The effect of crumb rubber on asphalt pavement resistance to rutting and thermal cracking

Siekiant užtikrinti tvarų ir ilgalaikį asfalto dangos funkcionavimą, būtina naudoti aukščiausios kokybės mineralines medžiagas ir modifikuotą bitumą. Įprastai Lietuvoje bitumas modifikuojamas naudojant polimerus, kurie yra brangūs. Panaudotų padangų gumos sudėtyje yra daugiau kaip 50 % polimerų, todėl nekyla abejonių, kad panaudotų padangų guma gali būti tinkama kelių bitumo modifikavimui. Tačiau būtina nustatyti tinkamas kelių bitumo modifikavimo sąlygas, kurios užtikrintų tvarų ir ilgalaikį įrengtų asfalto dangų funkcionavimą. Disertacijos tikslas – nustatyti ir moksliškai pagrįsti kelių bitumo modifikavimui pakankamus panaudotų padangų gumos kiekius užtikrinant kelio dangos atsparumą provėžų bei plyšių susidarymui. Disertaciją sudaro įvadas, trys skyriai, bendrosios išvados, rekomendacijos, literatūros šaltinių ir autoriaus publikacijų disertacijos tema sąrašas, santrauka anglų kalba ir aštuoni priedai. Įvade formuluojama problema, aprašomas darbo aktualumas, tyrimų objektas, pateikiamas darbo tikslas ir uždaviniai, tyrimų metodika, darbo mokslinis naujumas ir jo reikšmė, pateikiama darbo rezultatų praktinė reikšmė, ginamieji teiginiai bei darbo struktūra. Pirmame skyriuje apžvelgta mokslinė literatūra. Atlikta asfalto mišinio komponentų įtakos kelio dangos funkcionavimui analizė, panaudotų padangų gumos paruošimo technologijų analizė, bitumo modifikavimui modifikavimo technologijų analizė, išnagrinėti moksliniai tyrimai kelių bitumo ir asfalto mišinių modifikavimo panaudotų padangų guma tematika. Siekiant nustatyti ir moksliškai pagrįsti kelių bitumo modifikavimui pakankamus panaudotų padangų gumos kiekius užtikrinant atsparumą provėžoms bei plyšiams, atliktas eksperimentinis tyrimas, aprašytas antrame skyriuje. Skyriuje analizuojama gumos kiekio įtaka bitumo savybėms aukštoje bei žemoje temperatūroje. Įvertinta modifikuoto bitumo valkšnioji atstata. Aprašytas eksperimentinio tyrimo objektas, tyrimo metodika, naudotos medžiagų savybės. Pateikta modifikuoto bitumo fizinių ir mechaninių savybių nustatymo rezultatų analizė. Trečiame skyriuje atliktas modifikuoto bitumo eksploatacinių savybių vertinimas pagal Superpave (PG) sistemą, nustatytas asfalto mišinio su guma modifikuotu bitumu atsparumas provėžoms, atliktas bitumo ir asfalto mišinių atsparumo provėžoms rodiklių priklausomybės vertinimas, bitumo modifikavimo guma ekonominio efekto skaičiavimas, racionaliausio bitumo modifikavimo panaudojant gumą varianto parinkimas taikant daugiakriterį SAW metodą. Disertacijos tema yra atspausdinti 14 mokslinių straipsnių: trys – mokslo žurnaluose, įtrauktuose į Clarivate Analytics Web of Science duomenų bazę, du – recenzuojamame mokslo žurnale, penki – tarptautinių konferencijų leidiniuose, referuojamuose Clarivate Analytics duomenų bazėje Proceedings, keturi – kitose tarptautinių ir respublikinių konferencijų leidiniuose

Evaluation of Asphalt Mix with Dolomite Aggregates for Wearing Layer

AbstractBearing capacity and durability of road pavement structure depends on design solution, transport loads, climate, materials and construction quality. But the main factors are selected materials for road pavement structure and their properties. Typically, there are selected high quality aggregates for asphalt wearing layer of heavy duty pavement. In Lithuania, granite aggregates are often used for asphalt wearing layer, but this magmatic rock is imported from other countries. Dolomite is one of the most available sedimentary rocks in Lithuania and quarries contain hundreds million tons of this material. Either, high quality dolomite is produced applying special extraction technology, and the mechanical properties of this material are similar to granite. The aim of this research is to evaluate high quality dolomite as aggregates for asphalt wearing layer and to design rut resistant asphalt mix with dolomite aggregates. Test results showed good bitumen-aggregate adhesion properties. There were designed asphalt concrete (AC) mixes using granite and high quality dolomite aggregates and stone mastic asphalt (SMA) mixes using high quality dolomite aggregates based on fundamental properties in accordance to standard EN 13108-1 and EN 13108-5. Resistance to permanent deformation of asphalt mixes is achieved by designing coarser gradation mixes with higher content of air voids (3–4%) comparing to traditional asphalt mixes for wearing layer (2–4%). Designed asphalt mixes were tested using empirical and performance based tests, which showed promising results for asphalt mixes with high quality dolomite aggregates

Definition of concrete and composite precast concrete pavements texture

In the context of increasing traffic demands and emerging mobility trends road infrastructure has to shift towards the fifth generation of roads, which according to Forever Open Road (FOR) vision are envisioned as adaptable to traffic volumes, resilient to changing weather conditions, quickly built, effectively maintained, suitable for retrofitting, self-monitoring, self-repairing and recyclable. Concrete modular pavements can be defined as an example of such type of road infrastructure. Functional needs are mainly associated with implementation area/location, traffic and mobility demands, environmental constraints and etc. This also has a significant impact on the selection of Precast Concrete Pavements (PCP) texture formation method and materials. Concrete pavement surface texture affects both safety and tyre/road noise characteristics. Exposed Aggregate Concrete (EAC) and porous concrete are the most suitable noise reducing solutions for highways and streets wearing layer even in severe traffic and climate conditions. According to the literature analysis, the algorithm of highways and streets low noise concrete design was created. It is recommended to use the highest quality aggregates with maximum size up to 8 mm, gap-graded gradation, higher amount of cement and lower water/cement ratio. The most important characteristics of EAC are Mean Profile Depth (MPD), Mean Texture Depth (MTD) and profile count, while the most important characteristics of porous concrete are compressive strength, outflow and air void content

Selection of Constituent Materials for Asphalt Mixtures of Noise-Reducing Asphalt Pavements

Road traffic noise is a widespread problem, especially in the densely populated cities of Europe. Exposure to high levels of (traffic) noise leads to health problems, such as stress, sleep disturbance and even heart diseases. Noise-reducing asphalt pavements are more frequently developed and selected as a first noise abatement solution. Performance of noise-reducing asphalt pavement depends on the composition and properties of asphalt mixture components, and pavement properties such as layer thickness, voids in pavement, texture. Design of asphalt mixture for the noise-reducing asphalt pavements is even more complicated for severe and cold climate regions where significant temperature fluctuations and many of frost-thaw cycles occur. Thus, the balance between mechanical and acoustical durability depends on the proper selection of asphalt mixture components. Components of these asphalt mixtures have primarily to be tested to determine their physical and mechanical properties. The main aim of this research is to evaluate properties of local aggregates, bituminous binders, and regarding test results, select the most suitable materials for the design of high-quality, durable asphalt mixture for noise-reducing asphalt pavements. The research showed that Granite A is the most suitable aggregate for the design of asphalt mixtures for noise-reducing asphalt pavement. Short-term and particularly long-term ageing of polymer modified bituminous binder PMB 45/80-65 and PMB 25/55-60 decreases the number of aromatics and increases the amount of resins. Based on Multiple Stress Creep and Recovery test results, it is assumed that all bituminous binders selected for research are suitable for the asphalt mixture design of noise-reducing asphalt pavement in terms of resistance to rutting. However, considering all tests results, bituminous binder PMB 45/80-65 (1) showed the best performance and was the most suitable for the asphalt mixture design of noise-reducing asphalt pavement

Asphalt Pavement Acoustic Performance Model

Low-noise pavements are used as an effective method of traffic noise mitigation. Low-noise pavements reduce the noise that arises due to interactions between tires and road surfaces (tire/road) via the implementation of three main components: low pavement roughness, negative pavement texture, and a high pavement air-void content. The tire/road noise reduction capabilities of the wearing layer vary depending on the aggregate type, gradation, bitumen and air-void content, and density. Consequently, the demand for an accurate tire/road noise prediction model has arisen from the design of asphalt mixtures. This paper deals with how asphalt mixture components of the wearing layer influence tire/pavement noise reduction and presents a model for tire/road noise level prediction based on the asphalt mixture composition. The paper demonstrates that the noise reduction level of low-noise asphalt pavements is dependent on the composition of the asphalt mixture. Asphalt wearing layer mixture composition parameters were tested in the laboratory from cores taken from 18 road sections, where acoustic properties were measured using a close-proximity (CPX) method. The proposed linear model is based on the bitumen amount, the air-void content of the mixture and aggregate shape and involves materials that comply with the general requirements for high-quality asphalt mixtures. The model allows for the prediction of the tire/road noise level at the asphalt mixture design stage using asphalt mixture components and volumetric properties. The proposed model is the first stage in the building of a complex model with a much wider range of low-noise asphalts components, pavement profile depth and CPX-value relationships.This article belongs to the Special Issue Sustainability in Civil Engineering: from Sustainable Materials to Sustainable StructuresThis project has received funding from the Research Council of Lithuania (LMTLT), agreement No S-MIP-17-137

Asphalt Pavement Acoustic Performance Model

Low-noise pavements are used as an effective method of traffic noise mitigation. Low-noise pavements reduce the noise that arises due to interactions between tires and road surfaces (tire/road) via the implementation of three main components: low pavement roughness, negative pavement texture, and a high pavement air-void content. The tire/road noise reduction capabilities of the wearing layer vary depending on the aggregate type, gradation, bitumen and air-void content, and density. Consequently, the demand for an accurate tire/road noise prediction model has arisen from the design of asphalt mixtures. This paper deals with how asphalt mixture components of the wearing layer influence tire/pavement noise reduction and presents a model for tire/road noise level prediction based on the asphalt mixture composition. The paper demonstrates that the noise reduction level of low-noise asphalt pavements is dependent on the composition of the asphalt mixture. Asphalt wearing layer mixture composition parameters were tested in the laboratory from cores taken from 18 road sections, where acoustic properties were measured using a close-proximity (CPX) method. The proposed linear model is based on the bitumen amount, the air-void content of the mixture and aggregate shape and involves materials that comply with the general requirements for high-quality asphalt mixtures. The model allows for the prediction of the tire/road noise level at the asphalt mixture design stage using asphalt mixture components and volumetric properties. The proposed model is the first stage in the building of a complex model with a much wider range of low-noise asphalts components, pavement profile depth and CPX-value relationships

Concrete Modular Pavements – Types, Issues And Challenges

According to the European Asphalt Pavement Association, more than 90 per cent of the European road network is paved with asphalt. Constantly increasing traffic volume and climate change accelerate deterioration of current pavements. As a result, there arises a need to rehabilitate them prematurely. Repair and rehabilitation work lead to traffic congestion, which is one of the most significant concerns in highly trafficked roads and urban streets. Concrete modular pavements consisting of precast concrete slabs are a reasonable solution to deal with the road works since their construction, as well as repair, is time-saving. Repair works typically are implemented during a low traffic period (usually at night). A primary purpose of concrete modular pavements is heavily trafficked roads and other transport areas. This paper focuses on concrete modular pavements, their types, issues and challenges related to their design, slab fabrication and pavement construction. The conducted analysis revealed 15 different types of concrete modular pavements that differ from the techniques of slab joints and load transfer between the adjacent slabs. More than 20 issues and challenges related to the design of modular elements, slab fabrication and pavement construction were identified. Finally, the existing practice of concrete modular pavements was summarised and the gaps of scientific knowledge, as well as a need for comprehensive research, were defined

Potential of MSWI bottom ash to be used as aggregate in road building materials

In the European Union, more than 140 million tonnes of municipal solid waste is incinerated annually. It generates about 30–40 million tonnes of residues known as municipal solid waste incinerator bottom ash, which is typically landfilled. To deal with growing landfills, there is a need to utilize municipal solid waste incinerator bottom ash as a building material. It has been known that municipal solid waste incinerator bottom ash properties strongly depend on waste composition, which is directly influenced by people’s habits, economic policy, and technologies for metals recovery of bottom ash. Thus, municipal solid waste incinerator bottom ash produced in a specific country or region has primarily to be tested to determine its physical and mechanical properties. The main aim of this study is to determine municipal solid waste incinerator bottom ash physical and mechanical properties (aggregate particle size distribution, water content, oven-dried particle density, loose bulk density, Proctor density, optimal water content, California Bearing Ratio after and before soaking, permeability, Flakiness Index, Shape Index, percentage of crushed and broken surfaces, resistance to fragmentation (Los Angeles coefficient), water absorption and resistance to freezing and thawing). Municipal solid waste in-cinerator bottom ash produced in the waste-to-energy plant in Klaipėda (Lithuania) was used in this research. Ferrous and non-ferrous metals were separated after more than three months of municipal solid waste incinerator bottom ash ageing in the atmosphere. The study showed promising results from considering municipal solid waste incinerator bottom ash as possible aggregates for road building materials

Modified asphalt mixtures for heavy duty pavement wearing layers

Asphalt pavements perform in a wide range of temperatures, especially in Eastern European countries, where the daily mean temperature of asphalt layers varies from −18 °C during winter to 47 °C during summer or even higher under more severe climatic conditions. Low temperatures preclude the use of high-stiffness binders because of their high susceptibility to thermal cracking. High temperatures during summer and a heavy static load contribution cause rutting, slippage, and high plastic deformation of heavy duty asphalt pavements. Many research programs on asphalt wearing layers affected by long-lasting high stress have been initiated to address this problem. Our theoretical analysis led to a plan and subsequent detailed laboratory research of modified AC 11 VS and SMA 11 S asphalt mixtures. We analyzed 11 different bitumens and the modification of the asphalt mixture aggregate distribution. The experimental results show extremely good rutting performance of the modified asphalt mixtures.This work was supported by the European Social Fund [Grant number VP1-3.1-ŠMM-10-V-02-022]