75 research outputs found

    Main flexible pavement and mix design methods in Europe and challenges for the development of an european method

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    Pavement and mix design represent one of the key components within the life cycle of a road infrastructure, with links to political, economic, technical, societal and environmental issues. Recent researches related to the characteristics of materials and associated behavior models both for materials and pavement, made it appropriate to consider updating current pavement design methods, and especially in the USA this has already been in process while in Europe uses of the methods developed in the early 1970s. Thus, this paper firstly presents a brief historical overview of pavement design methods, highlighting early limitations of old empirical methods. Afterwards, French, UK and Shell methods currently in use in Europe will be presented, underlining their main components in terms of methodology, traffic, climatic conditions and subgrade. The asphalt mix design and modeling in Europe are presented with their inclusion in the pavement design methods. Finally, the main challenges for the development of a European pavement design method are presented as well as the recent research developments that can be used for that methodThe second author would like to express the support of Portuguese National Funding Agency for Science, Research and Technology (FCT) through scholarship SFRH/BSAB/114415/ 2016. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.info:eu-repo/semantics/publishedVersio

    Development of Synbiotic Milk Chocolate Enriched with Lactobacillus paracasei, D-tagatose and Galactooligosaccharide

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    Background and Objective: Prebiotics are food ingredients that induce the growth or activity of beneficial bacteria (Bifidobacteria and Lactobacilli). Galactooligosaccharide and tagatose are two main prebiotic compounds which are used in the food industry. Chocolate is widely consumed all over the world and could be used as an excellent vehicle for delivery of prebiotics. Furthermore, the incorporation of probiotics into chocolate, allows broadening the health claims of chocolate. The aim of the current study was to investigate the effect of tagatose and galactooligosaccharide on the physicochemical and sensory properties of milk chocolate and the survivability of Lactobacillus paracasei in the optimized formulation. Material and Methods: Probiotic milk chocolate containing Lactobacillus paracasei were formulated by replacing a portion of the sucrose with the galactooligosaccharide powder and tagatose. For this purpose various concentrations of galactooligosaccharide and tagatose (2.5, 5 and 7.5% w w-1) along with stevia were used in chocolate formulation. Nine formulations were examined to determine some physicochemical, mechanical and sensory properties in order to find the optimum concentrations of these components. The lyophilized Lactobacillus paracasei were incorporated in the optimal formulation of prebiotic milk chocolate. The viability of probiotic bacteria in milk chocolate was carried out during storage at 22°C for up to 6 months.Results and Conclusion: In general, chocolate formulations with high levels of galactooligosaccharide, achieved the highest plastic viscosity and yield stress. The lowest viscosity and yield stress were observed for the samples containing high concentrations of tagatose and in control. In addition, galactooligosaccharide at higher ratios induced the least desirable sensorial effects, whereas tagatose improved the overall acceptability. It can be concluded that the overall acceptability of milk chocolate samples were with (7.5), tagatose: galactooligosaccharide ratios of 2.5%-2.5%, presenting the optimal applicable range as prebiotic compounds. Numbers of live Lactobacillus paracasei cells remained above 8.0 log CFU g-1 until 6 months under ambient conditions. Milk chocolate was shown to be an excellent vehicle for the delivery of Lactobacillus paracasei, and the prebiotic ingredients galactooligosaccharide and tagatose did not interfere in its viability. Conflict of interest: The authors declare no conflict of interest

    Quality Control of Field Asphalt Mixtures and Compatibility of Aggregates and Emulsions using Asphalt Compatibility Tester

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    The objectives of this project are to: (1) Establish a procedure to identify the optimum antistrip additive content for a given asphalt mixture and antistrip additive combination; (2) Evaluate the moisture damage resistance of plant-produced asphalt mixtures to establish a preliminary protocol for quality assurance and control; and (3) Develop an objective means to quantify emulsion- aggregate compatibility in lieu of the visual assessment procedure currently specified in NCDOT A-24 procedure. Laboratory- mixed, laboratory compacted mixtures were used to establish an antistrip dosage selection procedure for Boil test results coupled with Asphalt Compatibility Tester (ACT) color measurements
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