Development of Statistical Models of the Effects of Waste Engine Oil (WEO) on Different Grades of Asphalt

Rejuvenation of aged asphalt binder extracted from reclaimed asphalt pavement using waste vegetable and engine oils

This study attempts to investigate the viability of using waste engine oil (WEO) and waste cooking oil (WCO) as rejuvenator in asphalt concrete containing reclaimed asphalt pavement (RAP). Different percentages of the waste oils, namely 0, 5, 10 and 15% (by the weight of total binder) have been added into an asphalt concrete containing, 25, 50 and 75% of RAP and the effects on creep and fatigue properties have been investigated. The rutting resistance was found to increase with adding RAP, with lower increase for adding 50% RAP than 25 and 75%, and decrease with adding WEO and WCO, with lower decrease for adding 10% than adding 5 and 15%. Stress controlled fatigue tests showed that the fatigue resistance of non-rejuvenated mixtures grows with increasing RAP content, and, in general, the increase of WEO/WCO dosage results in the decrease of fatigue life. At the same dosage of rejuvenator, WEO results in more fatigue life than WCO, indicating that higher WEO is allowed to be used in recycled mixtures.

NaOH, dolomite and NiCl2 were used as catalysts to examine their effects on co–pyrolysis with waste bicycle tires (WT) and waste engine oil (WEO). The pyrolysis behaviors with catalysts were investigated by thermogravimetric analysis. The activation energy of the catalytic main reaction stage was derived by the Kissinger–Akahira–Sunose (KAS) method under four different heating rates conditions. The calculations show that all three catalysts can reduce the activation energy of the reaction. Co–pyrolysis of WT and WEO with different catalysts was performed in a self–made lab bench at 600 °C to explore the impact on the distribution of three–phase products. The properties of gas and oil products were characterized by FTIR and Py–GC/MS (Agilent 7890B, Santa Clara, CA, USA). With the mixing of catalysts, activation energy (Eα) decreased by 15–30% in the main reaction process. NaOH and dolomite increased the yield of gas by 7% and 10%. NaOH can significantly improve the yield of CH4. The proportion of limonene in pyrolysis oil increased to 19.65% with 10% NaOH. This article provides a new method for efficiently producing limonene by mixing WT and WEO with NaOH.

The effects of using waste engine oil (WEO) and waste cooking oil (WCO) as rejuvenators on some engineering properties of asphalt concrete containing reclaimed asphalt pavement (RAP) have been studied. 10% (by the weight of total binder) of the rejuvenators has been added to asphalt concrete containing 25%, 50% and 75% (by the weight of aggregate) of RAP, and the Marshall properties, indirect tensile strength (ITS), permanent deformation and fatigue properties of the mixtures have been evaluated. The effect of rejuvenators on Marshall properties depends on RAP content and type of rejuvenator, with higher values for the mixtures containing WEO. The ITS of the mixtures increase with increasing RAP content, and decreases with increasing rejuvenators content. Addition of WEO results in lower accumulated strain in the mixtures than adding WCO. In addition, the accumulated strain in the mixtures containing 50% of RAP is higher than that in the mixtures containing 25% and 75% of RAP. The fatigue life of the mixtures was found to increase with increasing RAP content and decrease by addition of rejuvenator with a higher reduction for the WCO. In general, it is concluded that using the rejuvenators enables using higher RAP content in recycled asphaltic mixtures.

Reclaimed asphalt pavement (RAP) is a sustainable and cost-effective way to reduce the need for virgin asphalt in road construction and rehabilitation. However, RAP is often hard and brittle, leading to performance problems. Rejuvenators can be used to restore RAP's physical and rheological properties, but many conventional rejuvenators are petroleum-based and have environmental drawbacks. The objective of this study is to assess the rutting and moisture resistance characteristics of reclaimed asphalt mixtures rejuvenated with waste engine oil (WEO), with a particular focus on regions characterized by hot climates, such as Iraq. This study investigated WEO as a rejuvenator for RAP and oxidized asphalt grade 30–40. WEO is a waste product that can be recycled and reused, making it a sustainable and environmentally friendly rejuvenator. The study found that asphalt mixes containing RAP rejuvenated with WEO had improved mechanical performance compared to conventional asphalt mixes. Marshall stability increased by up to 30%, indirect tensile strength increased by up to 29%, moisture resistance improved by up to 19%, resilience to stripping increased by up to 97%, and rutting resistance increased by up to 64.5%. The study findings suggest that asphalt mixtures containing RAP rejuvenated with WEO are a promising new technology for sustainable road construction and rehabilitation. WEO is a waste product that can be recycled, reused, and used to produce asphalt mixes with improved mechanical performance. The novelty of this study is the use of WEO as a rejuvenator for RAP. WEO is a waste product that can be regenerated and reused, making it a sustainable and environmentally friendly rejuvenator. The study also investigated the optimal WEO concentration for rejuvenating RAP asphalt mixes, which is important for producing asphalt mixes with the desired performance characteristics.

The study investigates changes in the mechanical, thermal, morphological and physical properties of recycled low density polyethylene (LDPE) composites made with percentages (10 wt%, 20 wt%, 30 wt.%) of old newspaper fiber (ONF) and waste engine oil (WEO) (1 wt.%). The composites were manufactured by a single screw extruder. Adding WEO up to 20 wt% of ONF had a positive effect on the flexural properties, while the incorporation of WEO up to 10 wt % of ONF showed an affirmative effect on the tensile properties of the composites. The highest flexural strength was achieved in A3 (13.19 MPa) and B3 (12.3 MPa) samples for ONF added composites and ONF/WEO composites, respectively. Adding to the WEO decreased the water absorption values of the recycled low density polyethylene composites. Differential scanning calorimetry analysis showed that the addition of 1% WEO, the crystallinity of the composites decreased to about 30%. In the light of the results, the WEO could be successfully used with old newspaper in a polyethylene matrix.Highlights The highest tensile strength was achieved in the B3 sample (with WEO). The highest flexural strength was achieved in the B3 sample (with WEO). The highest tensile was obtained from the A3 sample (without WEO). The highest flexural strength was obtained from the A3 sample (without WEO). The crystallinity of the composites decreased to about 30%.

In this research, the permanent deformation property of asphalt concrete containing different percentages of recycled asphalt pavement (RAP) and dosages of waste engine and cooking oil has been investigated using response surface methodology (RSM). 25, 50 and 75% of total aggregates have been replaced with RAP, and each rejuvenated with 5, 10 and 15% (by the weight of total binder) of waste engine oil (WEO) and waste cooking oil (WCO). Experiments were designed using composite central design method in RSM, and the permanent strain accumulated after applying 1000 cycles of 300 kPa vertical stress at a frequency of 1 Hz and temperature of 40 °C was measured. Using RSM in Design Expert program, a polynomial quadratic model was found to be capable for predicting the permanent strain. It was found that the significant terms for prediction of permanent strain are RAP and oil content, the squared oil content and type of oil. Results reveal that permanent strain decreases with increasing RAP content; however, for each RAP content, the lowest permanent strain is achieved at a certain level of oil content. At the same dosage of use, WEO results in lower strain than WCO. Interaction effect was found between RAP content and oil type, such that the decrease of strain with RAP content is higher with WCO than WEO. Using optimization in RSM, the content of oils to achieve a mixture with similar deformation property of control mix was obtained.

Insight into co-pyrolysis of waste polypropylene and engine oil for liquid hydrocarbons and interaction mechanism by kinetic analysis and DFT simulation

Collectors commonly have synergetic effects in ores flotation. In this work, a waste engine oil (WEO) was introduced as a collector to an ilmenite flotation system with sodium oleate (NaOL). The results show that the floatability of ilmenite was significantly improved by using WEO and NaOL as a combined collector. The recovery of ilmenite was enhanced from 71.26% (only NaOL) to 93.89% (WEO/NaOL combined collector) at the pH of 6.72. The optimum molar ratio of NaOL to WEO was about 2.08 to 1. The WEO and NaOL also have synergetic effects for the collection of ilmenite, because to obtain the ilmenite recovery of 53.96%, the dosage of 45 mg/L NaOL is equal to 38.56 mg/L WEO/NaOL combined collector (30 mg/L NaOL + 8.56 mg/L WEO). In other words, 15 mg/L of NaOL can be replaced by 8.56 mg/L of WEO. It is an effective way to reduce the dosage of the collector and reuse WEO. Therefore, it is a highly valuable and environmentally friendly approach for WEO reuse. WEO mainly consists of oxygen functional groups, aromatics, and long-chain hydrocarbons, especially for the RCONH2 and RCOOH, thereby forming a strong interaction on the ilmenite surface. The adsorption mechanism of waste engine oil and sodium oleate on the ilmenite surface is mainly contributed by chemical adsorption. Therefore, WEO exhibits superior synergistic power with NaOL as a combined collector. Herein, this work provided an effective collector for ilmenite flotation and a feasible approach for reducing NaOL dosage and recycling WEO.

The study of the thermal safety of emulsion explosives mixed with waste engine oil is very important for the safety of these types of explosives used in mine blasting. In order to study the thermal safety of emulsion explosives mixed with waste engine oil, thermal safety tests were carried out using a Differential Scanning Calorimeter (DSC), non-isothermal kinetics, and the Flynn–Wall–Ozawa method. The results show that the minor particle impurities in the filtered waste engine oil are mainly combustibles; after adding different amounts of waste engine oil, the activation energy of the emulsion matrix decreases from 110.33 kJ/mol to 75.39 kJ/mol, 74.50 kJ/mol, and 82.23 kJ/mol, and the critical temperature for thermal explosion changes from 194.16 °C to 169.73 °C, 227.47 °C, and 208.78 °C. The addition of waste engine oil reduces the activation energy of emulsion explosives. The waste engine oil is negatively correlated with the activation energy and the thermal explosion reaction temperature of emulsion explosives, and the correlation coefficient is −0.686 and −0.333. The emulsifier is positively correlated with the critical temperature of thermal explosion of emulsion explosives, and the correlation coefficient is 0.251. The small particles in the waste engine oil create a hot spot in the emulsion explosives, which reduces the thermal safety of the emulsion explosives mixed with waste engine oil. The emulsifier reduces the droplet size of the emulsion explosive, improves the oil-water interface strength, and improves the thermal safety of the emulsion explosives mixed with waste engine oil. The thermal safety of emulsion explosives mixed with waste engine oil can be improved by reducing the proportion of the sensitizer and increasing the proportion of the emulsifier.

This research aims to explore the high-temperature and low-temperature performances of lignin–waste engine oil-modified asphalt binder and its mixture. For this research, the lignin with two contents (4%, 6%) and waste engine oil with two contents (3%, 5%) were adopted to modify the control asphalt binder (PG 58-28). The high-temperature rheological properties of the lignin–waste engine oil-modified asphalt binder were investigated by the viscosity obtained by the Brookfield viscometer and the temperature sweep test by the dynamic shear rheometer. The low-temperature rheological property of the lignin–waste engine oil-modified asphalt binder was evaluated by the stiffness and m-value at two different temperatures (−18 °C, −12 °C) obtained by the bending beam rheometer. The high-temperature and the low-temperature performances of the lignin–waste engine oil-modified asphalt mixture were explored by the rutting test and low-temperature bending beam test. The results displayed that the rotational viscosity and rutting factor improved with the addition of lignin and decreased with the incorporation of waste engine oil. Adding the lignin into the control asphalt binder enhanced the elastic component while adding the waste engine oil lowered the elastic component of the asphalt binder. The stiffness of asphalt binder LO60 could not meet the requirement in the specification, but the waste engine oil made it reach the requirement based on the bending beam rheometer test. The waste engine oil could enhance the low-temperature performance. The dynamic stabilities of LO40- and LO60-modified asphalt mixture increased by about 9.05% and 17.41%, compared to the control mixture, respectively. The maximum tensile strain of LO45 and LO65 increased by 16.39% and 25.28% compared to that of LO40 and LO60, respectively. The high- and low-temperature performances of the lignin–waste engine oil-modified asphalt LO65 was higher than that of the control asphalt. The dynamic stability had a good linear relationship with viscosity, the rutting factor of the unaged at 58 °C, and the rutting factor of the aged at 58 °C, while the maximum tensile strain had a good linear relationship with m-value at −18 °C. This research provides a theoretical basis for the further applications of lignin–waste engine oil-modified asphalt.

The ability to recycle large amounts of asphalt pavement hinges on the capability of restoring the properties of the aged asphalt binder contained within the old pavement to that of virgin binder. Common practice in asphalt pavement recycling is to blend reclaimed asphalt pavements (RAP) with a recycling agent to chemically restore the aged asphalt binder. Waste engine oil from automobiles has been shown to improve asphalt binder when applied in small quantities, with the added advantage of being a waste product itself. Using waste engine oil as a chemical additive to restore the properties of RAP uses one waste material to increase the recyclability of another, which is environmentally and socially desirable.In this study, a PG 58-28 neat, virgin binder was blended with reclaimed asphalt binder (RAB) and waste engine oil. The blends were then tested to study the interactions between RAB and waste engine oil. Using Fourier-Transform Infrared Spectroscopy (FT-IR), the differences in the samples were compared using the structural indices associated with asphalt binder aging. This testing revealed a decrease in the two aging indices of the blended asphalt binder, indicating that waste engine oil has the ability to chemically restore aged asphalt binder.Asphalt mixture testing was then performed with mixtures of virgin asphalt, virgin binder, RAP and waste engine oil, in quantities similar to the binder testing, to see if the rejuvenation shown in FT-IR led to an improvement in the performance of the pavement specimens. After specimens were created, testing for freeze thaw durability, and rutting susceptibility was conducted. The results of the mixture testing failed to show an improvement of the freeze thaw durability or rutting susceptibility of specimens created with RAP and waste engine oil when compared to mixtures containing only new materials.

This study tackles the environmental challenges associated with the growing accumulation of waste plastic (WP), specifically recycled low-density polyethylene (R-LDPE), by examining its impact on the performance of asphalt binders amid extreme weather and heavy traffic conditions. The research investigates how R-LDPE modifies both virgin asphalt binder (VAB) and recycled asphalt binder (RAB) rejuvenated with 15% waste engine oil (WEO). Three proportions of R-LDPE (2%, 3%, and 4% by weight of VAB) were evaluated, with findings indicating that 2% is the optimal amount for enhancing binder properties. The study involved morphological, thermal, and chemical evaluations using scanning electronic microscope (SEM), energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). Additionally, comprehensive rheological and mechanical properties were assessed, including tests for penetration, softening point, rotational viscosity (RV), dynamic shear at high and intermediate temperatures, multiple stress creep and recovery (MSCR), and linear amplitude sweep (LAS). The results revealed that R-LDPE incorporation significantly improves the thermal stability, stiffness, and rutting resistance of asphalt binders, with modified RAB outperforming VAB in rutting resistance, while fatigue resistance was optimized with 2% R-LDPE. The MSCR test results further revealed enhanced elastic recovery and reduced creep, indicating superior resistance to repeated loading. The LAS test indicated an improvement in fatigue life and better resistance to crack propagation under cyclic loading. Overall, the use of R-LDPE and WEO enhanced the investigated binder’s durability and performance, making them more suitable for hot climates and high-stress applications.

Annually tons of waste engine oil is wasted or dumped in environmentally unfriendly ways. Asphalt binder has been modified with waste engine oil previously and showed, lower consistency, lower moisture damage resistance at higher dosages, and impaired high-temperature performance. In the current study, three different additives were added to solve these issues associated with waste engine oil-modified bitumen. Elvaloy, polyphosphoric acid (PPA), and hydrated lime (H-L) were used as polymer, chemical, and filler-type additives. Waste engine oil-modified bitumen combined with all three types of additives was evaluated using conventional viscosity, moisture susceptibility, dynamic mechanical, and chemical testing. Results showed that waste engine oil inclusion decreased the consistency of binder, reduced viscosity, and impaired high-temperature performance. Elvaloy’s addition to waste engine oil-modified bitumen made it less sensitive to temperature changes, increased the performance grade, improved the stiffness, and enhanced the resistance against rutting and moisture-induced damages. Polyphosphoric acid addition refined the consistency of binder modified with waste engine oil. It drastically increased the complex modulus values and decreased phase angle values by stiffening the binder. PPA enhanced the moisture susceptibility of asphalt and improved its high-temperature performance. Hydrated lime improved moisture resistance and bonding strength but showed less effectiveness in improving high-temperature performance at lower dosages. The results conclude that binder modification with waste engine oil can be effective with other additives like polyphosphoric acid, Elvaloy, and hydrated lime.

Age hardening of bitumen is one of the factors affecting the durability of asphaltic concrete pavements. As the bitumen ages, its viscosity increases and it becomes more stiff and brittle. Recycling agents have been used to restore or soften the aged bitumen properties to a consistency level appropriate for use in the recycling process of deteriorated pavements. This paper details a study on the use of Waste Engine Oil (WEO) from vehicles as a recycling agent for aged bitumen. The study focused on the rheological properties evaluation of virgin bitumen, aged bitumen and blended bitumen (50% of fresh bitumen + 50% of aged bitumen) mixed with waste engine oil as additive (with 0%, 3%, 6% and 9%). The aged bitumen was prepared through the process of Rolled Thin Oven Test (RTFOT) and Pressure Aging Vessel (PAV) test to simulate the aging process. The virgin bitumen, the aged bitumen, and the blended bitumen mixed with various proportions of WEO were then tested to determine their physical characteristics. Penetration, softening point, viscosity and dynamic shear rheometer (DSR) tests were conducted in order to determine rheological properties of the bitumen samples prepared. The penetration value of blended bitumen added with WEO increased with the addition of WEO. The softening point decrease with the percentage increased in WEO of the blended bitumen. The viscosity for the blended bitumen added with WEO decreases with the increase in the percentage of WEO added. The DSR results showed that the increase in the amount of WEO in blended bitumen decrease the G*/sin δ parameter. For the particular bitumen and WEO used, the optimum percentage of WEO is 6% by the total weight of bitumen as it complies with the Public Works Department of Malaysia’s specification requirements. This study suggests that WEO has ability to counteract the stiffening of aged bitumen and restore the aged bitumen to that of virgin bitumen. As the composition and performance of bitumen and WEO may be different from those used in this study, it is recommended that a detailed evaluation is carried out for the bitumen and WEO to be used in asphalt recycling.