Proposed Changes to Asphalt Binder Specifications to Address Binder Quality-Related Thermally Induced Surface Damage

Superpave specifications address binder properties that may lead to rutting, transverse cracking, and fatigue damage with varying degrees of success. However, asphalt binder production and formulation has significantly changed and introduced much more variability in relation to quality since the development of the Superpave Performance-Grade system because of economic, technical, and environmental reasons. Consequently, aged-induced surface distresses under combined thermal and traffic loading have become the main challenge for highway agencies. Thermally induced surface deterioration appears in the form of traditional transverse cracking, block cracking, and raveling, or accelerating damage at construction joints. This study evaluated the limitations of the proposed linear viscoelastic (LVE) rheological cracking surrogates, such as ΔTc, R-value, and G-R parameters, and the ability of the Asphalt Binder Cracking Device (ABCD) failure test to overcome these limitations. ABCD is particularly appropriate to rank binder performance because the measured cracking temperature (Tcr) encompasses binder LVE properties, failure strength, coefficient of thermal contraction, and cooling rate. The proposed parameter (ΔTf = Tc(S = 300 MPa) from BBR—Tcr from ABCD) relates the failure temperature to the equi-stiffness temperature and gives credit to well-formulated and compatible polymer-modified binders expected to increase binder strength and strain tolerance. This paper proposes a specification framework based on both ΔTc and ΔTf, universally applicable, regardless of binder composition. Additionally, preliminary purchase specification limits for binders used in surface layers are proposed based on the analysis of 44 binders, 15 with corresponding field performance data. Obviously, as confirmed by a recent stakeholder workshop and industry feedback, these preliminary specification limits need further validation and possible adjustments to account for regional experience and local challenges.

Impact of Bio-Ethanol, Bio-ETBE Addition on the Volatility of Gasoline with Oxygen Content at the Level of E10

This study examines the impact of the addition of bio-ethanol/bio-ETBE on the main volatility properties of gasoline. Although several studies have been published on the addition of ethanol or ETBE to gasoline, the simultaneous addition of these oxygenates has not been studied by taking the maximum oxygen content of 3.7% m/m into account. The EN 228:2012-A1:2017 standard specifies the requirements for marketed unleaded gasoline. This standard is able to determine, among other things, a gasoline type with a maximum oxygen content of 3.7% m/m and sets the maximum limits for ethanol content at 10% v/v and 22% v/v for ethers with a minimum five carbon atoms, such as ΕΤΒΕ. Five refinery fractions were mixed in various proportions and were used as base fuels. A total of 30 samples were prepared by blending the base fuels with bio-ethanol/bio-ETBE. In each of these base fuels, bio-ethanol was added in concentrations up to 10% v/v. Subsequently, bio-ETBE was added to each of these fuels in concentrations up to 20.8% v/v for use as a stabilizer. All of the samples were examined using the EN ISO 13016-1 and EN ISO 3405 test methods while considering the volatility requirements set by EN 228. The results showed that the addition of bio-ETBE has a beneficial effect on the volatility characteristics of the samples, as it reduces the vapor pressure of the final blend and sets all fuels in compliance with the required specification limits set by the EN 228 standard.

Artificial Neural Network Modelling for Asphalt Concrete Samples with Boron Waste Modification

Civil engineering science has evolved into the 21st century with concepts of recycling and sustainability. It is one of the most important goals of this century to create sustainable habitats by evaluating waste materials in building materials. This study aims to eliminate the boron waste dunes that have occurred and continue to occur in our country which has the world's largest boron reserves by using in road materials. Solid boron wastes obtained from the field were crushed and added to asphalt samples in certain ratios and the effect of Crushed Boron Waste (CBW) on asphalt samples were investigated. As a result of Marshall Design Method, it has been proved that boron wastes can be used in asphalt concrete within the specification limits. Besides, an artificial neural network (ANN) model was created for the evaluation of obtained data. As a result of Marshall Design Method, it has been proved that boron wastes can be used in asphalt concrete within the specification limits. Furthermore, examination of modelling and statistical analysis, mechanical performance of asphalt concrete samples with and without CBW addition has been predicted in noticeable manner. As a result of regression analysis, training and test sets r2 values are reached 0.95-0.91 for stability and 0.91-0.87 for flow values. Finally, a simulation was prepared with the created model and the effect of boron wastes on asphalt samples were examined in more detail.

Uncertainty of Size-Exclusion Chromatography Method in Quality Control of Bevacizumab Batches

In addition to the analytical challenges related to the size and complexity of biopharmaceutical drugs, the inherent variability that arises due to their manufacturing process requires monitoring throughout the production process to ensure the safety and efficacy of the finished product. In this step, validation data should demonstrate that the process is controlled and reproducible, whereas the manufacturing process must ensure the quality and consistency of the product. For this, the manufacturer sets specification limits according with regulatory guidance. In such a situation, the comparison of different batches is required in order to describe and analyze the variability between them. However, it is unclear how great the variability of the analytical method would be or that in producing the batches. The estimation of the β-expectation tolerance intervals based on the variance components to account for both between-batch and within-batch variability was proposed as a specification limit to control the heterogeneity between batches at the time of manufacture and to verify whether batches meet specification limits. At this point, the variance components were computed by the maximum likelihood method using a linear random model. For this, the protein content, expressed as a percentage of the actual concentration relative to the claim value, and the dimer content (expressed as percentage) were used as critical quality attributes (CQAs) in the monitoring and control process. We used real data from six bevacizumab commercial batches.

Pay Factor Analysis for Highway Pavements through Percentage of Material within Specification Limits and Monte Carlo Simulation

Many state highway agencies (SHAs) have adopted pay adjustment provisions in their acceptance plans for construction and materials. In these payment adjustment acceptance plans, the percentage of material within specification limits (PWL) has been selected as the quality measure to relate production quality to pay factors, and pay equations are used to determine a pay factor for a lot based on PWL. Various pay equations have been proposed by the highway community for adoption in SHAs’ specifications. However, the effectiveness of these pay equations has not been fully evaluated. Another issue concerning the pay adjustment acceptance plans is the risk associated with single and multiple pay factors. The purpose of this study was to evaluate the effects of different pay equations commonly used by SHAs and the risks associated with pay adjustment acceptance plans. This was achieved by developing operating characteristic curves associated with various pay factors and expected pay curves and Monte Carlo simulation for assessing the effects in the long run. The methodology suggested in this paper is transferable elsewhere where similar materials and specifications are used for the acceptance of pavements.

Quality and composition of Albendazole, Mebendazole and Praziquantel available in Burkina Faso, Côte d’Ivoire, Ghana and Tanzania

Background Even though the international combat against Neglected Tropical Diseases such as schistosomiasis or soil-transmitted helminthiases depends on reliable therapeutics, anthelminthic pharmacovigilance has been neglected on many national African drug markets. Therefore, quality and composition of Albendazole, Mebendazole and Praziquantel locally collected in Burkina Faso, Côte d’Ivoire, Ghana and Tanzania were analysed. Methods Samples of 88 different batches were obtained from randomly selected facilities. Sampling took place in Northwest Tanzania, Western Burkina Faso, Southeast Côte d’Ivoire and Southwest Ghana. Visual examination of both packaging and samples was performed according to the WHO ‘Be Aware’ tool. Products were then screened with the GPHF Minilab, consisting of tests of mass uniformity, disintegration times and thin-layer chromatography (TLC). Confirmatory tests were performed according to international pharmacopoeiae, applying assays for dissolution profiles and high-performance liquid chromatography (HPLC). Findings Despite minor irregularities, appearance of the products did not hint at falsified medicines. However, 19.6% of the brands collected in Ghana and Tanzania were not officially licensed for sale. Mass uniformity was confirmed in 53 out of 58 brands of tablets. 41 out of 56 products passed disintegration times; 10 out of the 15 failing products did not disintegrate at all. Evaluating TLC results, only 4 out of 83 batches narrowly missed specification limits, 18 batches slightly exceeded them. Not more than 46.3% (31 / 67) of the tablets assayed passed the respective pharmaceutical criteria for dissolution. HPLC findings confirmed TLC results despite shifted specification limits: 10 out of 83 tested batches contained less than 90%, none exceeded 110%. Conclusion In the four study countries, no falsified anthelminthic medicine was encountered. The active pharmaceutical ingredient was not found to either exceed or fall below specification limits. Galenic characteristics however, especially dissolution profiles, revealed great deficits.