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Teltayev B.B.,Kazakhstan Highway Research Institute | Amirbayev Y.D.,Kazakhstan Highway Research Institute
News of the National Academy of Sciences of the Republic of Kazakhstan, Series of Geology and Technical Sciences | Year: 2016

This paper investigates rheological characteristics (complex shear modulus, phase angle, stiffness, relaxation rate) of pure bitumen and polymer bitumens with the use of dynamic shear rheometer (DSR) and bending beam rheometer (BBR). Pure bitumen of grade BND 100/130 was produced by Pavlodar Oil Chemical Plant, and polymer bitumens were prepared by adding of polymers Elvaloy 4170 (1.4% of bitumen mass), Butonal NS 198 (3.0%) and Calprene 501 (4.0%) to pure bitumen in laboratory conditions. Before testing the binders were thermostated at testing temperatures for 10, 20, 30 and 40 hours. It was determined that at high temperatures (52, 58, 64°С) the additive of polymers increases essentially the complex shear modulus and decreases the phase angle of binders. In addition, polymer Calprene 501 showed maximum effect. For all testing temperatures the longevity of thermal condition does not practically affect on phase angle of bitumen binders. At negative temperatures (-24, -30, -36°С) the stiffness of binders is increased with temperature reduction and longevity of thermal conditions increase. Addition of polymer reduces essentially the stiffness of binders with longevity of thermal conditions up to 10 hours, and effect of modification with polymer disappears during longer-lasting thermal condition. The effect of modification of binders with polymer cannot be also found in relaxation rate at all testing temperatures and longevities of thermal condition. © National Academy of Sciences of the Republic of Kazakhstan, 2016.


Teltayev B.B.,Kazakhstan Highway Research Institute | Amirbayev Y.D.,Kazakhstan Highway Research Institute
News of the National Academy of Sciences of the Republic of Kazakhstan, Series of Geology and Technical Sciences | Year: 2017

Tensile strength of asphalt concretes and polymer asphalt concretes was determined experimentally at low temperatures through two methods in the paper. According to the first method the ends of the sample were fixed inflexibly. Temperature was reduced from +20°C with the rate of 10°C/h till sample damage. Critical stress and temperature were determined. According to the second method samples of asphalt and polymer asphalt concrete are deformed under the scheme of direct tension with constant rate (approximately 1 mm/min) at a constant temperature equal to -20°C till damage. The stress, when the damage of the sample occur (splitting into parts), has been admitted as the tensile strength of material. Prior to testing the samples were previously conditioned for 1, 10, 20, 30 and 40 hours. Test results showed that duration of preliminary conditioning impacts greatly on strength and deformability of asphalt and polymer asphalt concretes. During deformation with constant rate at -20°C tensile strength of all tested asphalt and asphalt concretes decreases with the increase of thermostatic conditioning duration up to 10 hours and further increase of duration does not impact practically on it. Meanwhile the strength decrease of asphalt concretes with bitumens grade BND 70/100 and BND 100/130, polymer asphalt concretes with polymers Elvaloy 4170, Calprene 501 and Butonal NS 198 is 49%, 32 %, 24 %, 25 % and 29 % respectively. During cooling with constant rate the duration of thermostatic conditioning does not impact practically on critical characteristics of asphalt concrete with bitumen grade BND 100/130 and polymer asphalt concrete with polymer Butonal NS 198. For other asphalt and polymer asphalt concretes the critical temperature is reduced with the duration increase of thermostatic conditioning, and critical stress increases. For all tested asphalt and polymer asphalt concretes the reduction of critical temperature at maximum thermostatic conditioning (40 h) is 2-2.5°C. Maximum increase of critical stress, which also complies with maximum duration of thermostatic conditioning (40 h), for asphalt concrete with bitumen grade BND 70/130, polymer asphalt concretes (BND 100/130 + Elvaloy 4170) and (BND 100/130 + Calprene 501) is equal to 28.0 %, 6.1 % and 15.0 % respectively. © National Academy of Sciences of the Republic of Kazakhstan, 2017.


Teltayev B.B.,Kazakhstan Highway Research Institute
News of the National Academy of Sciences of the Republic of Kazakhstan, Series of Geology and Technical Sciences | Year: 2017

This article shows test results of conventional hot mix asphalt and hot mix asphalt with polymers Kraton and Calprene for fatigue in a regime of controlled strain by the device of four-point bending with loading frequency of 10 Hz and temperature of 10 °C. Dissipated pseudo strain energy, connected with the increase of phase angle and reduce of complex modulus, as well as total dissipated pseudo strain energy were determined. Diagrams of dissipated strain energy changes were made depending on the number of loading cycles. Correlations were stated between the number of loading cycles to failure and constant strain of testing, between the number of loading cycles and total dissipated strain energy at failure. It was found that hot mix asphalt with polymer Calprene has the highest fatigue strength. © National Academy of Sciences of the Republic of Kazakhstan, 2017.


Teltayev B.,Kazakhstan Highway Research Institute | Aitbayev K.,Kazakhstan Highway Research Institute
Indian Geotechnical Journal | Year: 2015

The nonstationary temperature field is modeled by the finite element method. Results of the numerical analysis conform fully with the experimental data. By means of the developed finite element model, temperature variation has been obtained in points of asphalt concrete layers of pavement within one decade of the hottest period in the southern region of Kazakhstan. Using the solution of axisymmetric problem of elasticity theory for the layered media, stresses and deformations in specific points of flexible pavement under loading have been calculated at night period (when asphalt concrete layers temperature is minimum) and at day period (when asphalt concrete layers temperature is maximum). The obtained results showed that depending on temperature stresses and deformations in specific points of pavement change significantly. Therefore correct modeling of temperature field in flexible pavement is important in their designing. © 2014, Indian Geotechnical Society.


Teltayev B.,Kazakhstan Highway Research Institute
International Journal of Pavement Research and Technology | Year: 2015

In this paper a new criterion for determination of cycle number to failure of asphalt mixture at test in controlled strain mode is proposed. The proposed criterion is based on equality of total dissipated energy and total dissipated pseudo strain energy atfailure. The proposed failure criterion is presented in three forms: in energy balance form, in termsof linear viscoelasticity theory and continuum damage mechanics. A new criterion applicability is shown by testing of hot mix asphalt mixture samples on four point bending equipment in controlled strain mode. Comparison of loading cycle numbers to failureof asphalt mixture obtained using the proposed and other often used criteria are carried out. © Chinese Society of Pavement Engineering.


Teltayev B.,Kazakhstan Highway Research Institute
International Journal of Pavement Research and Technology | Year: 2014

Low temperature cracking is one of the prevalent types of hot mix asphalt pavement defects, and there are many methods of its evaluation. In this paper,the indicators of hot mix asphalt pavement low temperature cracking are evaluated by a combined approach, where hot mixasphalt tensile strength at low temperatures has been determined by testing in conditions of deformation with constant rate, and low temperature stress has been calculated based on integral equation of linear viscoelasticity theory. Conditions of aircooling have been considered throughthetemperature falling (cooling) rate. It has been ascertained that for the considered hot mix asphalt at cooling rate from 0.4°C/h to 1.6°C/h,Critical stress and Critical temperature do not depend on cooling rate: critical stress σcr=6.0to 6.2MPa, Critical temperature Тcr=-19to-21°C. The indicator, characterizing the low temperature stress increase rate in hot mix asphalt pavement, at Critical time also does not depend on the cooling rate and has constant value equal to 2.7. © Chinese Society of Pavement Engineering.


Teltayev B.B.,Kazakhstan Highway Research Institute | Aitbayev K.,Kazakhstan Highway Research Institute
Geomechanics and Engineering | Year: 2015

Mathematical model has been developed for determination of temperature field in multilayer pavement and subgrade, which considers transfer of heat by conduction and convection, receiving of heat from total solar radiation and atmosphere emission, output of heat due to the emission from the surface of pavement. The developed model has been realized by the finite element method for two dimensional problem using two dimensional second order finite element. Calculations for temperature field have been made with the programme realized on the standard mathematical package MATLAB. Accuracy of the developed model has been evaluated by comparison of temperatures, obtained theoretically and experimentally. The results of comparison showed high accuracy of the model. Long-term calculation (within three months) has been made in pavement points in accordance with the data of meteorological station for air temperature. Some regularities have been determined for variation of temperature field. © 2015 Techno-Press, Ltd.


Teltayev B.B.,Kazakhstan Highway Research Institute | Baibatyrov A.I.,Kazakhstan Highway Research Institute | Suppes E.A.,Kazakhstan Highway Research Institute
15th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, ARC 2015: New Innovations and Sustainability | Year: 2015

In 2010 temperature and moisture sensors were made and installed into the pavement and subgrade of the "Astana-Burabay" highway (North region of the Kazakhstan). In 2013 similar sensors were used for the "Atyrau-Aktobe" (West region) and "Almaty-Bishkek" (South region) highways. In the present paper the study results of subgrade frost penetration of the above stated highways are given. For each highway a subgrade frost penetration starting and finishing times are determined; frost penetration and thawing graphs are constructed; frost penetration and thawing rate values are determined; dependence of the amount of unfrozen water from the value of negative temperature and initial moisture is established.


Oliviero Rossi C.,University of Calabria | Spadafora A.,University of Calabria | Teltayev B.,Kazakhstan Highway Research Institute | Izmailova G.,Kazakhstan Highway Research Institute | And 2 more authors.
Colloids and Surfaces A: Physicochemical and Engineering Aspects | Year: 2015

Polymer modified bitumen (PMB) is used extensively in thin asphalt surfacing and seals in order to improve specific performances. However, the performances of PMB are not easy to demonstrate with the conventional methods, such as penetration test, softening point etc. In order to a better evaluation, different characterization methods are needed rather then ordinary empirical rheological tests. This work deals with the characterization of linear copolymer styrene-butadiene-styrene (SBS) and SBS+polyphosphoric acid (PPA) modified bitumen by using conventional as well as advanced methods on bitumens at different ageing steps and temperature. Fundamental rheological tests, based on a state of the art dynamic shear rheometer in the temperature range from -30°C to +160°C and advanced 1H magnetic resonance relaxometry analysis to evaluate the effect of modifiers on the bitumen structure, were used. Moreover, morphological analysis by scanning electron microscope (SEM) was performed on neat and modified bitumen and the effect of the filler addition on the supra-molecular organization of the bituminous binder was also investigated. © 2015 Elsevier B.V.

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