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Asphalt mastic is known to play an important role when determining the fatigue performance of asphalt mixture. Time sweep test using a Dynamic Shear Rheometer can be used. However, a long testing t...

A laboratory study was done on three bitumen of penetration grade 50/70 from three sources and three corresponding mastics made using these three base bitumen and one filler – Limestone. The tests ...

Introduction. Transport times of hot asphalt from its production facility to the road section of laying depends of the distance of the asphalt mixing plants location, also in urban conditions it depends from the intensity of traffic flows, the number of traffic jams on the way of the dump truck.Problems. At the present stage, a sharp decrease of road pavement quality and durability occurs due to an increase of the number of heavy vehicles, an increase of axle loads on the pavement and an increase in the speed limit, due to use of outdated technologies that not correspond to the existing loads by their technical characteristics.Purpose. To analyze the modern technology of crushed stone — mastic asphalt transportation in order to determine the shortcomings in its application.Materials and methods. Analysis of information sources, including foreign sources regarding transportation technologiesResults.Possible consequences of non-observance of the correct transportation technology and their elimination have been determined.Conclusions. During the transportation of crushed stone — mastic asphalt mixture, the temperature and fractional segregation (dissection) of the hot mixture occurs. The main factors that cause it are following: ambient temperature, air humidity, wind speed, bulk filling, transport times, pavement flatness during transportation. To prevent the segregation appearance, it is need to increase the loading rate of the dump truck bulk, using heat-insulating elements during transportation (awnings, metal covers, etc.), also as thorough cleaning of the dump truck bulk surface from any residuals of bituminous and other materials before each loading of crushed stone-mastic asphalt.Keywords: crushed stone-mastic asphalt, temperature segregation, transportation technology.

Rutting is an important problem in Russia today. One of the ways to improve the properties of asphalt concrete mixtures and reduce wear on road surfaces is to modify the binder with polymer additives. The aim of the work was to test the selected compositions of MMAC mixtures containing bitumen modified with the addition of sevilene and rubber for rutting resistance, which make it possible to predict the formation of plastic rut. It was revealed that when using sevilen in its composition, with an increase in the concentration of vinyl acetate, the depth of the track increases in comparison with the industrial polymer-bitumen binder. It is shown that with the introduction of a complex additive based on sevilen and rubber into the binder composition, its rutting decreases and the service life of the road surface increases, which indicates a high elasticity of the complex-modified binder. In this work, the calculation of the service life of the coating before the formation of a critical rut requiring repair of the coating is carried out. It was found that in terms of the slope of the rutting curve and the proportional depth of the rut, the compositions with sevilene and rubber are not inferior to traditional industrial PBB.

The 55-km-long Hong Kong–Zhuhai–Macao Bridge (HZMB) is the world’s longest sea-crossing bridge, connecting Hong Kong with Zhuhai and Macao at the mouth of the Pearl River Estuary in China, comprising 22.9-km-long steel bridges. HZMB is the leading steel bridge in China, with top-level manufacturing and installation technology. This paper outlines the steel bridge construction experiences of HZMB to provide comparisons for the construction of other long sea-crossing steel bridges at home or abroad. The main considerations of construction constraints, scheme selection, structural and aesthetic design of HZMB are presented, and the following points related to new strategies in the steel bridge construction of HZMB are elaborated: (1) construction quality assurance, (2) automatic manufacturing technology, (3) large segment offshore installation, (4) eco-friendly paint (content limitation of volatile organic compounds) and new multifunctional inspection gantry, and (5) Guss Mastic Asphalt steel deck pavement system. The successful implementation of those strategies shows that the steel bridge construction of HZMB promotes improvement in the overall construction and management level of the Chinese bridge industry. The advanced experience of HZMB has opened up broad prospects for the design and construction of offshore bridge engineering in China.

Utilisation of recycled construction and demolition waste (CDW) within pavements is a beneficial substitution technique towards sustainability. Following this approach, this research investigates t...

One of the main reasons for reducing the service life of road asphalt pavements (the appearance and development of damage in the form of ruts, various kinds of plastic deformations, potholes, cracks, etc.) is the low quality of the used oil bitumen. The physicomechanical properties of road bitumen are subject to stricter requirements, especially for organic binders used for the production of crushed stone mastic asphalt (SMA), therefore, in authors’ view, the development of bitumen binders with enhanced physicomechanical properties is one of the key and most urgent tasks in road construction. This problem is solved by introducing various modifiers into the binder. This article presents the results of a study of bitumen modified by introducing technical sulfur into the composition. The effect of binder modification on the physicomechanical properties of road asphalt concrete is shown on the example of crushed stone mastic asphalt (SMA-20) relative to base samples made to control the dynamics of changes in the properties of composites made using sulfur-raising technologies. For a comprehensive assessment of the effectiveness of modifying crushed stone mastic asphalt concrete based on various binders, a generalized quality criterion is calculated, taking into account the calculated particular quality criteria and various values of the weight coefficients. The comparison and analysis of the obtained efficiency criteria is made.

Mastic asphalt is a type of pavement material that has good fluidity and is self-levelling at construction temperature for the bridge deck. There are highly accurate methods and indexes for evaluating fluidity and high-temperature deformation resistance for mastic asphalt-design and construction-control systems. The fatigue cracking is one of the main failure forms of bridge deck pavement. Therefore, the method used to evaluate the fatigue properties of pavement materials is also essential. The anti-deformation capability of the mastic asphalt must be increased, that results in poor fatigue performance and consequent failure of the bridge deck pavement to avoid the rutting of bridge deck pavement. In this study, a simple method is put forward for evaluating mastic asphalt fatigue performance. Impact toughness is defined as the area under the load-displacement curve of a three-point bending beam specimen under impact load to evaluate the fatigue performance of mastic asphalt. The four-point bending beam fatigue test is used to verify the rationality of the impact toughness test method. The results showed that there is a good correlation between the impacts toughness index of mastic asphalt produced under different mixing conditions and the accumulative dissipative energy and fatigue life demonstrated by the four-point bending beam test. Therefore, to evaluate the fatigue performance of mastic asphalt by impact toughness test. Fatigue performance and rut resistance are two ways to evaluate road performance of asphalt mixtures, but they are mutually restrictive. The results show that impact toughness and dynamic stability are inversely correlated. As the impact toughness increases, dynamic stability decreases. Therefore, balancing the fatigue performance and high-temperature rutting resistance of mastic asphalt in the design and quality control is very important.

High-quality and durable asphalt pavement ensures safe and comfortable traffic, optimal logistics costs, territory attractiveness to construction investments, and industrial development. With constantly increasing loads on road pavements, it is necessary to improve the asphalt quality by introducing additives into the mixture, design methodology, scientific justification for the selection and preparation of raw materials. The paper proposes the development algorithm of crushed-stone and mastic asphalt modified by the new stabilizing additive, which consists of 90 % of cellulose fiber from waste paper, 5 % rubber powder, and 5 % bitumen. The optimal particle size distribution of the mineral component in the crushed-stone and mastic asphalt is considered to be 73% of crushed stone with fractions of 15–20, 10–15 and 5–10 mm, 16 % of dolomite sand from crushing screenings, 11 % of mineral powder, 0.4 % of stabilizing additive and 5.5 % of bitumen. The compressive strength of the developed composition is 2.3 times higher than that meeting the requirements of GOST 31015–2002 for the climatic zone II. The research results are confirmed by pilot-industrial tests in constructing the road pavement in Tyumen.

The present study was carried out to evaluate effects of regular sized hydrated lime (RHL) and Nano-sized hydrated lime (NHL) on rutting resistance performance of asphalt mastic related to stiffnes...

The long-term effects of SBS-modified binders and rejuvenators on the properties of high-RAP mixtures, especially the cracking resistance, have not been resolved. Therefore, this paper evaluates th...

Reclaimed asphalt pavement (RAP) arises from the demolition of asphalt road layers. The Optimal Recycling of Reclaimed Asphalt Pavements Project concerns the cold recycling of 100 % RAP without binder addition in base and subbase layers of low-traffic roads. In this context, a test program was performed with Rhine region materials to evaluate the impact of the mastic coating of untreated RAP. A source of reclaimed asphalts with 4.4 % of bitumen is tested before (RAP) and after binder extraction (RAP-BE) and then is compared to an unbound granular material (UGM) with a similar particle-size distribution. Repeated load triaxial tests were conducted at several frequencies to study the permanent and resilient behaviors. The results show that the RAP before binder extraction and the UGM present similar permanent behaviors, while the aggregates without binder reveal low strains. Concerning the resilient phase, the RAP and the RAP-BE show similar levels of strains, but the resilient moduli of the UGM are significantly lower than those of the RAP. From the experimental results, the nonlinear elastic Boyce model was fitted and brings out a highly anisotropic mechanical behavior of the RAP. Finally, the RAP shows a frequency-sensitive viscous behavior because of the bitumen in the mastic, while the effect of the frequency is negligible for the RAP-BE.

Viscoelastic characterisation of asphalt mixtures is an important component for modelling and performance prediction of flexible pavements. In this study, using spherical indentation testing for measuring the viscoelastic properties of asphalt is explored. Indentation testing may provide an interesting alternative to existing experimental techniques, as it is capable of characterising small material volumes. Thus, it may become a useful tool for the characterisation of thin asphalt layers and for the measurement of binder phase properties in-situ in asphalt mixtures. Spherical indentation tests are performed on two mastic asphalt (MA) mixtures, prepared with different mastic types. The shear relaxation moduli obtained from the indentation tests are compared with the ones measured with seismic and SuperPave Indirect Tensile (IDT) tests. A new statistical analysis methodology is proposed for viscoelastic characterisation of the mastic phase with the indentation tests performed on MA mixtures. The accuracy and sensitivity of the developed method are examined. QC 20211110

The present study evaluates effects of regular sized hydrated lime (RHL) and nano sized hydrated lime (NHL) on fatigue and bond strength of asphalt mastic. The asphalt mastics were produced in the laboratory using AC-30 binder with different combinations of basalt–RHL, and basalt–NHL fillers. The dosages of RHL and NHL were selected as 0%, 5%, 10%, 15%, and 20% by weight of asphalt binder, and the percentage of basalt filler was adjusted accordingly. Filler to binder (F/B) ratio was selected as 0.8 (by mass ratio) for all mastic sample preparation. The fatigue damage behavior (number of cycles to fatigue damage/failure) of asphalt mastic was evaluated using a linear amplitude sweep (LAS) test. Further, the interfacial bond strengths of asphalt mastic and aggregate samples were evaluated using the bitumen bond strength (BBS) test. Overall test results indicate that mineralogy, surface area, and interaction properties of RHL and NHL fillers have a significant effect on fatigue, bond strength, and moisture damage performance of asphalt mastic. The results from the LAS test showed that NHL filler predominantly enhanced the fatigue life of asphalt mastic as compared with RHL filler. BBS test results imply that the contribution of NHL filler is significant over RHL filler in improving the bond strength and moisture damage resistance of asphalt mastic. Overall asphalt mastic with 20% NHL filler had better fatigue life, bond strength, and moisture damage performance over mastic with other percentages of RHL or NHL fillers.

In this study, a modified asphalt based trackless tack coat material (TTCM) was prepared by adding styrene–butadiene–styrene, uintaite mastic asphalt, anti-rut asphalt master batch and Sasobit wax to 50# base asphalt (penetration grade). Mehcnaimcal properties like track resistance, shear strength, pull-off strength, and rheological as well as temperature performance of TTCM were studied. Results showed that the adhesive bond strength of TTCM was greater than cohesive forces within hot mix asphalt layer, track-free time was less than 1 min and it did not deteriorate upon contact with tyres at 60 °C. Furthermore, bonding mechanism of TTCM was proposed. Surface morphology and functional group characterization were achieved using SEM and FTIR, respectively. The present approach utilizing routine raw materials and ease of operation for the synthesis of novel modified asphalt based TTCM with enhanced performance can be effectively applied on industrial level production for practical applications.

This paper presents the self-healing results of asphalt mastic by the action of calcium-alginate capsules containing sunflower oil. The morphological, physical, thermal and mechanical properties of the capsules have been evaluated. Additionally, the effect of the capsule oil content and the healing temperature on the self-healing properties of asphalt mastic have been evaluated. It was proven that the capsules can resist the mixing and compaction processes and break inside the asphalt mastic due to mechanical loads, releasing the oil. Healing levels in the asphalt mastic samples with capsules were greater than samples without capsules. The healing level depended on the oil content of the capsules and temperature.

Subject: a rapid increase in the traffic intensity and freight traffic on motor roads leads to premature destruction of road surfaces. At the same time, the actual service life of asphalt-concrete pavements rarely exceeds 4-5 years and in most cases is only 2-3 years. Most intensively defects and fractures appear on asphalt-concrete pavements in the early spring. Nowadays the overhaul intervals for the road surface coverings are significantly lower than those given by the regulatory requirements. One of the main reasons for this phenomenon is the use of obsolete technologies based on traditional materials whose properties are inadequate to resist stresses and deformations arising in the coating. This is especially evident in the climatic conditions of the south of the European part of Russia, where the upper layers of the roadway experience a much wider range of temperatures. Tighter requirements for the initial road-building materials and timely repair of the coatings allow us to increase the service life of motor roads. Research objectives: the aim of the study is to develop a new type of asphalt-concrete, such as porous-mastic one. Materials and methods: the work was carried out based on observations and published sources, a method of theoretical study and analysis. Results: the domestic and foreign experience of using the given asphalt concrete for the top layer of the coating was considered. The technology of preparation and laying of a porous-mastic asphalt-concrete mixture is presented and its advantages and disadvantages are shown. Conclusions: increasing the longevity of highways is an important and urgent task and it can be solved, in particular, due to the wide use of new technologies and non-traditional building materials that allow us to improve the quality of asphalt-concrete pavement and prolong its overhaul intervals.

The microstructures of asphalt mastic have been considered as an important micromechanical mixture property related to the macro performance of asphalt mixtures based on the multi-scale analysis me...

Mastic asphalt (MA) has been recognized as one of the most deformation-resistant and thus durable materials for bridge pavement. The performance properties of MA are highly dependent on the physical and rheological properties of the binder applied in the MA mixture. To modify the binder properties to obtain the expected performance of the MA mixture, Trinidad Lake Asphalt (TLA) is often applied. In this study, the TLA-modified binders to be used in mastic asphalt bridge pavement systems were evaluated to develop the optimum material combination using conventional and performance-related testing. Physical and rheological tests were carried out on TLA-modified binders with the different modifier content in the range of 10–50% on a weight basis. The tests revealed that the TLA modifier addition to the 35/50 base bitumen should be close to the value of 20%. Higher concentrations of TLA may make the binder very stiff and could induce low-temperature cracks in mastic asphalt.

The cracking behavior of asphalt mixtures in the shape of angled edge crack semi-circular bend (SCB) specimens created by the generation and packing algorithm was investigated numerically. Using extensive two-dimensional finite element analyses, the effects of crack length and crack inclination angle, elastic modulus of aggregates and mastic parts, Poisson’s ratios of aggregates and mastic parts, shape of aggregates, distribution pattern for the aggregates inside the asphalt mastic, crack tip location, and air void distribution on geometry factors (YI and YII) were investigated. It was shown that the crack tip location has a significant effect on the magnitude and sign of geometry factors but the shape of aggregates had no sound influence on both modes I and II stress intensity factors. Geometry factors obtained from heterogeneous modeling (i.e. two-phase aggregate/mastic asphalt mixture) when the crack tip is located inside the aggregates were greater than those obtained from homogeneous model. On the other hand, if the crack tip is located inside the mastic part, the geometry factors will be smaller than the homogeneous SCB model. The crack growth path was predicted using the maximum tensile stress criterion. It was shown that the aggregates could change the crack growth path locally; however, the general direction of crack growth in heterogeneous and homogeneous modeling is the same.

Aging of asphalt binders is induced by chemical or physicochemical changes during production of pavement and throughout its service life. Although binder aging in pavement always occurs while binders are in contact with aggregates and mineral filler, in most laboratory aging studies and in current specifications, asphalt binders are individually aged without accounting for aggregate induced interactions. Past research has had conflicting findings, as it attributes mitigating or catalytic effects to the presence of mineral fillers in asphalt binders with oxidative aging. Thus, in the present study it was hypothesized that evaluation of asphalt oxidative aging without taking into account the interactive effect of the presence of mineral fillers was inadequate as a specification tool. The effect of mineral fillers on oxidative aging of asphalt was investigated with accelerated aging of mastics (asphalt and fillers) in a pressure aging vessel (PAV) and by measuring the changes in stiffness and glass transition temperature ( Tg). The testing matrix included an aging evaluation of mastics containing different fillers, mineralogy, and surface area. The results showed that the low-temperature behavior of aged mastic could be modified by controlling filler concentration and type. The fillers acted as an agent adsorbing heavy fractions of asphalt binder and therefore reduced stiffness and changing Tg. During oxidative aging of asphalt binders and mastics, diffusion and adsorption mechanisms played a role in the rate of aging of asphaltic material. The results provided insight on the potential for selecting a mineral filler concentration and mineralogy type to reduce the impact of oxidative aging and possibly improve the service life of pavement.

Freeze-thaw damage is a typical distress incurred in road and railway engineering in cold regions. Concrete waterproofing layer is commonly used in high-speed railway tracks to prevent the penetration of surface water, however, it cracks easily under thermal stress, especially in cold regions. Recently solutions have been proposed to increase the waterproofing layer’s cracking resistance by using asphalt layers. Nonetheless, the use of emulsified asphalt as well as dense-graded asphalt mixture were not effective enough. To improve the effectiveness, in this study, mastic asphalt was designed for application as the waterproofing layer on the subgrade surface of high-speed railway tracks in cold regions. The overall performance of mastic asphalt was preliminarily evaluated by laboratory tests, then a 200-m test section was constructed for field validation in northeastern China as part of a new high-speed railway line, and water content sensors were placed inside the subgrade to monitor the performance of the mastic asphalt waterproofing layer (MAWL). The subsequent field investigation and monitoring data during the two years operation showed that MAWL dramatically outperformed the conventional concrete waterproofing layer in terms of waterproof performance. Plenty of serious cracks were found in the conventional concrete waterproofing layer, but only a limited number of local cracks were observed in MAWL. As a result, MAWL keeps the water content of subgrade at a stable level. In addition, MAWL showed relatively high stability during the two years investigation period, and no obvious deterioration was observed in the test section.

Temperature reduction of mastic asphalt (MA) mixtures can decrease costs and energy demand, as well as health-relevant emissions of particulate matter throughout the life cycle. A state-of-the-art method for temperature reduction is wax modification of the bituminous binder to reduce its viscosity. In this paper, the results of an extensive study. On mechanical performance, particulate matter emission and life-cycle analysis of temperature-reduced MA are presented. Therefore, a reference MA is compared to three temperature-reduced MAs: a state-of-the-art reduction by modification with amide wax (AW) and an alternative method of substituting crushed aggregates by rounded ones. For both methods, a temperature reduction of 30°C can be realised. In addition, a combination of both methods, wax modification and use of rounded aggregates, is investigated. For this combination a reduction of 50°C is possible. The results show that the resistance to permanent deformation is not decreased by using rounded aggregates and that it can be doubled by employing AW regardless of the aggregate shape. Resistance to low-temperature cracking is not affected by any of the studied methods for temperature reduction. Emission analysis reveals that more than 80% of the emitted particulates are below 2.5 µm a.d. (aerodynamic diameter). From a life-cycle perspective, a main benefit of temperature-reduced MAs is the significant decrease in particulate emissions by up to 80% in case of 50°C temperature reduction. Also, up to 20% of production process energy can be saved when the mixing temperature is reduced by 50°C. Application of a wax additive reduces process energy costs, but increases the total life-cycle costs. Based on the considered scenarios, the application of additives is controversial and the substitution of crushed aggregates by rounded aggregates seems to be beneficial.