Optimisation of Polymer Addition Using the Plackett-Burman Experiment Plan

At the present time, the utilization of waste polymer materials belongs to one of the most important challenges where global economies have to tackle. This article concerned the modification of petroleum road bitumen with waste polymer. The bitumen modification process with the use of polymeric materials was carried out considering a number of other quantitative factors, such as: mixing time, mixing speed, bitumen temperature and qualitative factors such as: waste polymer content, type of grain size, type of neat bitumen and type of waste polymer. Two kinds of waste polymers (PET, PP) were used in the research, which served as a modifier. Two petroleum bitumens were used: 20/30 (hard) and 70/100 (soft). Based on the divalent Plackett-Burman experiment plan, the number of variables and the number of combinations of mixtures were determined, which were required to determine the final response surface model. The following features were tested as the output variables: penetration, softening point, Fraass breaking point, dynamic viscosity 60oC, 90oC, 135oC, deformation energy and maximum elongation. The use of the experimental design methodology allowed to identify the factors that had the greatest impact on the bitumen modification process. The assessment of the significance of the parameters also allowed to identify a significant model allowing to find the optimal bitumen and waste polymer composition. Based on the test results, it was shown that the consistency of the modified bitumen was influenced by the type of bitumen, its amount, mixing speed and mixing time. With regard to the softening point, the type of polymer was also an important factor. Ultimately, the optimization process allowed for the determination of such a combination of both qualitative and quantitative input factors, which resulted in bitumen showing higher utility than input 20/30 and 70/100 bitumens. Moreover, it was found that the increase in mixing time did not result in an excessive increase in bitumen stiffness caused by the mixing process. Thus, the low-temperature properties left unchanged significantly

Performance Evaluation of Asphalt Binder Modified by Natural Rock Asphalt

Rock asphalt is one of the widely distributed resources in nature. Therefore, this study employs natural rock asphalt as an additive. The focus of this study is to look at the potential of using natural rock asphalt as an asphalt binder modifier. The study looks at five different percentages of modified asphalt (NRA) concentration from Anbar factory asphalt for oxidized bitumen: 0%, 5%, 10%, 20%, and 30%. The results show that using modified natural rock asphalt increased the mechanical qualities of basic asphalt, such as penetration and softening point, flash point, and viscosity. In addition, the current results show that the asphaltic materials that can be used in paving according to the measuring of conventional tests such as ductility, penetration, and others. Furthermore, the findings indicate that modified asphalt has lower temperature sensitivity.

Effects of Short-Term Ageing Temperature on Conventional and High-Temperature Properties of Paving-Grade Bitumen with Anti-Stripping and WMA Additives

The presented study explores the effects of decreased temperatures utilized in rolling thin-film oven (RTFOT) laboratory short-term ageing of asphalt binders based on 35/50- and 50/70-penetration paving-grade bitumen. Additionally, the effects of three additives used with these binders at different concentrations are evaluated: liquid anti-stripping agent, liquid warm-mix additive, and solid warm-mix additive. The resulting asphalt binders were subjected to basic (penetration at 25 °C, softening point, dynamic viscosity) and functional high-temperature characterization (G*/sin(δ), high critical temperature, non-recoverable creep compliance). It was found that the decreased short-term ageing temperatures may detrimentally impact the high-temperature grade of bituminous binders, but this effect can be mitigated by the use of appropriate additives. What is more, it was found that bituminous binders may respond differently to the aforementioned factors. Based on the results, it is advised that asphalt binders intended for use in warm-mix asphalts should be thoroughly tested to appropriately simulate the mixture production process and its effects.

Effect of M-resin-based Stabilizer on the Performance of SBS Modified Asphalt

Industrial solid waste M-resin (MR) contains high sulfur content which was difficult to be comprehensively utilized. According to the vulcanization reaction mechanism, MR was used as vulcanizing agent, nano zinc oxide (ZnO) as an activator, tetramethyl thiuram disulfide (TMTD) as an accelerator to produce M-resin-based stabilizer. MR (0.5, 1, 1.5, 2, 2.5), ZnO (0.1, 0.2, 0.3, 0.4, 0.5) and TMTD (0.06, 0.08, 0.1, 0.12, 0.14) were mixed with different contents, a three-factor and five-level orthogonal experiment was designed to test the penetration, ductility, softening point and 48 h softening point difference of SBS modified asphalt. Based on the four indexes, the basic formula of the stabilizer was obtained. The influence of kaolin, an auxiliary material, on the thermal stability was compared, and the formula were optimized, the appropriate dosage was determined. The microscopic morphology of the modified asphalt and SBS developmental fineness was analyzed with the fluorescent microscopy technology, and the SBS developmental fineness was studied with the generated binary graph and skeleton graph. DSR test was carried out to detect rheological properties of modified asphalt with different dosages of MR-based stabilizes. The results show that MR can significantly improve the thermal storage stability of modified asphalt. The ratio of MR:TMTD:ZnO:Kaolin is 1.5:0.5:0.08:12, and the appropriate dosage is 1.02 %. The stabilizer can reduce the 48 h softening point difference 33.6 ℃, increase the softening point 13.6 ℃, decrease the penetration degree 9.7 mm, but it has little effect on 5 ℃ ductility index. The microscopic images show that a cavity two-phase continuous network structure is formed inside the modified asphalt under the appropriate dosage of M-resin-based stabilizer. The SBS developmental fineness is 2.36 μm, and the uniformity is good. DSR test also shows that stabilizer can effectively improve the high temperature performance of SBS modified asphalt.

Identifying the Long-Term Thermal Storage Stability of SBS-Polymer-Modified Asphalt, including Physical Indexes, Rheological Properties, and Micro-Structures Characteristics

The thermal storage stability of styrene–butadiene–styrene tri-block copolymer modified bitumen (SBSPMB) is the key to avoid performance attenuation during storage and transportation in pavement engineering. However, existing evaluation index softening point difference within 48 h (ΔSP48) cannot effectively distinguish this attenuation of SBSPMB. Thus, conventional physical indexes, rheological properties, and micro-structure characteristics of SBSPMB during a 10-day storage were investigated in this research. Results showed that during long-term thermal storage under 163 °C for 10 days, penetration, ductility, softening point, recovery rate (R%), and anti-rutting factor (G*/sinδ) were decayed with storage time increasing. This outcome was ascribed to the phase separation of SBS, which mainly occurred after a 4-day storage. However, ΔSP48 after a 6-day storage met the specification requirements (i.e., below 2.5 °C). Thus, the attenuation degree of asphalt performance in field storage was not effectively characterized by ΔSP48 alone. Results from network strength (I) and SBS swelling degree tests revealed that the primary cause was SBS degradation and base asphalt aging. Moreover, conventional indexes, including penetration, ductility, and softening point, were used to build a prediction model for rheological properties after long-term storage using partial least squares regression model, which can effectively predict I, R, Jnr, G*/sinδ, and SBS amount. Correlation coefficient is above 0.8. G*/sinδ and I at the top and bottom storage locations had high coefficient with SBS amount. Thus, phase separation of SBSPMB should be evaluated during thermal storage.

The Results of the Compromise Task Solution Directed for Development of Polymer-Modified Binder

This work presents the results of optimization compositions of polymer-modified binder (PMB) by a compromise task. The conducted study of influence two prescription factors – containing styrene-butadiene-styrene and sulfur – on which is a set of indicators of polymer-bitumen binders were carried out. The regularities of these factors of mutual influence were established by such indicators as the Fraas brittleness temperature, penetration, softening point, ductility. The dosages of SBS and sulfur have been determined by ensuring the achievement of the required level of PBB indicators in accordance with GOST R 52056-2003 «Bitumen-polymer road binders are based on styrene-butadiene-styrene block copolymers. Specifications».

Preparation and performance characteristics of reduced graphene oxide modified asphalt

Reduced graphene oxide (RGO) was self-prepared by the oxidation reduction method and then characterized by several tests known as Fourier Transform Infrared Spectroscopy (FTIR) test, scanning electron microscopy (SEM) test, transmission electron microscopy (TEM) test, elemental analysis, raman measurement and thermogravimetry (TG) analysis to evaluate the properties of RGO. Additionally, RGO modified asphalt was prepared in this research to study the influence of RGO on matrix asphalt. Some of the normal performances of RGO modified asphalt were studied in terms of penetration at medium temperature, penetration index (PI), softening point, equivalent softening point T800 at high temperature and ductility at low temperature. Results showed that the prepared RGO has obvious layer structures and good properties and the performance of RGO modified asphalt at high temperature has increased significantly while the performance at low temperature decreased slightly. This research can provide an insight for the further study of RGO modified asphalt to enhance its road performance.

The Synergistic Effect of Temperature and Loading Rate on Deformation for Thermoplastic Fiber Metal Laminates

The glass fiber reinforced polypropylene/AA2024 hybrid laminates (short for Al/Gf/PP laminates) as structural materials were prepared and formed by hot pressing. The synergistic effects of temperature and loading speed on the laminate deformation under tensile and bending conditions were investigated and analyzed in this study. In tension, stress–strain curves presented bimodal types effected by tensile rates and temperatures. The state of PP resin determines the mechanical behavior of the FMLs. The tensile rate has no effect on FML deformation without heating or over the melting point of PP resin (about 170 °C). The softening point of PP resin (about 100 °C) is characteristic temperature. When the temperature exceeds the softening point but does not reach the melting point, the tensile strength and elongation will demonstrate coordinated growth at a relatively high tensile speed. The efficiency of fiber bridging is affected significantly since the resin is the medium that transfers load from the metal to the fiber. Under bending, the curves presented a waterfall decrement with temperature increment. The softening point of resin matrix is the key in a bending process. When the temperature is near the softening point, deformation is sensitive to both the temperature and the loading speed to a certain extent. If temperature is lower than softening point, deformation is mainly guided by temperature. If the temperature is beyond the softening point, loading speed is in a leading position of deformation. The bending strength gradually increases with loading rate. By using these deformation characteristics, the deformation of the thermoplastic laminates can be controlled in stamping or other plastic forming processes for thermoplastic fiber metal laminates.

Effects of a Fuel-Resistant Modifier on the High-Temperature Characteristics of Asphalt Binders

To effectively evaluate the high-temperature characteristics of a fuel-resistant modified asphalt (FRMA), five different types of asphalt were selected, and a fuel-resistant modifier (FRM) was added to the asphalt to prepare five kinds of FRMA, and the fuel resistance of the 10 above-mentioned asphalt samples was then evaluated. Moreover, the high-temperature performance of different asphalt samples was explored, the influences of the FRM on the penetration, softening point, and rheological indexes of the different asphalt samples were analyzed. A Pearson correlation analysis was conducted on the different high-temperature indexes. Based on the results, compared with the original asphalt, the fuel resistance of the FRMA was improved by about 22% on average; the FRM was able to reduce the penetration, phase angle, and non-recoverable creep compliance of the asphalt; increase the softening point, complex modulus, rutting factors, and creep recovery; and effectively improve the high-temperature performance of the asphalt. However, as the temperature increased, the effect of the FRM on the improvement of the high-temperature performance of the asphalt declined. In addition, compared with the base asphalt, the FRM exerted a more significant effect on the rheological properties of the modified asphalt. According to the Pearson correlation analysis of the high-temperature indexes, apart from penetration, the softening point and rheological indexes featured excellent accuracy and applicability in the evaluation of the high-temperature performance of FRMAs.

Investigating the Effect of Addition of Olive Husk Ash on Asphalt Binder Properties

Flexible pavement is the preferred pavement type in construction of roads and highways. A huge amount of non-renewable materials and industrial products like Olive Husk Ash (OHA), aggregates, bitumen, cement, lime, and other additives are used during the construction and maintenance of the pavement system. Needless to say, the extraction and production of these materials are unmaintainable. Moreover, the wastage of materials, the worsening environmental conditions, the insufficient resources, and the increasing cost of material urged the researchers to look for alternative materials that can be used in flexible pavement. Jordan as many other Mediterranean countries produces a substantial amount of olive oil every year, which in turn produces an enormous amount of olive waste that could lead to environmental problems. Up to now, there is no efficient or certain way in which olive oil waste could be handled or used except that it is sometimes used for heating purposes. The current research aims to evaluate the effects of Olive Husk Ash (OHA) on asphalt binder properties such as penetration ductility, softening point, fire and flashpoint, and specific gravity. In the current research, OHA is used as an additive (0%, 5%, 10%, 15%, and 20%) of asphalt-cement. Tests on OHA-asphalt binder properties are conducted and results are reported. Results of experimentation and analyses indicate that increasing OHA content in the asphalt-cement binder has resulted in a reduction of both penetration and ductility and an increase in specific gravity, softening point, and fire and flashpoint.