures ranging from 600 to 900°C and reached 56% at 900°C. Great resistance to sorptivity, as well as a dense and compact microstructure with a high content of calcium and silicon, was obtained.

Thermal conductivity of fiber-reinforced foam concrete filled with crumb rubber powders

Thermal conductivity of fiber-reinforced foam concrete filled with crumb rubber powders

Investigation of the aggregation behavior of rubber asphalt components induced by short-term Aging: A perspective from molecular dynamic simulations and microscopic tests

The distribution characteristics of different rubber asphalt components remain a subject of debate, particularly under the influence of asphalt short-term aging. This paper leverages the visualization advantages of molecular dynamics (MD) simulation and integrates them with microscopic testing methods to observe morphological variations and property changes in the aggregation of different components induced by short-term aging. Short-term aging of rubber asphalt is simulated using a thin-film oven test (TFOT). By conducting Fluorescence microscope (FM) and scanning electron microscope (SEM) tests, the aggregation behavior of components under changes in fluorescence phase and microstructure before and after short-term aging is revealed. MD simulation is employed to analyze the degree of aggregation between different components before and after short-term aging. SEM test results indicate that the structure becomes looser and forms distinct pits as the rubber asphalt ages. FM test results reveal that the particle size of rubber powder particles in aged rubber asphalt decreases and aggregates gradually. Concurrently, the asphalt phase in rubber asphalt becomes more uniform after aging. MD simulation results demonstrate significant aggregation between asphaltene-asphaltene molecules and asphaltene-rubber powder molecules in aged rubber asphalt. A higher degree of asphaltene aggregation leads to reduce asphalt penetration and increase softening point and viscosity. Furthermore, rubber powder molecular chains can inhibit “π-π stacking,” and “offset π-π stacking” of the asphaltene molecules. Therefore, the accumulation effect in aged rubber asphalt is mitigated compared with aged base asphalt. The research outcomes provided a foundation for further studies on the aging and rejuvenation of rubber asphalt.

Study on the Performance of Modified Qingchuan Rock/Rubber Asphalt

This paper developed a new environmentally friendly composite modified asphalt material and studied the composite modification of Qingchuan rock asphalt (QRA) and waste tire rubber powder (RP) was studied in this paper. QRA/RP composite modified asphalt was prepared by adding these two materials as modifiers into matrix asphalt and compared with matrix asphalt and QRA modified asphalt. The basic properties of asphalt before and after aging were evaluated by the rotating thin film oven test. The high-temperature performance and permanent deformation resistance at different temperatures and frequencies were analyzed by the dynamic shear rheological test. The bending creep stiffness test was used to evaluate the low-temperature performance. In addition, the microstructure and modification mechanism of composite-modified asphalt were analyzed by scanning electron microscopy and infrared spectroscopy. The results show that QRA-modified asphalt is superior to matrix asphalt in terms of mass loss, viscosity ratio, and residual penetration, while QRA/RP composite-modified asphalt is further improved on this basis, QRA/RP composite modified asphalt can effectively improve the high and low temperature performance of asphalt.. Although the addition of RP is mainly based on physical modification, it also causes weak chemical reactions and enhances the adhesion of asphalt. The interaction between Qingchuan Rock asphalt and rubber powder significantly improves the overall stability of asphalt structure.

Pengaruh Waktu Iradiasi Ultrasonik dengan Aktivasi Kalium Hidroksida terhadap Sifat Fisis Karbon Aktif dari Serbuk Karet End Life Tire

Processing End Life Tire (ELT) rubber powder into activated carbon is an alternative for handling tire waste. One way to improve physical properties such as proximate characteristics, surface area and pore diameter of activated carbon is through chemical activation assisted by ultrasonic irradiation. This research aims to determine the effect of ultrasonic irradiation time with potassium hydroxide (KOH) activation on the quality of ELT rubber activated carbon. Activated carbon was synthesized and activated using 30% KOH at various ultrasonic irradiation times, namely 0 minutes, 15 minutes, 30 minutes, 45 minutes and 60 minutes. Based on the characterization results, activated carbon with an ultrasonic irradiation time of 30 minutes is the active carbon that has the most superior properties. The proximate characteristics of activated carbon meet the active carbon quality requirements of SNI 06–3730–1995 and have the highest surface area, namely 401.11 m2/g and pore diameter of 2.1652 nm, which is included in the mesoporous structure category so that it has the potential to be applied as an adsorbent for heavy metals from contaminated fluid.

Crack-healing of cost-effective engineered cementitious composites reinforced by recycled selvage fiber

This paper presents the first experimental investigation of the crack-healing behavior of recycled selvage fiber-reinforced engineered cementitious composites (RSF-ECCs). Fly ash (FA), ground granulated blast-furnace slag (GGBS), and crumb rubber powder were utilized to fabricate greener ECCs. RSF was used as main reinforcement; it contains polyethylene (PE), glass (GS), and PET fibers. For overall mechanical properties, RSF-ECC incorporating GGBS (ECC-S-RSF) obtained a compressive strength of over 80 MPa and a tensile strain capacity of over 10%, values that are unprecedented in other recycled fiber-reinforced ECCs. Furthermore, the ECC-S-RSF showed the best cost efficiency among representative recycled and PE fiber-reinforced high-performance ECCs. In terms of the crack-healing performance, test results indicated that RSF-ECCs had excellent healing capacity in closing crack openings, and GGBS had a greater contribution to crack-healing than FA did. However, the stiffness and tensile restorations of RSF-ECCs were relatively modest compared to those of conventional ECCs. Calcium carbonate and C-S-H gel were dominant healing materials of RSF-ECCs.

A different approach for green concrete production: Determination of the effect of e-waste and waste rubber powder on durability properties of concrete

A different approach for green concrete production: Determination of the effect of e-waste and waste rubber powder on durability properties of concrete

Development of sustainable HPC using rubber powder and waste wire: carbon footprint analysis, mechanical and microstructural properties

This research advances the development of eco-friendly high-performance concrete (HPC) by integrating tire rubber powder and waste wire, focusing on both enhanced mechanical properties and reduced environmental impact. Substituting up to 40% of silica sand with rubber powder helps maintain the compressive strength necessary for high-strength concrete applications. The addition of waste wire is designed to improve ductility. A comprehensive evaluation includes mechanical and microstructural analyses, such as compressive, splitting tensile, and flexural strength assessments, in addition to Scanning Electron Microscopy (SEM) and Differential Thermal Analysis (DTA). Environmental implications are assessed by measuring the embodied carbon footprint. Findings indicate that the absence of rubber powder allows for a compressive strength peak of 95 MPa, while 50% rubber content leads to a decrease to 25 MPa, establishing a 40% rubber threshold for optimal strength. Conversely, 3% waste wire reinforcement enhances the strength to 106 MPa. Microstructural investigations reveal that increased rubber content adversely affects compressive strength by weakening the cement matrix, and reducing calcium-silicate-hydrate (C-S-H) formation. Significantly, the study reveals that replacing silica sand with rubber powder, along with waste wire reinforcement, substantially reduces the carbon footprint of the material, contributing to more sustainable construction methodologies.

Evaluation on the Crack Resistance of Cement-Stabilized Macadam Mixture with Crack-Resistant Interlocking Gap Gradation and Rubber Powder

Evaluation on the Crack Resistance of Cement-Stabilized Macadam Mixture with Crack-Resistant Interlocking Gap Gradation and Rubber Powder

Tensile behavior of rubberized high strength-high ductile concrete under elevated temperature

High Ductility Concrete (HDC) exhibits unique mechanical properties at ambient temperatures, but its behavior at elevated temperatures is less understood. This study examines the mechanical behavior of Rubber-modified High-Strength High-Ductility Concrete (R-HSHDC) across various temperatures (25, 75, 100, and 150°C) and rubber replacement ratios. The study explores R-HSHDC’s microstructure, failure modes, strength, and deformability, focusing on its pseudo-strain hardening behavior. Results indicate that below 100°C, R-HSHDC displays typical HDC characteristics, including multiple cracking and high tensile deformation. As temperature increases, both initial cracking strength and tensile strength decrease, while crack control and energy absorption are maintained. Moderate rubber powder reduces initial cracking strength and enhances tensile deformability. When using R-HSHDC as a structural material, temperature effects must be considered. At higher temperatures, R-HSHDC is more suitable for crack control and energy dissipation. This research improves understanding of R-HSHDC's behavior at different temperatures, aiding in structural and functional design for high-temperature environments.

Study on mechanical properties and failure mechanism of epoxy resin/aluminum foam/rubber powder three‐phase composites

AbstractIn this paper, three‐phase composites were made by combining N220 carbon black rubber powder with open‐cell aluminum foam and epoxy resin with mass fractions of 3 %, 5 %, and 7 %, respectively. The mechanical and energy absorption properties of three groups of epoxy resin/rubber powder/aluminum foam three‐phase composites with added aluminum foam and different mass fractions of N220 carbon black rubber powder were analyzed during quasi‐static compression at a compression rate of 2 mm/minute. The mechanical parameters in the quasi‐static compression experiments were compared with those of the two‐phase composites of epoxy resin/rubber powder with no added aluminum foam. Finally, the micro‐morphology of the composites after quasi‐static compression damage was observed by scanning electron microscopy. The results show that the collapse deformation of aluminum foam during compression affects the stability of the epoxy resin/rubber powder composite matrix and reduces the toughness of the epoxy resin/rubber powder composite matrix.

Modification of the Crumb Rubber Asphalt by Eucommia Ulmoides Gum under a High-Temperature Mixing Process

The crumb rubber (CR) asphalt has some defects of high viscosity and poor storage stability, which brings great challenge to the high-quality construction of the CR asphalt pavement. To improve the interaction between the CR and base binder, the Eucommia ulmoides gum (EUG) with double-bond structure similar to trans-polyoctenamer rubber (TOR) was used to modify the CR asphalt. However, the original EUG double bond is basically inactive at room temperature and cannot form the effect of TOR. Open double bonds of EUG with asphalt and rubber powder form a network structure similar to TOR-modified rubber asphalt by high-temperature mixing with EUG in a torque rheometer. The effects of modified CR on rubber asphalt were analyzed by macro- and micro-experiments such as rotational viscosity tests, segregation tests, FTIR tests, and PG tests. It was found that the high-temperature mixing process works in both physical and chemical ways to mix the CR and EUG into an inseparable substance. The modified CR has higher chemical activity after desulfurization and degradation, which allows it to form a more effective chemical connection with asphalt. EUG can build a stable spatial crosslinking structure in CR asphalt due to the sulfurization reaction, which significantly improves the construction workability and system stability of the CR asphalt.

Improving the scour-resistance performance of for offshore wind turbines: Experimental and computational fluid dynamics studies on macro and micro characteristics

To enhance the resistance to local scour around offshore wind turbine monopiles, 15 mixtures were designed based on Response Surface Methodology (RSM). Cement content, sodium silicate content, and rubber powder content were selected as independent variables. After determining their flowability, the compressive strength and shear strength were measured after curing in pure water and artificial seawater for 3 days, 7 days, 14 days, and 28 days. Experimental results indicate significant improvement in the mechanical properties of the modified soil, including increased Unconfined Compressive Strength (UCS), internal friction angle, and cohesion. The optimal mix ratio is identified as CSR40–10–15, consisting of 40 % cement, 10 % sodium silicate, and 15 % rubber powder. The strength variation mechanism is elucidated from both macroscopic and microscopic perspectives. Finally, numerical simulations using Computational Fluid Dynamics (CFD) software validate the scour resistance performance based on the optimal mix ratio of flowable solidified soil, offering a new approach for local scour protection around offshore wind turbine monopile.

Investigating the properties of a novel organic composite warm mix additive on SBS modified asphalt binder

This study investigated the effects of new organic composite warm mix additive on the performance and microstructure of SBS modified asphalt binder. Acmp, as an organic composite warm mix additive, was used to prepare warm mix SBS modified asphalt binders with different contents, and compared and analyzed with Sasobit and Evotherm warm mix additives. The rheological properties of asphalt binders were evaluated by rotational viscometer, dynamic shear rheometer and bending beam rheometer. The effects of the warm mix additives on chemical composition and microstructure of binders were analyzed by fourier transform infrared spectroscopy, thermogravimetric analysis and fluorescence microscope. The results showed that, Acmp had significant viscosity reducing effect, and 6 % Acmp reduced the rotational viscosity of binder by approximately 50 %. Acmp warm mix modified asphalt binder exhibited better low temperature performance compared to Sasobit and Evotherm, but Acmp had negative impact on the high temperature performance. Acmp was mainly composed of light components produced by the cracking of rubber powder and plastic powder, which were mainly short chain alkanes and did not affect the distribution of SBS in binder. These light components were well soluble in asphalt binder to improve its fluidity and were the main components that affected the performance of binders and achieved warm mix effects. Considering the performance of asphalt binder and mixture, Acmp is more suitable for pavements in cold regions, with a recommended dosage of 5 % of asphalt mass. The findings validate the effectiveness of organic composite warm mix additives and contribute to the exploration of more efficient new warm mix technologies.

Use of Waste Tyre Rubber Powder and Waste Plastic in Bituminous Road Construction

Use of Waste Tyre Rubber Powder and Waste Plastic in Bituminous Road Construction

Mechanical Properties of Cement Concrete with Waste Rubber Powder

To investigate the mechanical properties of cement concrete incorporating waste rubber powder, the response surface methodology was employed. The Box–Behnken central composite design was applied to analyze the three primary factors influencing the road performance of cement concrete containing waste rubber powder: the water–cement ratio, sand ratio, and waste rubber powder content. The study determined the impact of these factors on the flexural strength of waste rubber powder cement concrete at both 7 and 28 days. Additionally, the effects of the water–cement ratio, sand ratio, and waste rubber powder content on the performance of cement concrete were analyzed. To investigate the impact of waste rubber powder on cement concrete, various mechanical property tests were conducted, including compressive, flexural, dynamic elastic modulus, and impact performance tests. Furthermore, the study explored the influence of waste rubber powder on the noise reduction capacity of cement concrete using both the rubber ball impact method and ultrasonic method. Lastly, the durability of cement concrete with added rubber powder was assessed through shrinkage tests, frost resistance tests, and chloride ion penetration tests.

Study on self-healing performance of microcracks in SBS/waste rubber powder composite-modified asphalt based on molecular dynamics simulation

The internal microcracks in asphalt materials can heal spontaneously under suitable conditions, and understanding the characteristics of the self-healing behavior of asphalt materials is crucial for evaluating the fatigue life of asphalt pavements. In this paper, a molecular model of modified asphalt microcracks was created by introducing modifier molecules into the virgin asphalt model, and the self-healing process of the asphalt microcrack model under different healing conditions was investigated, which revealed the effects of modifier materials and healing temperatures on the healing performance of asphalt. The results show that the effect of healing temperature on asphalt healing performance is more significant than the modifier material, the relative concentration of molecules at the microcrack healing and the healing temperature is positively correlated; asphalt material healing free volume fraction with the increase in healing temperature gradually increases, the incorporation of modifiers can reduce the free volume fraction growth caused by high-temperature healing, improve the healing stability of modified asphalt. The asphalt ductility specimen crack healing test shows that when the healing temperature exceeds 45 ℃, there is a decreased increase in self-healing rate; taking into account the high-temperature healing is easy to make the asphalt material produce permanent deformation, this paper determines the optimal healing temperature in the vicinity of 48 ℃. The research results have certain reference and application values for asphalt pavement damage repair.

Fracture behavior of environmentally friendly high-strength concrete using recycled rubber powder and steel fibers: Experiment and modeling

Ultra-high-performance concrete (UHPC) is becoming increasingly popular for its exceptional mechanical properties but suffers from high cost and limited ductility. To overcome these limitations, this study explores the development of cost-effective and ductile Environmentally friendly High-strength Concrete (E-HSC) by incorporating recycled steel fiber (RSF) and rubber powder into UHPC. Fracture properties and crack propagation behavior were examined through three-point bending fracture tests on notched beams with varying rubber powder (0 %, 5 %, 20 %, 35 % and 50 %) and recycled steel fiber (1 %, 2 % and 3 %) content. Digital Image Correlation method was Used to Measure Crack mouth opening displacement and Fracture process zone in the Fracture Process of E-HSC of the E-HSC were analyzed using the digital image correlation method. Results revealed that E-HSC with 5 % rubber powder exhibited superior fracture energy and double-K fracture toughness. The use of rubber powder and RSF enhances the ductility of concrete, with the characteristic length consistently increasing as the content of rubber powder and RSF increases. Additionally, a softening constitutive model was proposed to evaluate the fracture performance of E-HSC based on rubber powder and recycled steel fiber content. This research provides experimental data and theoretical insights for developing resilient E-HSC suitable for applications in significant structures.

Design of sustainable bituminous concrete pavement with cement–treated granular layers constructed on stabilized subgrade

Purpose Designing a sustainable bituminous concrete with long-term performance is a challenging problem. In addition, strength of the subgrade has a crucial impact on pavement design. This paper aims to concentrate on subgrade soil stabilization with granite dust powder (GDP) and crumb rubber powder (CRP) to improve the engineering properties of the soil. Further design of bituminous concrete pavement with cement-treated layers in base and subbase course layers was carried out with life cycle cost analysis and life cycle assessment for 1 km of a four-lane national highway. Design/methodology/approach Subgrade soil stabilized with GDP and CRP is characterized as per Indian Standards (IS)-2720 to determine the optimum dosage. Further, the mechanistic-empirical pavement design was carried out using Indian Road Congress-37 (2018), analyzed using IITPAVE software and validated with ANSYS software. The life cycle cost analysis is carried out using the net present value method, and the life cycle assessment is performed according to the cradle-to-grave approach. Findings A soil mix comprising 10% GDP and 2.5% CRP yielded a soaked California bearing ratio value of 6.58%. In addition, the design of bituminous concrete pavement with cement-treated granular layers showed a 26.9% reduction in life cycle cost and 59.4% reduction in total carbon footprint per kilometer compared to the pavement with traditional aggregate layers. Originality/value The research on subgrade stabilization with sustainable materials like GDP and CRP incorporating mechanistic empirical pavement design, life cycle cost analysis and life cycle assessment is limited. Overall, the study recommends the use of GDP and CRP to stabilize soil for subgrade application and incorporate cement-treated granular layers, which offer economic and environmental benefits compared to traditional pavement construction.