Crumb Rubber Research Articles

Evaluation of asphalt modified with bio-oil and high rubber content: Low temperature and short mixing time production condition

High rubber content modified asphalt needed high production temperatures due to the high viscosity, but the viscosity and production temperature could be decreased by adding bio-oil. Producing rubber and bio-oil modified asphalt (BRMA) with good performance under low temperatures and short mixing time had significant environmental contributions. Therefore, this study prepared BRMA with crumb rubber content of 20 % and bio-oil content of 5 %, 10 %, and 15 % under the low-temperature (160 °C) and short-time (30 min) shear conditions. The rheological characteristics of BRMA were evaluated by conventional and rheological property tests. The interaction mechanism among rubber, bio-oil, and asphalt was assessed with the Fourier Transform Infrared test (FTIR) and Fluorescence Microscope test (FM). The addition of bio-oil had a significant impact on reducing the increase in asphalt viscosity that was typically caused by rubber modification. The high-temperature performance, elastic performance, and low-temperature performance of BRMA were significantly improved. The PG grade of neat asphalt was PG 64–22, 20 %R + 5 %Bio was PG 70–34, 20 %R + 10 %Bio was PG 70–34, and 20 %R + 15 %Bio was PG 64–40. Under the condition of low mixing temperature and short reaction time, the FTIR test found that no new absorption peak appeared, and the bio-oil, rubber, and asphalt were mainly physical mixing. Through the FM test, it was found that rubber reacted with asphalt at different degrees, and some crumb rubber that did not fully react ensured that asphalt still had good elastic properties and deformation resistance at high temperatures. The research provided theoretical guidance for similar application scenarios, such as dry process rubber modified asphalt.

Influence of crosslinking effect on chemical and rheological properties of aged liquid bio-rubber composite SBS modified asphalt

The influence of the cross-linking effect between a liquid bio-rubber (LBR), a desulphurised crumb rubber formed via pyrolysis in bio-oil, SBS, a cross-linker, and asphalt on the chemical and rheological properties of aged LBR/SBS composite modified asphalt (LBR/SBSMA) was studied. Four types of modified asphalts were prepared by adding LBR, LBR+sulphur, LBR+SBS and LBR+SBS+sulphur to simulate cross-linking. FTIR and GPC were used to obtain oxidation, aromatisation and polymer degradation indexes and molecular weight. DSR and BBR were used to acquire rheological indexes. Sulphur was the key factor in achieving cross-linking, which promoted phase morphology stability, enhanced oxidation and aromatisation resistance and restrained polymer degradation. LBR could prevent the variation of |G*| and the change of δ in high frequency after ageing. The low-temperature performance of aged LBR asphalt was satisfactory. The cross-linking effect retained superior ageing resistance despite a slight impairment of low-temperature continuous grading temperature, producing a sustainable and high-performance modified asphalt.

Exploring potential of Marshall-RT as simple performance test to evaluate rutting resistance of asphalt mixtures

ABSTRACT This study explored a new simple monotonic Marshall rutting test (Marshall-RT) to evaluate the rutting resistance of asphalt mixtures. The Marshall-RT test setup combines the Marshall fixture (at the bottom) and the IDT fixture (at the top). The rutting resistance of asphalt mixtures was evaluated using peak load (Pmax) and work done for the deformation damage obtained from the load-displacement curve. Nine plant-produced asphalt mixtures having different types of binders (unmodified, crumb rubber modified binder (CRMB)), and polymer modified binder (PMB)) and gradations having different nominal maximum aggregate sizes (NMAS) were evaluated. The Marshall-RT test parameters (i.e. Pmax and W P m a x ) have shown a strong correlation with fundamental (i.e. Flow Number (FN)), simulative (i.e. Hamburg wheel tracking test (HWTT)), and simple monotonic (i.e. Ideal rutting test (IDEAL-RT)) rutting tests. Moreover, the Marshall-RT test has shown good repeatability, the highest differentiation potential, and consistent ranking with other rutting tests. Furthermore, for high traffic levels (i.e. 100 MSA (Million Standard Axle)), at 50°C preliminary minimum threshold criteria were proposed for Marshall-RT (Pmax and W P m a x ), and IDEAL-RT (RTIndex) as 5 kN, 14 kN-mm, and 90, respectively, to avoid premature rutting failure. Thus, the newly developed monotonic Marshall-RT test can also be used as a surrogate simple performance test to estimate the rutting potential of asphalt mixtures during the mix design and plant production phases as quality control (QC)/quality assurance (QA).

Evaluation of Rutting, Fatigue, and Moisture Resistance of Low-Energy Asphalt Mixtures Modified by Crumb Rubber

Low-energy asphalt (LEA) mixture, as an alternative to hot mix asphalt (HMA) due to its lower mixing temperature, has advantages such as reducing energy consumption and environmental pollutants. LEA has poor performance characteristics due to the presence of water in its manufacturing process and low mixing temperature. All the studies about LEA have been focused only on investigating the performance of this asphalt mixture, and the effect of additives in its modification is one of the research gaps in this field. Therefore, the use of crumb rubber (CR) and determining its optimal percentage in modifying the performance characteristics of LEA is considered an innovation of this research. In this research, the performance characteristics of LEA modified by 10%, 15%, and 20% CR were evaluated. In order to examine the rutting behavior, moisture sensitivity and fatigue resistance, dynamic creep, indirect tensile strength (ITS), and four-point bending beam tests were applied, respectively. The results of creep curves and flow numbers (FNs) indicated that modifying LEA by 15% increased the rutting resistance by 1.92 and 2.3 times, respectively, compared to the HMA specimen at the stress level of 207 and 310 kPa. Moreover, the evaluation of the creep strain slope revealed that modifying LEA significantly reduced stress sensitivity. ITS test showed an increase in tensile strength ratio by 22% in the specimen with 10% CR compared to the unmodified specimen. In the evaluation of fatigue resistance, while LEA containing 10% CR had almost similar results to the HMA specimen, other specimens represented a shorter fatigue life, so that with the increase in CR percentage, the fatigue life decreased. Determination of fatigue life by energy ratio and Rowe and Bouldin criteria showed similar results. Finally, by determining the plateau value (PV) in the ratio of the dissipated energy change method, the lowest PV was assigned to the 10% CR-modified LEA and HMA specimens, respectively.

A Review of Rubberised Asphalt for Flexible Pavement Applications: Production, Content, Performance, Motivations and Future Directions

The crumb rubber (CR) recycled from waste tyres could be a viable alternative in achieving green pavements that offer exciting new markets to global investors. Adding CR into flexible pavements enhances their performance and ensures environmental sustainability. This paper will discuss the production variables, CR sizes and contents, blending techniques, optimum bitumen contents, morphology, standard characteristics, rheological characteristics, mechanical performance, greenhouse gas emissions, energy consumption and life cycle cost. This review study found that compared to traditional asphalt mixtures, the CR-modified asphalts had superior performance and longer service life. However, the dearth of information on several factors in CR asphalt production, including greenhouse gas emissions, energy consumption and life cycle cost during recycling, causes many agencies in the global asphalt industry to continue employing costly, energy-consuming additives such as styrene-butadiene-styrene (SBS) instead of CR to enhance asphalt.

The effect of the crumb rubber type and amount on dry process modified asphalt mixture and on low-temperature cracking and high-temperature rutting

ABSTRACT One of the best examples of circular economy is the application of crumb rubber for asphalt mixture or bitumen modification. The main objective of this study was to determine the effect of crumb rubber type and amount on dry process modified asphalt mixture performance in terms of rutting resistance, water sensitivity, air void content, stiffness, resistance to fatigue and low-temperature cracking. The study shows that the use of untreated crumb rubber increases the air void content by up to 2.7% compared to the reference mixture while the use of treated crumb rubber reduces air void content up to 0.9%. The use of untreated and treated crumb rubber from 0.5% to 3.0% has a negative effect on water sensitivity (strength decreases by 59.5%). The use of crumb rubber up to 1.5% has a positive effect on resistance to rutting, stiffness and resistance to fatigue (proportional rut depth PRDAIR is improved by 0.6–1.1%, stiffness – by 15.4–16.2% and resistance to fatigue – by 24.7–24.9%). This research revealed that the amount up to 3.0% of both types of crumb rubber has a positive effect on the resistance to low-temperature cracking (40.6–52.1%) comparing to the reference mixture with neat bitumen.

Effects of Tire Crumb Rubber and Steel Fiber on Punching Shear Behavior of Two-way Alkali-activated Concrete Flat Slabs

As a result of the rapid increase in the demand for transportation vehicles recently, the accumulation of waste tires causes environmental problems. One of the methods that can contribute to the reduction of this environmental problem is the recycling of waste tires as a construction material in aggregate form. This research investigated the impacts of waste tire crumb rubber with/out steel fiber (SF) on the two-way punching-shear behavior alkali-activated concrete (AAC) flat slabs and performed center point load tests. In the study, one-type of SF and two kinds of scrap tire waste i.e., crumb rubber (CR) and tire particles, were used on the producing of rubberized AAC slabs obtained by 100% as binder made of ground-granulated blast furnace slag (GGBFS). Also, while both fine crumb rubber (FCR) and coarse crumb rubber (CCR) were used together in the AAC slabs, tire crumb rubber (TCR) was used alone at the same proportion. Additionally, the fine aggregate was substituted with 10% and 15% FCR and CCR, and coarse aggregate was substituted with TCR in the same proportions. Additionally, AAC slabs with recycled tire rubber (RTR) were produced as fibrous and non-fibrous using 1% by volume hook-end SF. In total, nine AAC slabs with sizes of 50 x 50 x 6 cm3 were manufactured for the study. Experimental data showed that the inclusion of RTR only slightly reduced the punching shear strength of AAC slabs and the punching shear strength of the slabs increased when SF was added to the mixtures containing RTR.

PVA fiber-reinforced geopolymer mortar made with hybrid recycled aggregates: Toward thermal insulation, lightweight and improved durability

Polyvinyl alcohol (PVA) fiber-reinforced geopolymer mortar minimizes the shortcomings of large drying shrinkage and high brittleness of conventional geopolymer mortar made with natural sand. Replacing natural sand with crushed glass (CG) and crumb rubber (CR) aggregates is a sustainable alternative. However, their collaborative role in the performance of PVA fiber-reinforced geopolymer mortar remains unclear. To fill this gap, this research investigated the performance of a novel geopolymer mortar reinforced with 0–0.6 vol% PVA fibers and made with CG and CR aggregates with a mix ratio of 10:0–0:10. Due to different physical properties, CG and CR aggregates worked together to control their respective disadvantages. Compared to 100% CG, incorporating 30%–100% CR reduced the hardened density by 8.33%–27.13% and the thermal conductivity coefficient by 44.37%–82.17%. For 0.6 vol% PVA fibers, the 28-d drying shrinkage and 364-d alkali-silica reaction expansion decreased by 10.24%–35.20% and 60.71%–72.50%, respectively.

Effects of aging behavior on macro and micro characterizations of surfactant–crumb rubber asphalt binders

Asphalt aging process degenerates the performance and shortens the lifetime of the pavement, while using warm mix additive and crumb rubber modifier can improve the main negative distress. In this study, aged crumb rubber modified asphalt binder (CRMAB) with and without surfactant (0.6% SK) additive were designed through rolling thin film oven and pressure aging vessel test. The dynamic shear rheometer, bending-beam rheometer, fourier transform infrared spectroscopy, and atomic force microscopy tests were conducted to identify the effects of aging behavior on the macro-rheological properties, chemical constituents, and morphological characteristics of CRMAB and surfactant–crumb rubber modified asphalt binder (S-CRMAB). The findings from micro and macro analysis showed that aging increases carbonyl, sulfoxide, and aliphatic components, decreases aliphatic branched components, causing higher high-temperature rheology, lower low-temperaturen and fatigue performance. However, SK improves its aging resistance and relaxation ability. Moreover, the appearance of uniform hills–valleys and “round and bright lamellar” structures on the surface of 3D and 2D topographic images of S-CRMAB, respectively, indicating the surface roughness decreases, and microstructural stability gets enhanced.

Bio-inspired functionalization of crumb rubber using polydopamine to enhance the performance of rubberized mortars

This paper explores a biomolecule, dopamine, to functionalize crumb rubber (CR) to enhance the performance of cement mortars made with the CR. This is inspired by marine mussels, which can attach to various substrates underwater using the adhesive protein L-3,4-dihydroxyphenylalanine in its byssus. Dopamine is a mimic of the adhesive protein of mussel. At pH = 8.5, dopamine can spontaneously self-polymerize on the CR surface through the oxidation and the subsequent cross-linking of the catechol structure to form uniform polydopamine (PDA) film. This can enhance the wettability of the CR, leading to higher fluidities of the produced mortar. More importantly, the PDA film can chelate with Ca2+, promoting the formation of a denser interface transition zone between the CR and the cement paste and accelerating the hydration of the cement. As a result, the compressive strengths of the produced mortars were improved by 1–24 % at 3d, 13–52 % at 7d, and 37–68 % at 28d. The capillary water absorptions of mortars were also reduced by 28.6–41.8 %, significantly enhancing the durability of the mortar.

Performance of Stone Matrix Asphalt Modified with Crumb Rubber and Fibres

This article investigates the impact of Crumb Rubber Modified Bitumen (CRMB) and fibre additives (aramid fibre and basalt fibre) on the performance properties of Stone Matrix Asphalt (SMA) mixtures. Tests were conducted to evaluate mix design, draindown, cantabro loss, moisture sensitivity, rutting resistance and fatigue behavior. The Marshall method, the draindown parameters (ASTM D6390-11) and the cantabro loss characteristics (ASTM D 7064) were used to examine the mix design qualities. The modified Lottman test was used to assess the moisture sensitivity of SMA mixes. The roller compactor cum rut analyzer was used to assess rutting resistance. Findings showed that CRMB and fibre additives effectively controlled binder draindown and minimized abrasion loss in SMA mixtures. SMA-CRMB mixtures had higher draindown, but comparable cantabro loss than SMA-AF and SMA-BF mixtures. Incorporating CRMB and fibre additives enhanced moisture sensitivity, rutting resistance and fatigue behavior. SMA mixtures with 0.3% fibre addition displayed similar performance properties to SMA with CRMB. Further, substituting fibre additions for CRMB in SMA combinations may yield similar performance. KEYWORDS: Stone matrix asphalt, Crumb rubber-modified bitumen, Fibre additives, Draindown, Cantabro loss, Moisture sensitivity, Rutting resistance, Fatigue behaviour.

Properties of sustainable self-compacted concrete with recycled concrete and waste tire crumb rubber aggregates

The concrete building industry has to adhere to stringent sustainability standards. In previous investigations, the utilization of recycled concrete aggregates (RCA) from construction and demolition waste (CDW) or crumb rubber (CR) from waste tires in producing sustainable self-compacted concrete (SCC) was well studied; however, the combined effect of RCA and CR on the performance of SCC is scarce. Therefore, the main purpose of this study is to evaluate the feasibility of developing SCC mixtures containing both RCA and CR and their influence on the performance of SCC. Three distinct series of SCC mixes were designed so that the water-to-binder ratio and total binder content were kept at 0.32 and 505 kg/m3. In the first series, the effect of RCA content (0%, 50%, and 100%) in place of natural coarse aggregate (NCA) on the performance of SCC mixtures was studied. Moreover, the effect of various CR contents (0%, 10%, 20%, 30%, and 40%) as a sand substitution and 50% RCA was investigated in the second series. In the third series, the influence of CR inclusion and 100% RCA was utilized to promote the sustainability of SCC. The fresh behavior of the mixtures was assessed by measuring followability, viscosity, and segregation resistance. Density, water absorption, and apparent porosity for all mixes were also examined. The mechanical properties were assessed for compressive, splitting tensile, and flexural strengths. The findings show that the inclusion of RCA and CR has an adverse impact on the fresh, physical, and mechanical properties of SCC, excluding segregation resistance. However, it is possible to produce a SCC using 100% RCA and 40% CR with a slump flow diameter of 605 (SF1 class) and a compressive strength of greater than 31 MPa, which is applicable for structural applications. Moreover, the ACI and Euro code CEB-FIP proposed models can predict the mechanical properties of the developed SCC made with recycled materials. This research could contribute to a more sustainable SCC by substituting recycled materials for natural aggregates.

Nanoscale evolution of rubber-oil modified asphalt binder after thermal and UV aging

Thermal oxidation and ultraviolet exposure cause complex micro-scale chemical changes in asphalt binders, leading to severe deterioration of pavements. The aging-induced evolution of nanoscale domains in asphalt binders was investigated using multiple nanoscale characterizations. This in turn provides insights to develop means of alleviating the aging of asphalt binders to extend pavement service life. The chemical composition, surface topography, and mechanical properties of four asphalt binders (base asphalt and modified asphalt with bio-oils and crumb rubber) are investigated by atomic force microscopy during thermal aging and UV aging and a combination thereof. It was shown that the three domains in the asphalt binder react differently to aging. Abundant carbonyl and sulfoxide compositions are observed in the aged base asphalt binder, which is mainly generated and concentrated in the para domains. The addition of rubber and bio-modified rubber reduces the formation of aging-related compositions in para domains, thereby enhancing the aging resistance of asphalt binder. Aging also significantly changes the surface roughness and domain structures of asphalt binders. Furthermore, it was shown that the domain stability during thermal aging and UV aging can be enhanced by crumb rubber and bio-oils, respectively. Nano-mechanical characterization shows the surface of asphalt binders becomes stiffer, and its adhesion is reduced after aging. Significant reduction (up to 26%) in latter aging indicators was observed with the bio-modifier used in rubberized asphalt. This paper provides insights pertaining to the aging-induced evolution of asphalt binders while examining the efficacy of bio-modification of rubberized asphalt to delay aging. It is recommended to include hybrid aging in future studies and to test bio-modified rubberized asphalt at a larger scale.

Swelling-degradation dynamic evolution behaviors of bio-modified rubberized asphalt under thermal conditions

The incorporation of bio-oil, derived from agricultural waste, as a partial substitute for asphalt, coupled with the modification of asphalt using crumb rubber from waste tires, synergistically enhances both sustainability and performance, resulting in bio-modified rubberized asphalt (BMR). Nevertheless, the properties of BMR are subject to fluctuations due to the interplay of crumb rubber swelling-degradation and asphalt aging, particularly under thermal conditions. This research delineates the temporal evolution of BMR's properties, with an emphasis on its rheological, chemical, and microscopic attributes. Three distinct phases were observed: initially, crumb rubber absorbed bio-oil, thereby swelling and augmenting high-temperature performance via the micro-skeletal effect. Subsequently, during the intermediate phase, rubber degradation manifested as macroscopic softening in the modified asphalt. Lastly, the aging of the asphalt resulted in hardening. The multi-stage properties of BMR are governed by the dynamic equilibrium between rubber swelling, degradation, and asphalt aging. These observations offer valuable insights for the quality control of BMR, thereby advancing waste reduction and recycling in downstream applications.

Utilization of Crumbs from Discarded Rubber Tyres as Coarse Aggregate in Concrete: A Review

This research work successfully reviewed twenty-five papers on waste rubber tyres and their related areas. The chemical and physical properties of concrete constituents such as cement, water, sand and rubber crumbs were reviewed together with their mix ratios. The use of Tyre Rubber Crumbs (TRC) to replace coarse aggregates makes concrete construction work cheaper and its low water absorption rate improves the concrete mix properties such as compressive strength and workability. Hence, in road pavement construction, the use of TRC in asphalt modification is the best and smartest innovation for sustainable development and waste material reuse. This research showed that waste TRC are very essential in the replacement of some aggregates in the construction industries resulting in very high-quality construction and as well minimize construction costs.

Innovative Use of Waste PET-Derived Additive to Enhance Application Potentials of Recycled Concrete Aggregates in Asphalt Rubber.

Polyethylene terephthalate (PET) drinking bottles, rubber tires, and concrete are the very common municipal solid wastes, which are usually disposed of at landfills and stockpiles and cause continuous damage to the environment. Some studies have indicated that waste PET can be chemically converted into an additive for improving the overall properties of asphalt pavement incorporating natural aggregates, especially the moisture-induced damage resistance. However, it is not clear whether this PET additive still works for asphalt rubber containing recycled concrete aggregates (RCA). To well reveal this issue, this study first adopted a similar way to chemically recycle waste PET into the additive for modifying crumb rubber modified asphalt (CRMA) binder and then mixed the binder with the 13 mm maximum aggregate stone matrix asphalt containing 100% coarse RCA for preparing the mixtures. After a series of physicochemical characterizations of the PET additive, the moisture resistance, rutting resistance, low-temperature cracking resistance, and fatigue resistance of the mixture were systematically evaluated. The results showed that the PET additive is capable of improving the resistance to moisture and high-temperature deformation of asphalt rubber and helps greatly reduce the moisture-induced damage to the interfacial bonding layer. To be more detailed, the residual Marshall stability (RMS) value of RCA-CRMAM/1PET after 72 h of immersion is higher than 85% by contrast to that of RCA-CRMAM (77.1%), while the tensile strength ratio (TSR) value of RCA-CRMAM/1PET shows more than 80% compared to that of 65.2%. In addition, only 1% PET additive can enhance the high-temperature resistance of asphalt rubber containing RCA to rut and allow it to maintain higher resistance to rut after moisture-induced damage. 1% PET additive can help improve the bearing capacity of RCA-CRMAM under a low-temperature environment and delay its fatigue life at small stresses. Generally, with the successful introduction of PET additives to asphalt rubber containing RCA, more durable and sustainable highway pavement can be produced and applied in practice to alleviate the negative impacts caused by waste PET, waste tire rubber, and waste concrete.

Natural Rubber Latex-Modified Concrete with PET and Crumb Rubber Aggregate Replacements for Sustainable Rigid Pavements

There are ongoing research challenges for the addition of the blend of PET and crumb rubber in polymer-modified concretes, which aims to leverage the benefits of both materials. In this study, various percentage combinations of waste aggregates, such as PET and crumb rubber, were used to replace coarse and fine aggregates in natural rubber latex (NRL)-modified concrete. Engineering properties such as compressive and flexural strengths, modulus of elasticity, and toughness obtained from compressive- and flexural stress-strain curves were investigated. Scanning electron microscopy (SEM) analysis was performed to examine the microstructural properties and study the strength development of the studied concretes. The results revealed that the compressive and flexural strengths of NRL-modified concretes with PET and crumb rubber aggregate replacements decreased with increasing replacement ratios. SEM analysis indicated that PET and crumb rubber (hydrophobic and non-polar materials) can affect the microstructure of the studied concrete by creating a weak interface between the aggregate and cement pastes, leading to reduced strength development. With the addition of the NRL additive, the film formation was found to act as a bridge and improve the bond strength of aggregates and hydration products in NRL-modified concrete. Furthermore, the integration of PET and crumb rubber aggregate can enhance the ability of the concrete to absorb energy and improve ductility. It was found that 10% of PET and crumb rubber aggregate replacement can be used for NRL-modified concrete as a rigid pavement, as its mechanical strengths satisfy the requirements set by the Department of Highways (DOH) in Thailand. This research helps repurpose waste materials and reduce the environmental footprint of concrete production.

Adsorption/desorption of mercury (II) by artificially weathered microplastics: Kinetics, isotherms, and influencing factors

While both mercury (Hg) and microplastics (MPs) are well-studied global pollutants, comparatively little is known about the interactions between them and the mobilization of Hg from MPs into organisms. We examined the affinity of Hg(II) to artificially weathered MPs, including polyamide (w-PA), polyethylene (w-PE), polyethylene terephthalate (w-PET), polyester fibers (w-PEST), polyvinyl chloride (w-PVC), and polylactic acid (w-PLA), along with crumb rubber (CR) and PE collected from a wastewater treatment plant (WWTP-PE). WWTP-PE, CR, and w-PEST had particularly high Hg(II) affinities, which can be attributed to electrostatic interaction and pore filling. The adsorption followed a pseudo-second-order kinetic process and fitted the Freundlich model, suggesting multi-step (mass transfer and intraparticle diffusion) and heterogeneous adsorptions. Hydrochemical conditions (pH, dissolved organic matter (DOM), salinity and co-existent metal ions) all impacted Hg-MP behavior. Changes in Hg speciation and MP surface properties contributed to the different Hg(II) adsorption capacities for the MPs. Weathering of MPs generally increased the adsorption of Hg(II) onto MPs, but CR, PET and PEST did not follow this trend. Less than 3% of adsorbed Hg(II) was mobilized from the MPs in freshwater, but that increased up to 73% under simulated avian digestive conditions, suggesting increased bioavailability of Hg(II) from ingested MPs. Overall, weathered MPs adsorb and retain Hg(II) under environmentally relevant conditions but desorb much of it in simulated avian digestion fluid, suggesting that birds that ingest MPs may have increased Hg(II) exposure.

Performance evaluation and multiscale investigation of deodorant on mechanism of rubber modified asphalt

Asphalt fume emission caused by high-temperature is large during the production and construction of rubber modified asphalt, and the toxic and odor gas contained seriously pollutes the environment. This paper prepared rubber modified asphalt (RMA) and deodorant rubber modified asphalt (DRMA) and evaluated the impact of deodorants on the environmental and physical properties. Modern testing techniques, such as gel permeation chromatography, are used to explore the microscopic morphology of RMA, DRMA, and crumb rubber extracted from RMA and DRMA, so as to reveal the mechanism of deodorant in asphalt. Meanwhile, the effect of deodorant was monitored from macro scales by applying electrochemical sensing technology. The results show inhibiting the degradation of rubber in asphalt is the main mechanism of deodorant. Deodorant can not only promote the swelling of rubber in asphalt and improve the stability of sulfur elements, but also capture the odor particles in asphalt fume, reduce the concentration of polluting organic and H2S, realize the application of rubber modified asphalt environmentally-friendly, and promote the recycling of waste tires and the sustainability of pavements for pollution and carbon reduction.

Use of Rubber Crumb Obtained from Waste Car Tires for the Production of Road Bitumen and Roofing Materials from Residues of Ukrainian Oil Processing

The process of modifying road bitumen obtained from the residues of Ukrainian oils processing with rubber crumb has been studied. The dependence of the softening temperature, ductility, penetration, and elasticity of the three-component bituminous composition “bitumen : linseed oil : rubber crumb” on its formulation has been examined. Based on the mentioned composition a new type of cold-applied bitumen roofing has been developed. A process flow diagram for the production of modified bitumen and special-purpose bituminous composition has been developed.