Explore the vast range of titles available.

In this study, the experimental and numerical effects of using waste glass as aggregates of asphalt pavement are evaluated. The main reason for using this waste material as aggregates of hot mix asphalt (HMA) is to alleviate an environmental problem associated with asphalt pavements called urban heat islands. This phenomenon can increase the temperature in urban areas compared to their suburbs. Regarding the experimental part, two different HMA mixtures containing 100% limestone aggregates (HMAL) and 100% glass aggregates (HMAG) are made in this study. An experimental setup is used to simulate the solar radiations on top of HMA specimens. As a result, thermal parameters, including thermal conductivity, thermal diffusivity, and specific heat capacity, are measured and calculated using the heat transfer equations and the heat transfer test. These results are then used to develop finite element models for two different pavement structures with different asphalt concrete layers (one of them with HMAL and the other with HMAG). Furthermore, the air temperature data, extracted by TRNSYS software for Bechar city in Algeria, are used for modeling. The surface temperature, first and second temperatures in the asphalt pavement are obtained. The results revealed that using this waste aggregate increased the surface temperature during the day, which can make it susceptible to rutting. However, it reduced the surface temperature at night. More importantly, the HMAL absorbs 34% and released 47% more heat than HMAG during days and nights. Hence, the HMAG performance can mitigate the UHI effects. Moreover, using this waste material as aggregates in HMA can introduce a recycling method with low costs.

Construction and demolition waste (CDW) materials account for a considerable part of waste materials throughout the world. As these materials are not usually recycled, reusing them in construction projects is of major significance. In this study, recycled concrete, bricks, and glass were used as 100% aggregates of chip seal, which is a corrective or preventive pavement maintenance method. A cationic rapid setting (CRS-2) bitumen emulsion was also used to prepare the chip seal. Different tests, including the sand patch test, sweep test, British pendulum tester (BPT), interface bond, and Vialit test, were conducted. The results of these tests revealed that all these materials had sufficient aggregate embedment for vehicle speeds of more than 70 km/h, and the number of chips was less than 10%, indicating their good performance. All developed chip seals ranked as high skid resistance pavement at ambient temperature. The chip seals developed with concrete and glass showed the best adhesion with an asphalt pavement surface and an aggregate–bitumen adhesion at very cold and ambient temperatures due to the fact of their chemical compositions. Overall, using concrete aggregates to develop chip seals under different traffic loads is recommended. Finally, these findings can provide a novel approach for recycling CDW materials with low costs.

With the increased knowledge of sustainable pavement construction, recycled materials more and more are being used in roadwork applications, especially as base materials. Among various recycled materials, recycled glass aggregate is of the special attraction in the present study. The main goal of this investigation is evaluating the behavior of base course containing recycled glass using resilient modulus (Mr) from laboratory testing. In this regard, recycled glass (RG) is replaced the same range size of the local base course material (MG20) based on volumetric method. The studied RG aggregate was in the range size of 0–5 mm. The results revealed that as RG content increased, Mr values of blends decreased. Furthermore, the shear strength of blends followed the similar trend as it decreases by RG contents. Finally, based on the experimental observation a model was proposed to interpret the effects of RG on the resilient modulus values of blends. Conclusively, using RG up to 25% of MG20 may change the growing trend of environmental problems, in a green way, without significant effects on the mechanical behavior.

This project aims to evaluate the effects of changes in the correlation length of the rigidity of the subgrade flexible pavement roughness expressed in terms of the International Roughness Index (IRI). The correlation length, which defines the structure of the dispersion of soil rigidity, has a direct effect on the wavelength of the induced deformations, and thus the value of the IRI. The IRI is evaluated from pseudo-profiles decomposed according to specific wavelengths. It aims: (1) to show, according to a numerical and statistical approach, the influence of the inherent spatial variability of soil properties on the road in terms of stress and displacement, and (2) to analyze the effects of ground deformation on the values of the IRI.

In order to get the most out data from a pseudo-profile and to further develop an international roughness index (IRI) concept, a new interpretation approach of the IRI is presented. It is based on the breakdown of the initial pseudo-profile of a pavement into elementary pseudo-profiles based on various well-defined wavelengths. The underlying hypothesis to this approach is that the IRI calculated on these elementary pseudo-profiles is proportional to the contribution of each one to pavement condition. From this hypothesis, various pseudo-profile analytical techniques are presented. A few definitions and context are presented first. The following approach is then described: (i) filtering technique, (ii) calculation of the IRI for elementary pseudo-profiles, (iii) additional analytical tools. Finally, an application example describes the approach.Key words: IRI, filtering, pseudo-profile, pavement, defect, wavelength, bandwidth, profilometre, evenness.[Journal Translation]

In an attempt to apply the concepts developed by Carman and Klinkenberg for the measurement of permeability of a porous media using a gas, a permeameter for the in-situ measurement of intrinsic permeability of skin concrete has been developed. The established technique allows concentration of gas percolation through a well-defined zone in the superficial layer of concrete. The instrument, the measurement method, and the calculation procedure are described in details in this paper. Several series of tests have been performed in laboratory on concrete blocks (300 × 300 × 400 mm) to simulate measurements on the construction site. Three types of concrete, with different porosity, have been tested. The measurement of permeability performed on the concrete blocks have been accomplished both on shaped surfaces, which are representative of skin concrete, and on sawed surfaces, which are representative of mass concrete. Results show that the relationship between the water/cement ratio and the permeability of skin concrete varies distinctively compared with that of mass concrete. The permeameter allows quantification of what has been for a long time qualified as a determining element in terms of the durability of concrete against the corrosion of reinforcement, that is, the distinct permeability of skin concrete from that of mass concrete.Key words: skin concrete, in-situ permeability, intrinsic permeability, apparent permeability, permeameter, Klinkenberg.[Journal translation]

In order to get the most out data from a pseudo-profile and to further develop an international roughness index (IRI) concept, a new interpretation approach of the IRI is presented. It is based on the breakdown of the initial pseudo-profile of a pavement into elementary pseudo-profiles based on various well-defined wavelengths. The underlying hypothesis to this approach is that the IRI calculated on these elementary pseudo-profiles is proportional to the contribution of each one to pavement condition. From this hypothesis, various pseudo-profile analytical techniques are presented. A few definitions and context are presented first. The following approach is then described: (i) filtering technique, (ii) calculation of the IRI for elementary pseudo-profiles, (iii) additional analytical tools. Finally, an application example describes the approach.Key words: IRI, filtering, pseudo-profile, pavement, defect, wavelength, bandwidth, profilometre, evenness.[Journal Translation]

In an attempt to apply the concepts developed by Carman and Klinkenberg for the measurement of permeability of a porous media using a gas, a permeameter for the in-situ measurement of intrinsic permeability of skin concrete has been developed. The established technique allows concentration of gas percolation through a well-defined zone in the superficial layer of concrete. The instrument, the measurement method, and the calculation procedure are described in details in this paper. Several series of tests have been performed in laboratory on concrete blocks (300 × 300 × 400 mm) to simulate measurements on the construction site. Three types of concrete, with different porosity, have been tested. The measurement of permeability performed on the concrete blocks have been accomplished both on shaped surfaces, which are representative of skin concrete, and on sawed surfaces, which are representative of mass concrete. Results show that the relationship between the water/cement ratio and the permeability of skin concrete varies distinctively compared with that of mass concrete. The permeameter allows quantification of what has been for a long time qualified as a determining element in terms of the durability of concrete against the corrosion of reinforcement, that is, the distinct permeability of skin concrete from that of mass concrete.Key words: skin concrete, in-situ permeability, intrinsic permeability, apparent permeability, permeameter, Klinkenberg.[Journal translation]

The Global Environmental Multiscale (GEM) model is the Canadian atmospheric model used for meteorological forecasting at all scales. A limited-area version now also exists. It is a gridpoint model with an implicit semi-Lagrangian iterative space–time integration scheme. In the “horizontal,” the equations are written in spherical coordinates with the traditional shallow atmosphere approximations and are discretized on an Arakawa C grid. In the “vertical,” the equations were originally defined using a hydrostatic-pressure coordinate and discretized on a regular (unstaggered) grid, a configuration found to be particularly susceptible to noise. Among the possible alternatives, the Charney–Phillips grid, with its unique characteristics, and, as the vertical coordinate, log-hydrostatic pressure are adopted. In this paper, an attempt is made to justify these two choices on theoretical grounds. The resulting equations and their vertical discretization are described and the solution method of what is forming the new dynamical core of GEM is presented, focusing on these two aspects.

Accurately representing model-based sources of uncertainty is essential for the development of reliable ensemble prediction systems for NWP applications. Uncertainties in discretizations, algorithmic approximations, and diabatic and unresolved processes combine to influence forecast skill in a flow-dependent way. An emerging approach designed to provide a process-level representation of these potential error sources, stochastically perturbed parameterizations (SPP), is introduced into the Canadian operational Global Ensemble Prediction System. This implementation extends the SPP technique beyond its typical application to free parameters in the physics suite by sampling uncertainty both within the dynamical core and at the formulation level using “error models” when multiple physical closures are available. Because SPP perturbs components within the model, internal consistency is ensured and conservation properties are not affected. The full SPP scheme is shown to increase ensemble spread to keep pace with error growth on a global scale. The sensitivity of the ensemble to each independently perturbed “element” is then assessed, with those responsible for the bulk of the response analyzed in more detail. Perturbations to surface exchange coefficients and the turbulent mixing length have a leading impact on near-surface statistics. Aloft, a tropically focused error model representing uncertainty in the advection scheme is found to initiate growing perturbations on the subtropical jet that lead to forecast improvements at higher latitudes. The results of Part I suggest that SPP has the potential to serve as a reliable representation of model uncertainty for ensemble NWP applications.