Time dependent viscoelastic rheological response of pure, modified and synthetic bituminous binders (original) (raw)
Related papers
Bitumen is predominantly used to construct pavements for roads, highways, and airports. Due to the viscoelasticity nature of bitumen, it plays a predominant role in the performance of the pavements where temperature and rate of load application have a great influence. In India, the specifications for bituminous binders rely on different empirical tests which have almost no significance on their performance characteristics are reported. In this paper, the physical and rheological properties of bituminous binders commonly used in India, at high and intermediate field temperatures are reported in terms of their performance characteristics. Considering several factors that affect the behavior of bituminous binders, the effects of variations in temperature, rate of loading and amount of loading are considered. The changes in the properties of commonly used grades of (60-70) bitumen both unmodified and modified with crumb rubber have been reported. The Marshall properties and indirect tensile strength ratio are compared for the specimens prepared at optimum binder content (OBC) for bituminous concrete (BC) grading-2. Crumb rubber modified bitumen shows higher Marshall Stability, reduced flow, higher ITS ratio and improved rheological properties in terms of rutting.
Influence of thermal history on rheological properties of various bitumen
Rheologica Acta, 2006
The mechanical properties of bituminous binders play an important role in the performance of the corresponding asphalt mix, and a lot of failure mechanisms in asphalt roads are believed to relate to a rheologcal aspect of the corresponding bituminous binder. In 1994, the strategic highway research program was the first to propose performance related specifications, which were based on rheological properties of the binders, taking into account the climatic and loading conditions of the pavement. Also, in the future European specifications, a lot of the tests will be based on rheological properties.
COMPARISON OF PHYSICAL AND RHEOLOGICAL PROPERTIES OF PLAIN AND CRUMB RUBBER MODIFIED BITUMEN
Bitumen is predominantly used to construct pavements for roads, highways, and airports. Due to the viscoelasticity nature of bitumen, it plays a predominant role in the performance of the pavements where temperature and rate of load application have a great influence. In India, the specifications for bituminous binders rely on different empirical tests which have almost no significance on their performance characteristics are reported. In this paper, the physical and rheological properties of bituminous binders commonly used in India, at high and intermediate field temperatures are reported in terms of their performance characteristics. Considering several factors that affect the behavior of bituminous binders, the effects of variations in temperature, rate of loading and amount of loading are considered. The changes in the properties of commonly used grades of (60-70) bitumen both unmodified and modified with crumb rubber have been reported. The Marshall properties and indirect tensile strength ratio are compared for the specimens prepared at optimum binder content (OBC) for bituminous concrete (BC) grading-2. Crumb rubber modified bitumen shows higher Marshall Stability, reduced flow, higher ITS ratio and improved rheological properties in terms of rutting.
Fuel, 2003
Traditional or technological studies about crumb tire rubber-modified bitumens (CTRMBs) do not provide detailed rheological information. In that way, this article describes the influence of processing conditions on the linear viscoelastic and viscous behaviors of CTRMBs. The results of the study reveal an exponential increase in dissolved/dispersed rubber with processing temperature and, therefore, lower solid content that affect the rheological behavior in different ways. No influence of the processing device was observed, probably due to the fact that processing temperature (1808C) was not high enough to break up the crosslinked network of the rubber. The presence of rubber particles avoids the negative hardening effects observed for unmodified bitumens, resulting in a more flexible binder at low temperature. At high in-service temperature, better rutting resistance would also be expected for CTRMBs. Flow results at 1358C indicates that modified bitumens can satisfy the AASHTO MP1 requirements if high-enough shear rates are reached. All the CTRMBs studied present segregation, due to rubber settling during storage at high temperature, although an increase in processing temperature seems to enhance its stability. The results obtained seem to indicate that the optimum CTRMB processing temperature is 2108C.
Polymers
This paper investigates the viscoelastic properties of oxidized neat bitumen and three polymer-modified binders at low temperatures. The earlier proposed interrelated expressions for the relaxation modulus and for the creep compliance of bitumen binders are further developed. The results of creep testing of the binders on a bending beam rheometer at the six temperatures from −18 °C to −36 °C are presented. The results were analyzed using the equations developed for the relaxation modulus and the relaxation time spectrum. Viscosities at the low temperatures of tested binders were estimated. Approximate interrelations between the loss modulus and the relaxation spectrum were presented. The method for the determination of the glass transition temperature of a binder in terms of the relaxation time spectrum is proposed. The glass transition temperatures of tested binders were determined by the proposed method and compared with ones determined by the standard loss modulus-peak method.
Synthesis of asphalt binders from renewable resources and their rheological properties
2007
At present, most adhesives and binders are mainly produced from petrochemicals and the fact that petroleum reserves are a finite resource means that in the future it may become necessary to produce these materials from renewable sources. Suitable resources may include polysaccharides, plant oils and proteins. This paper deals with the synthesis of polymer binders from monomers that could be produced from renewable resources. The aim has been to investigate if these synthetic binders show similar properties to bitumen so that future binders could be synthesised from renewable sources. Samples of poly(ethyl acrylate) (PEA) of different molecular weight, poly(methyl acrylate) (PMA) and poly(butyl acrylate) (PBA) were synthesised from ethyl acrylate, methyl acrylate and butyl acrylate, respectively, by atom transfer radical polymerization (ATRP). The fundamental rheological properties of these binders were tested by using a dynamic shear rheometer (DSR). The results indicate that PEA has rheological properties similar to that of 100/150 penetration grade bitumen, although 100/150 penetration grade bitumen is stiffer at ambient temperatures than PEA binder. At low temperatures, PEAs are softer than 100/150 penetration grade bitumen but have a greater elastic response compared to the more viscous response of the 100/150 penetration grade bitumen. High molecular weight PEA binders show better rheological properties than the low molecular weight PEA binders. However, PBA being highly viscous at room temperature cannot be used by itself as an asphalt binder but may be used to modify stiffer grade bitumen. PMA, on the other hand has similar rheological properties to that of 15 penetration grade bitumen at ambient temperatures but tends to be stiffer than the hard bitumen at temperatures greater than 60 C.
Performance-related and rheological characterisation of natural rubber modified bitumen
Construction and Building Materials, 2021
This paper is motivated by the limited research available evaluating the comprehensive effects of natural rubber bitumen modification (NR) for pavement applications. A detailed laboratory programme was carried out to evaluate the influence of NR on the high-intermediate-low temperature performance, including rheological characterisations and performance-related tests (fatigue cracking, thermal cracking, fracture and permanent deformation resistance). The main findings indicate some beneficial effects of NR on the performance-related response for fatigue and permanent deformation. Additional benefits were observed regarding the fracture strength and the thermal cracking resistance (ΔTc). The viscoelastic effects of NR produced significant changes in the rheological properties of the base bitumen. Overall, the use of NR at a concentration of up to 7% by weight of bitumen proved to be a reasonable option for use in pavement applications, having more substantial benefits in tropical regions in agreement with its predominant effects on the bitumen modification at intermediate-to-high temperature conditions.
Science Progress
Major distresses such as rutting, fatigue, and thermal cracking are facing asphalt pavement structures due to continuous heavy traffic loading and climate change. The modification of asphalt binders (one of the main components of the asphalt paving mix) has the potential to mitigate distresses through using different additives. Polymer modified asphalt (PMA) binders showed a noticeable resistance to pavement distresses as reported in previous studies. The present study aims to evaluate the effect of polymer modification on the rheological properties of asphalt binders through laboratory tests. The polymers included styrene-butadiene-styrene (SBS) and epolene emulsifiable (EE2) types. The 60/70 binder was used as a control for comparison. The Mechanistic-Empirical Pavement Design Guide (MEPDG) was also utilized to simulate the effect of PMA binders on the rheological properties under different climatic conditions and structural capacities. Additionally, the MEPDG was further utilized...
Influence of the thermal history on the rheological properties of modified 1 bitumens 2
2018
14 Due to the wide variation in geographic and climatic conditions, the growing demands of 15 resistant bituminous materials to various environmental conditions have resulted in a search for 16 bitumen modifiers capable to reduce the temperature susceptibility of the binder in the service 17 temperature range. Therefore, in the present contribution, the effects of addition of low 18 molecular weight organic compounds on temperature susceptibility of asphalt binders were 19 investigated by a combination of dynamics oscillatory rheology and Atomic Force Microscopy 20 (AFM). The results analyzed on the basis of weak gel model were found useful to discriminate 21 the selected additives regarding their relative capacity to favor coarse or fine colloidal 22 aggregates, which in turn were responsible for the observed bulk rheological behaviour. 23
Thermo-rheological behavior of modified bitumens adding virgin and waste polymers
The use of recycled polymers for replacing virgin polymers has been employed in the road building contributing to asphalt performance and lower environmental pollution. In this work the copolymers ethylene vinyl acetate (EVA) and a recycled EVA copolymer from industry (EVAR) were used as modifying agents of the Brazilian bitumen. Other additive as a cashew nut shell liquid (CNSL) was also added in order to evaluate its use as bitumen modifiers. The rheological properties of the modified binders were analyzed by means of dynamic shear rheometer (DSR) and accelerated ageing experiment (RTFOT). Differently to the original the modified binders showed non-Newtonian behavior. The results obtained reveal that EVAR can be considered as an interesting substitute of EVA not only as a mean of effecting improvement but also from an economic and environmental point of view. The use of the original EVA and EVAR waste polymers helped to improve the aging resistance. The rutting factor (G*/sin δ) suggest that the polymers and waste can improve the elasticity of the asphalt. The activation energy of the viscous flux (Ef) for the samples oscillated between 58 and 70 KJ/mo land showed that the additive CNSL can reduce the viscosity and thermal susceptibility of the modified binder.