Analiza reologicznego zachowania drogowych kompozytów elastomerowo-asfaltowych poddanych próbie rozciągania w duktylometrze

The basic measurement method used to assess the properties of polymer modified bitumens is a tensile test. In this study, PMB specimens of various elastomer SBS content (in the range from 3% to 9%), but a similar penetration, determined at 25°C were tested. In order to evaluate the rheological properties and temperature susceptibility, the Force-Ductility Tests were conducted at 0, 10 and 25°C. On the basis of the obtained results, the values of the maximum force ratio (MFR) were calculated. It could characterize the efficiency of bitumen modification by elastomer addition. Moreover, on the basis of the first tensile force maximum determined at 0 and 25°C, values of the maximum force index (MFI) were calculated. This parameter may be an alternative to commonly used penetration index.Jedną z podstawowych metod pomiarowych stosowanych w celu oceny właściwości asfaltów modyfikowanych polimerami jest próba rozciągania. W niniejszej pracy badaniom poddano próbki kompozytów elastomerowo-asfaltowych o zróżnicowanej zawartości elastomeru SBS (w zakresie od 3% do 9%), ale o zbliżonej penetracji w temperaturze 25°C. W celu oceny właściwości reologicznych oraz wrażliwości termicznej lepiszcza asfaltowe wybrane do badań poddano próbie rozciągania z rejestracją siły w duktylometrze. Pomiary wykonano w temperaturze 0, 10 i 25°C. Na podstawie uzyskanych rezultatów wyznaczono wskaźnik maksimum siły (MFR), który można wykorzystać jako miarę efektywności modyfikacji asfaltów elastomerami. Ponadto, na podstawie wartości pierwszego maksimum siły rozciągającej oznaczonych w temperaturze 0 i 25°C obliczono indeks maksimum siły (MFI), który może stanowić alternatywę dla powszechnie stosowanego indeksu penetracji

Assessment of the Viscoelastic Properties of Modified Bitumens Containing Styrene-Butadiene-Styrene Copolymer

The viscoelastic behaviour of styrene-butadiene-styrene copolymer modified asphalt binders during tensile test and inverse creep test (retarded strain recovery after unloading) has been analysed in the presented paper. Laboratory tests have been conducted on two specimens of road bitumen: 20/30 and 50/70 penetration grade, which have been subjected to modification with the additive of 9% concentrate of SBS elastomer modified bitumen. When the two were mixed, the samples of polymer modified binders containing 3% or 6% by mass of the SBS elastomer were obtained. Force-ductility (tensile) test that has been followed by the extended procedure for the determination of elastic recovery, has been used as the research method. The results of the study have showed a significant improvement of the effect of modifications on the elastic properties and the temperature susceptibility reduction obtained only in the case of binders, where the polymer constitutes a dispersing phase forming a continuous network throughout the bitumen. Moreover, the temperature susceptibility coefficients, defined on the basis of the tensile test results, have been proposed as an alternative or extension to the previously widely used parameter, the Penetration Index

Modelling of the Inverse Creep of Road Bitumen Modified With SBS Copolymer

Polymer modified road bitumens, being examples of viscoelastic materials, are very interesting with respect to rheology. The phenomenon of inverse creep (retarded strain recovery) observed in samples of asphalt binders modified by the addition of SBS copolymer was analyzed in the present paper. Laboratory tests of strain recovery were conducted on samples of the three selected asphalt binders: the 50/70 penetration grade base bitumen and binders modified by the addition of 4% and 8% of the SBS copolymer. The extended procedure for the determination of elastic recovery was used as the research method. The results of the experiment were approximated using three linear viscoelastic rheological models: Burgers, Dual Kelvin+Newton and Dual Kelvin+Maxwell. When analyzing the results of modelling carried out by using the Burgers model it has been found that they were not satisfactory. Much greater compatibility of modelling and experiment results (R2 > 0.99) was achieved by using models containing the dual Kelvin element

Concrete pavements management

The article discusses the issue of managing roads with concrete surfaces. Modern methods of surface features identification applied on the exploited motorway section of a length of 100 km (in conversion to rows of concrete slabs it gives around 600 km) are presented. The general principles of the rigid surface management system are described below in order to enable a comprehensive analysis of the obtained data in terms of the possibility of developing concrete slabs degradation models that form the basis for long-term planning of maintenance works

An Experimental Study of the Impact of Aging on Gilsonite and Trinidad Epuré Modified Asphalt Binders Properties

The tests and analyses presented in the paper are related to the 20/30, 35/50 and 50/70 penetration grade road bitumens as well as the asphalt binders obtained through modification of the 35/50 and 50/70 bitumens. The latter were modified by adding to it 3%, 5% and 7% of the Gilsonite natural asphalt and 15%, 25% and 35% of the Trinidad Epuré Z 0/8 natural asphalt. The aim of the study was to assess the changes in the functional and rheological properties of the road bitumens that were modified by adding to them the Gilsonite and Trinidad Epuré natural asphalts. The modified asphalt binders were subjected to the laboratory simulated short-term and long-term aging, where two methods, designed as part of the Strategic Highway Research Program, were used, i.e. the Rolling Thin Film Oven Test and the Pressure Aging Vessel, respectively. The study of the asphalt binders both those that were subjected to aging and those unaged includes thermal susceptibility (the Penetration Index) and resistance to cracking at low temperatures by tests carried out using the Bending Beam Rheometer. The analysis of the results revealed that the unfavourable impact of the aging process on the asphalt binder properties is limited if a suitable amount of the natural asphalt is used as a modifier

Concrete pavements management

The article discusses the issue of managing roads with concrete surfaces. Modern methods of surface features identification applied on the exploited motorway section of a length of 100 km (in conversion to rows of concrete slabs it gives around 600 km) are presented. The general principles of the rigid surface management system are described below in order to enable a comprehensive analysis of the obtained data in terms of the possibility of developing concrete slabs degradation models that form the basis for long-term planning of maintenance works

Analiza lepkości zerowego ścinania (ZSV) asfaltów modyfikowanych kopolimerem SBS

The paper presents the results of the zero shear viscosity (ZSV) determined by using a dynamic shear rheometer (DSR). The tests were conducted with the use of 50/70 penetration grade bitumen produced from Venezuelan and Russian crude oils (named V50/70 and R50/70, respectively). Specimens of the tested polymer modified bitumens were combined with modified bitumen concentrate (containing 9% of SBS copolymer) by mixing them together. The objects of the tests were modified bitumens containing 1.5%; 3.0%; 4.5%; 6.0% and 9.0% of SBS copolymer. Zero shear viscosity (ZSV) was determined with the use of two methods: the creep method at various levels of shear stress in the time sequence and a method in which kinematic, sinusoidal angular deformation was applied. The tests were conducted at a constant temperature of 60˚C. The results of two ZSV tests gave similar findings for 50/70 penetration grade bitumen and modified bitumen with low SBS copolymer content (1.5%). In the case of modified bitumen with higher SBS copolymer content, i.e. 3%; 4.5%; 6%; 9%, zero shear viscosity determined by two methods gave different results.W pracy zaprezentowano wyniki oznaczeń lepkości zerowego ścinania (ZSV) wykonanych przy użyciu reometru dynamicznego ścinania (DSR). Badaniom poddano asfalty drogowe 50/70 pochodzące z dwóch różnych złóż ropy naftowej - rosyjskiej i wenezuelskiej. Asfalty modyfikowane uzyskano poprzez wymieszanie w/w asfaltów z koncentratem asfaltu modyfikowanego kopolimerem blokowym SBS (o stężeniu kopolimeru SBS równym 9%). Lepkość zerowego ścinania (ZSV) oznaczono dwiema metodami laboratoryjnymi: metodą pełzania przy stałym naprężeniu w zakresie od 10 Pa do 1000 Pa oraz metodą, w której zastosowano wymuszenie kinematyczne, sinusoidalne odkształcenie kątowe o stałej wartości amplitudy, o zmiennej częstości kątowej w zakresie od 100 rad/s do 0,1 rad/s. Badania zostały przeprowadzone w stałej temperaturze 60˚C. Lepkość zerowego ścinania (ZSV) oznaczona dwiema metodami dała zbliżone wartości dla asfaltów 50/70 niemodyfikowanych oraz niskomodyfikowanych (o zawartości kopolimeru SBS równej 1,5%). Uzyskane wartości lepkości zerowego ścinania dla asfaltów o większej zawartości kopolimeru SBS w asfalcie (zawartość kopolimeru 3,0%; 4,5%; 6,0%) dały zróżnicowane wyniki

Analysis of low temperature relaxation of natural asphalt modified road bitumens

W pracy przedstawiono rezultaty badań lepiszczy asfaltowych modyfikowanych dodatkiem asfaltów naturalnych Gilsonite i Trinidad Epuré oraz asfaltów drogowych 20/30, 35/50 i 50/70 przy zastosowaniu autorskiej metody obserwacji zjawiska relaksacji w niskiej temperaturze (–16°C) z wykorzystaniem duktylometru. Zjawisko relaksacji lepiszcza asfaltowego obserwowano przez 20 minut w warunkach stałego odkształcenia próbki asfaltowej wywołanego uprzednim jej rozciągnięciem ze stałą prędkością równą 1 mm/min. Zaobserwowano, że asfalty o większych wartościach penetracji charakteryzują się większą zdolnością do relaksacji (zmniejszenia naprężeń rozciągających) w niskiej temperaturze.The paper presents the results of research on asphalt binders modified with the addition of Gilsonite and Trinidad Epuré natural asphalts and 20/30, 35/50 and 50/70 penetration grade road bitumens using original method of observing the phenomenon of relaxation at low temperature (–16°C) with the use of a ducilometer. The asphalt binder relaxation phenomenon was observed for 20 minutes in the conditions of constant strain of the asphalt binder sample caused by its previous stretching with a constant speed equal to 1 mm/min. It was observed that binders characterized by higher values of penetration have a greater ability to relaxation (reducing tensile stress) at low temperatures

Ocena wpływu zawartości elastomeru styren-butadien-styren na właściwości funkcjonalne lepiszczy asfaltowych

This paper discusses the issue of improving the functional properties of road asphalt pavements by modifying bituminous binder with SBS copolymer. The main purpose of the paper is to assess the resistance to permanent deformations and the temperature susceptibility of polymer-modified road asphalt binders, which are most commonly used in the upper layers of road and airport pavements. The bitumens subject to the study originate from various crude oil deposits (Russian and Venezuelan). They were modified in laboratory conditions with a concentrated additive with the known content of the SBS copolymer of 9%. The result was a asphalt binder containing the known percentage of the SBS copolymer of 1.5%, 3.0%, 4.5% and 6%. The rheological properties of the tested bitumens were determined by use of a dynamic shear rheometer (DSR), and with the application of the sinusoidal variable load, in the broad test temperature spectrum (from 40°C to 100°C). The analysis of the values of the dynamic shear modulus |G*| of all the studied bitumens shows that the increase in the content of SBS copolymer in the tested binder increases the value of |G*|, which may result in higher resistance to permanent deformations of road pavements caused by repeated traffic loads, especially in the case of pavements operated at high temperatures. The asphalt mixtures resistance to rutting is one of the basic parameters related to road pavement service-life, affecting both the safety and driving comfort of users.Tematyka pracy związana jest z zagadnieniem polepszenia właściwości funkcjonalnych drogowych nawierzchni asfaltowych poprzez modyfikację lepiszcza asfaltowego kopolimerem SBS. Głównym celem pracy jest ocena odporności na odkształcenia trwałe oraz wrażliwości na zmiany temperatury asfaltów drogowych modyfikowanych polimerami, które są najczęściej używane w wierzchnich warstwach konstrukcji nawierzchni drogowych i lotniskowych. Przedmiotem badań były asfalty pochodzące z różnych złóż ropy naftowej (rosyjskiej i wenezuelskiej). Asfalty te poddano modyfikacji w warunkach laboratoryjnych z dodatkiem koncentratu o znanej zawartości kopolimeru SBS równej 9%. Otrzymano w ten sposób lepiszcza asfaltowe o znanej zawartości kopolimeru SBS równej 1,5%; 3,0%; 4,5% oraz 6%. Właściwości reologiczne badanych asfaltów oznaczono z użyciem reometru dynamicznego ścinania DSR stosując w testach obciążenie sinusoidalnie zmienne, w szerokim zakresie temperatury pomiarowej (od 40°C do 100°C). Analizując wartości dynamicznego modułu ścinania |G*| wszystkich badanych asfaltów można stwierdzić, iż wzrost zawartości kopolimeru SBS w badanym lepiszczu zwiększa wartość |G*|, co może skutkować większą odpornością na odkształcenia trwałe nawierzchni drogowej spowodowane wielokrotnie powtarzającymi się obciążeniami ruchem pojazdów, w szczególności w przypadku nawierzchni eksploatowanej w wysokiej temperaturze Odporność mieszanek mineralno-asfaltowych (MMA) na powstawanie kolein jest jednym z podstawowych parametrów związanych z eksploatacją nawierzchni drogowych, wpływając zarówno na bezpieczeństwo, jak i komfort jazdy użytkowników

Contactless approach to determine pavement skid resistance for Pavement Management System

Standard method to assess the pavement profile is to calculate the MPD (Mean Profile Depth) index based on results obtained usually by usage of laser techniques. In analysis the models of the surface pavements have been used in order to calculate the s1, s2, s3 parameters values corresponding to mega-, macro- and microtexture respectively. The values of the developed parameters s1, s2, s3 are calculated from the specific power spectral density values of surface roughness obtained for the threshold pavement roughness wavelength equal to 0.1, 0.05, 0.005 and 0.0005 m. The skid resistance has been correlated to the s1, s2, s3 parameters using 11 varied cases related to asphalt and concrete pavements. Skid resistance tests have been performed using CSR (Continuous Skid Resistance) device with fixed slip ratio equal to 13%. Three different test speed values 45, 65 and 95 km/h have been used. The obtained results lead to factorial correlation equations between developed parameters and skid resistance indices. Correlation results for uncontaminated pavement surface can be characterized by the coefficient of determination values in range between 0.55 and 0.94. The results can be used for contactless determination of pavement skid resistance in Pavement Management System