The paper investigates the response of the pavement of a road sector analyzed to the traffic load that was determined numerically by using Abaqus numerical modelling software. This tool offers advanced analysis options in comparison with the normative road structure dimensioning tool. Thus, in contrast to the current use road structure dimensioning program, the FEM software allows the definition of the interfaces between layers and switch loads from static load to moving load, based on the determination of the resilient stresses and deformations in road structures by using the classical linear elastic multilayer model. The aim of this study was to determine whether the road pavement with deficiencies of adhesion between asphalt layers can take over the calculated traffic load considered in the study, or the proportion of design traffic load that can be taken over. That would allow an assessment of the service operation life of the road pavement and, implicitly, of the possibility of its yielding before the end of the perspective period considered.

The present paper presents a documentation on the realization of the dosages from recycled mixtures, highlighting the change in the test methods regarding the composition and the determination of the physical-mechanical characteristics according to the latest technical regulations. Practically, the structure of the new norm for cold recycled road materials aligns with the new European requirements in accordance with the provisions that the mixtures must meet, but still the problem remains on how to prepare the samples in the laboratory and determine the value of the stiffness modulus of the considered mixture, value which practically in the norm is considered based on good practice. Determining the real value of the stiffness modulus is a decisive factor in the dimensioning of the road structure reinforcement because it can considerably influence the thickness of the layers that make up the resistance structure. Therefore, the paper presents a study on the new methods of making samples in the laboratory and values of the stiffness modulus taken into account when dimensioning the reinforcement of road structures according to the composition of the considered materials.

This study focuses on the investigation of the effect of a reclaimed asphalt material (RAP) and a bio-rejuvenator (mix of vegetable oils) on the stiffness modulus and indirect tensile strength (ITS) values of eight bituminous mixtures produced by using three types of compaction, with different RAP amounts (25% and 50%) and rejuvenator (0%, 0.20%, 0.40% and 0.60% by mass of RAP). A conventional hot mix asphalt was considered as the reference mix. All tests were performed on cylindrical samples produced using: Marshall compaction with 50 blows/side, cored cylindrical specimens from slabs compacted using a roller compactor (39 passes), and, respectively, gyratory compaction on 80 gyrations. Stiffness modulus and ITS values showed strong linear variation with the increase in rejuvenator content, independently of test temperature and type of compaction. The rejuvenating effect of the bio-rejuvenator was observed to counterbalance the impact of RAP. The results at 20 °C for gyratory specimens for the mix with 50% RAP and 0.40% bio-rejuvenator were comparable/closer (under 5% relative difference) to those obtained for the reference mix. A strong correlation between stiffness modulus values of mixes and penetration values of the corresponding binder blends was obtained (R2≥0.977).

This article investigates the response of the road pavement of a road sector analysed to the action of traffic that was determined numerically by using two dedicated software. In this respect, the Romanian program CALDEROM 2000 (PD 177, 2001), respectively the French program for calculating the road pavements ALIZÉ-LCPC were used. Both programs use the Burminster elastic model for the analytical evaluation of stress states and specific deformations in multilayer road pavements. However, unlike the CALDEROM 2000 program, the ALIZÉ-LCPC software allows the user to define the interfaces between layers and switch loads from single axle to multiple loads, being a rational method, based on the determination of the resilient stresses and deformations in road structures by using the classical linear elastic multilayer model. The aim of this study was to determine whether the road pavement with deficiencies of adhesion between layers is able to take over the calculated traffic considered in the project, possibly the proportion of calculation traffic that can be taken over, which would allow an assessment of the capable operation life of the road pavement and, implicitly, of the possibility of its yielding before the end of the perspective period considered.

The purpose of this paper is to perform an analysis regarding the choice of a method for designing a dosage of an asphalt mixture. There have been concerns in the field of asphalt mix dosing since 1920 when Field and Hubbard introduced the impact compaction with the Proctor hammer for laboratory testing. Later, Marshall introduced the method that bears his name and which remained the most used method for determining the asphalt mixture dosages in Romania. Since it was found that the density of the samples obtained in the laboratory did not correspond to the density of the cores extracted from the compacted asphalt layers, the gyratory compaction was introduced, which is now frequently applied in the USA and other European countries. The study presented in this paper deals with the problem of establishing the mixture of aggregates, filler and binder in terms of the volumetric method (Superpave) and Marshall method, presenting both theoretically and experimentally the dosage study of an asphalt mixture type BA16 (asphalt concrete with maximum grain size of 16 mm) but also the physical-mechanical characteristics obtained following the application of the two methods for determining the dosage for the studied BA 16 type asphalt mixture.

The purpose of this study was to evaluate the influence of anti-stripping green additives on the behaviour of a fresh binder. Firstly, the adhesiveness (spectrophotometric method) and affinity (rolling bottles method) of a binder with a penetration grade of 50/70 on two types of aggregates (natural quarry aggregates from two different sources) were investigated. The results show a weak bond and stripping between the 50/70 binder and the aggregates. Therefore, two different anti-stripping green additives (named A and B) were used in three percentages. A total of six blends were tested to establish the optimal content of the additive by performing a series of conventional tests combined with the adhesiveness test and the affinity test. Finally, the rheological behaviour of the optimal blends and of the fresh binder was investigated by performing DSR tests. The 0.4% dosage of green additive B was considered the most effective due to the fact that this dosage did not have a significant influence on the conventional properties and rheological behaviour of the 50/70 binder but had a major impact on the adhesiveness (15% increase), affinity after 6 h (13% increase), and affinity after 24 h (25% increase).

As the traffic increases in urban areas, the noise generated by the vehicles has become a major concern during the last decade and many countries have been looking for solutions to reduce the level of disturbance. The lowering of the noise level by choosing the correct type of asphalt mixture may be considered as an alternative to sound-absorbing walls. The use of these low-noise asphalt mixtures requires a previous verification of the technical conditions and the performance levels they need to meet. The paper presents the research and laboratory tests aimed at comparing the physicalmechanical characteristics of a maximum 16mm grain size bituminous concrete (BA16) with a low-noise bituminous concrete used in the wearing course of bituminous pavements. This research started from the fact that the Romanian design standard for asphalt mixtures does not stipulate the physical-mechanical characteristics required by a low-noise asphalt mixture. Thus, in order to clarify this matter, the physical-mechanical characteristics of a 16mm grain size laboratory-made bituminous concrete (BA16) were compared to the characteristics of a low-noise asphalt mixture presented by the specialized literature. The results obtained following laboratory testing of the asphalt concrete and the research of the specialized literature concerning low-noise asphalt mixtures confirm the differences as far as their physical-mechanical characteristics are concerned (voids, bulk density, dry density, Marshall stability and flow and stiffness modulus).

The objective of this article was to investigate the influence of a rejuvenator of vegetal origin on the behavior of several binder blends at low and high temperatures. An important characteristic of a binder is the critical temperatures that are related to the pavement performance (its susceptibility to temperature change). One fresh binder (50/70 penetration grade binder), a Reclaimed Asphalt Pavement (RAP) binder, and a rejuvenator were blended in different dosages, and a total of 17 binders were tested. Complex shear modulus tests at high and intermediate temperatures and bending beam rheometer tests at low temperatures were performed in order to obtain the critical temperatures. Another objective was to estimate T, D, S, R, h, i, g, h, c, r, i, t, i, c, a, l, , , , , , and T, B, B, R, l, o, w, c, r, i, t, i, c, a, l, , , , , , for all blends from the experimental results of base constituents by using two estimation approaches (a classical and a proposed approach, which is an original input of this work). A statistical analysis was performed in order to highlight their validity. Good correlation was found between the experimental and the estimated results. However, a more accurate estimation was performed with the proposed approach that has the great advantage of requiring only the temperature values and concentrations (a,b,c) for the three base components (respectively, fresh binder, RAP binder, and rejuvenator).

The paper focuses on the investigation of the potential environmental impact related to the production of several types of bituminous mixtures containing different dosages of Reclaimed Asphalt Pavement (RAP) and Rejuvenator (Rej). All materials used in the presented study are specific and generally used for pavements in Romania. The RAP material was considered as an inert material and it was used in three dosages (25%, 50% and 75%). For the bituminous mixture produced with 50% RAP material, a rejuvenator consisting in a mixture of vegetal oils was used in three dosages of 0.2%, 0.4% and 0.6% by mass of RAP material. A total of seven types of bituminous mixtures were considered including one ‘conventional’ mixture produced with virgin materials and used as reference. The Environmental Impact Assessment was estimated for the production process of the analysed bituminous mixtures, by using Eco-indicator 99 method within SimaPro software. The results prove that the addition of RAP material leads to a net decrease of the energy use and environmental impact. Besides, when rejuvenators are used in this process, they can affect the energy balance and reduce the difference in environmental impact.

The first objective of this study is to highlight the effect of the rejuvenator on the linear viscoelastic (LVE) properties of various blends of a fresh 50/70 binder and a reclaimed asphalt pavement (RAP) binder, with a rejuvenator (a mixture of vegetal oils). A total of 17 binders (including pure fresh and RAP binders) produced as blends of two base binders and a rejuvenator in various proportions were tested. Dynamic shear rheometer tests were performed, and the experimental results were modelled using the 2S2P1D model. The second main objective was to present and analyse two different approaches for estimation of 2S2P1D parameters and temperature shift factors of binder blends, based on reduced experimental data (only data for the base constituents). Good correlation was found between the direct determination and the estimated results. However, a more accurate estimation was performed with the second approach.

This paper focuses on the influence of the RAP-extracted binder and rejuvenator contents on the steady shear viscosity obtained as a linear viscoelastic property of different binder blends. One pure fresh 50/70 binder, a RAP-extracted binder and a rejuvenator of vegetal origin were mixed in different dosages. Steady shear viscosity (eta(0)) values at different temperatures (from 25 degrees C to 85 degrees C) were determined from complex shear modulus results for all tested binders. In addition, eta(0) (T) values of all binder blends were estimated from eta(0) (T) values of base constituents by using two different approaches. Good correspondences with experimental results were found. (C) 2020 Elsevier Ltd. All rights reserved.

The linear viscoelastic behavior of various blends of a fresh binder (a straight-run 50/70 penetration grade binder) and a RAP-extracted binder, with and without rejuvenator (a mixture of vegetal oils), was studied. The experimental plan includes a total of 9 binders: fresh binder, RAP binder, 3 blends of RAP binder and rejuvenator and 4 blends of fresh and RAP binders with and without rejuvenator. The rejuvenator content used for blends was 0

The properties of various blends of a fresh binder (50/70 penetration grade) and a RAP-extracted binder, with and without a rejuvenator, were studied. A mixture of vegetal oils was used as rejuvenator in different dosages. A total of 17 binders were tested, including pure fresh and RAP binders. Conventional tests were performed in order to determine penetration at 25 degrees C, softening point (T-R&B), Fraass breaking point (T-Fraass). ductility (elongation at 25 degrees C) and density at 25 degrees C. The steady-shear viscosity (eta(0)) of all binders was calculated from complex modulus test results. Two different approaches were proposed in order to estimate values of penetration, T-R&B, T-Frsass, and eta(0) of blends from properties of base constituents. Excellent correspondences with experimental results were observed. (C) 2019 Elsevier Ltd. All rights reserved.

The rheological behaviour of various blends of a fresh binder (50/70 penetration grade) and a RAP-extracted binder, with and without regenerating agent, was studied. A mixture of vegetal oils was used as regenerating agent in different dosages (0%, 5%, 10% and 15% by mass of RAP binder). The RAP binder content used for blends was calculated in order to reproduce the exact amount of RAP binder within a mixture containing 50% of RAP material, according to its binder content. A total of 6 binders were tested, including 4 blends (corresponding to 4 regenerating agent contents) and pure fresh and RAP binders. Penetration, softening point and elongation tests were performed. Rheological behaviour was characterized in terms of complex shear modulus by means of Dynamic Shear Rheometer (DSR) tests. The steady-shear viscosity of all binders was calculated from complex modulus test results and its relation with penetration was studied.

Due to the large volume of torrential rainfall, of surface water seepage on the slopes of the mountains and the raise of the Susara River, the water altered the stability of the slopes and the neighboring river banks. The phenomenon resulted in partial collapses of the retaining walls within the built-up area, which damage the village roads, and sliding actions of partially caved-in masonry elements which used to be supporting elements which had ensured the protection of the banks of the Susara River.In this context, the paper aims at presenting several efficient solutions and measures to be taken in order to restore the safety of the built-up area of the Sasca Montana village in the Caras-Severin County.