New innovations in pavement materials and engineering: A review on pavement engineering research 2021

Sustainable and resilient pavement infrastructure is critical for current economic and environmental challenges. In the past 10 years, the pavement infrastructure strongly supports the rapid development of the global social economy. New theories, new methods, new technologies and new materials related to pavement engineering are emerging. Deterioration of pavement infrastructure is a typical multi-physics problem. Because of actual coupled behaviors of traffic and environmental conditions, predictions of pavement service life become more and more complicated and require a deep knowledge of pavement material analysis. In order to summarize the current and determine the future research of pavement engineering, Journal of Traffic and Transportation Engineering (English Edition) has launched a review paper on the topic of “New innovations in pavement materials and engineering: A review on pavement engineering research 2021”. Based on the joint-effort of 43 scholars from 24 well-known universities in highway engineering, this review paper systematically analyzes the research status and future development direction of 5 major fields of pavement engineering in the world. The content includes asphalt binder performance and modeling, mixture performance and modeling of pavement materials, multi-scale mechanics, green and sustainable pavement, and intelligent pavement. Overall, this review paper is able to provide references and insights for researchers and engineers in the field of pavement engineering

Eleventh International Conference on the Bearing Capacity of Roads, Railways and Airfields

Innovations in Road, Railway and Airfield Bearing Capacity – Volume 2 comprises the second part of contributions to the 11th International Conference on Bearing Capacity of Roads, Railways and Airfields (2022). In anticipation of the event, it unveils state-of-the-art information and research on the latest policies, traffic loading measurements, in-situ measurements and condition surveys, functional testing, deflection measurement evaluation, structural performance prediction for pavements and tracks, new construction and rehabilitation design systems, frost affected areas, drainage and environmental effects, reinforcement, traditional and recycled materials, full scale testing and on case histories of road, railways and airfields. This edited work is intended for a global audience of road, railway and airfield engineers, researchers and consultants, as well as building and maintenance companies looking to further upgrade their practices in the field

Prediction of permanent deformation in asphalt mixtures

An asphalt mixture is combined of different sizes of aggregate, filler, and bitumen for application on the most common road construction materials. In asphalt pavement material there are different types of distress such as permanent deformation (rutting), fatigue cracking, ravelling, potholes, stripping, etc. There are many reasons for these types of distress, some of them related to the pavement structure, e.g. whether the underlying layers are weak, others related to the mixture properties. Other causes could be related to external conditions such as high temperature, high axle load, long duration of load application, etc. This research has focused on the permanent deformation (rutting) as a function of aggregate gradation. The aggregate gradations of more than twenty asphalt mixtures, manufactured with different gradations, were analysed by using the Bailey method of gradation analysis. The analysis was performed in relation to Repeated Load Axial Test (RLAT) testing results to study the performance of each mixture. The results showed that the Bailey method is not capable on its own to define the differences between the gradations of each mixture. Therefore, three more packing ratios were introduced to adequately describe the aggregate gradation. The aggregate particle packing was extensively studied through these packing ratios and it was shown how the different particle sizes interact with each other. Images were taken for two mixtures to validate the theory behind the ratios. The five packing ratios (two of Bailey and three new ratios) were used in Artificial Neural Network (ANN) and Adaptive Neuro-Fuzzy Inference System (ANFIS) techniques for all the mixtures as input data to predict the mixture performance (RLAT permanent deformation and Indirect Tensile Stiffness Modulus ITSM stiffness modulus) and they showed good prediction capability. After establishing the impact of aggregate packing on the performance, six mixtures were re-manufactured and re-tested with different variables; the selection of the mixtures was made to cover a range of different gradations (ratios). The aim of this step was to understand the effect of these variables on the asphalt mixture in the light of the packing ratios. The variables that were used were binder content, testing temperature and compaction effort. The binder content results showed an interesting effect on the permanent deformation and stiffness of the asphalt mixture. The packing of aggregate was very helpful in understanding the different mixture behaviour with different binder content. The effect of aggregate packing was not shown at relatively low testing temperature, but as the temperature rises the aggregate packing effect starts to appear. The effect of compaction which was represented by the number of gyrations in gyratory compactor was inconsistent; results show over-compaction can lead to poor performance. Finally, a linear viscous method was introduced aiming to predict the rutting in an asphalt mixture. The method was based on using a multilayer linear programme (BISAR) and using viscous parameters of the mixture as input. The non-linear properties of the material were incorporated by using the RLAT test. For this purpose, six mixtures were used and tested in a wheel tracking machine. The predicted results were compared with the wheel tracking rut depth in the laboratory and showed good agreement at different temperatures. However, at high temperature (50 °C) the material properties in the RLAT test did not behave as linear viscous, which resulted in a much poorer prediction. Trials were made to predict field rut but it was found that special requirements were needed for the approach which were not available at the time of the research. However, for the available field data, the method was found to be a good predictor

Multiscale Rheological and Mechanical characterization of Cold Mixtures

openOggigiorno, la crescente consapevolezza sociale e politica per le questioni ambientali si sta orientando verso lo sviluppo di tecnologie a basso consumo ed emissioni. In questo contesto, tecnologie come le miscele bituminose a freddo possono rappresentare una valida alternativa ai tradizionali conglomerati bituminosi a caldo, per le pavimentazioni stradali. Inoltre, quando vengono utilizzati materiali provenienti dal riciclaggio di pavimentazioni stradali ammalorate, il consumo di aggregati vergini può essere considerevolmente ridotto. In passato, l'uso di miscele bituminose a freddo ha riscosso limitato successo a causa dei problemi legati al tempo necessario per il completo sviluppo di resistenza e la suscettibilità all’acqua nei primi mesi di vita. Il presente dottorato di ricerca è volto a valutare scientificamente i vantaggi/svantaggi dell’adozione di miscele bituminose a freddo. Oltre alle tradizionali indagini di laboratorio, è stata adottata una metodologia originale basata sulla caratterizzazione multiscala del materiale, sia dal punto di vista fisico che reologico. Infatti, la miscela bituminosa a freddo può considerarsi un materiale evolutivo poiché il suo stato fisico evolve nel tempo a causa della continua perdita di umidità. In questo contesto, la caratterizzazione delle miscele bituminose a freddo deve essere sviluppata su scale temporali differenti durante la vita in servizio del materiale, e a diversi livelli di indagine (scala dimensionale). I risultati raccolti hanno mostrato una correlazione ottimale tra i diversi livelli di indagine; a dimostrazione del fatto che il metodo di ricerca adottato può ritenersi scientificamente valido e inoltre, nessun elemento scoraggia l'uso delle miscele bituminose a freddo come strati di supporto per la sovrastruttura stradale. Ad ogni modo, i materiali impiegati devono essere adeguatamente progettati in termini di assortimento granulometrico, contenuto d’acqua e leganti (tipologia e dosaggio).Nowadays, the growing social and political awareness about environmental issues is moving towards the development of low-energy and low-emission technologies. In this context, technologies as cold mixtures may represent a valid alternative to traditional hot mix asphalt for road pavements. Moreover, when materials obtained from the recycling of old pavements are adopted, the consumption of virgin aggregate can be significantly reduced. In the past, the use of cold mixture for structural layers has attracted relatively little attention largely because of problems related to the time required for full strength to be achieved after paving and its susceptibility to early life damage by rainfall. The PhD research aimed at scientifically evaluating advantages and disadvantages of cold mixtures. Besides the traditional laboratory investigations, an original research methodology based on the multiscale characterization of the material, from both physical and rheological point of view. In fact, cold mixture can be considered as an evolutive material because its physical state evolves over time according to moisture loss. In this context, the characterization of cold mixture should be developed at different time during its in-service life (time-scale) and at different level of investigation (size-scale). Optimum correlation was found between results collected from different levels of investigation (size and time-scales); hence demonstrating the scientific validity of the adopted research approach. Based on the overall findings, no elements discourage the use of cold mixtures as support layers for pavement structure. Therefore, materials should be properly designed in terms of aggregate blend, water content and binding agents (type and dosage).INGEGNERIA CIVILE, AMBIENTALE, EDILE E ARCHITETTURAopenGodenzoni, CarlottaGodenzoni, Carlott

Multiscale Rheological and Mechanical characterization of Cold Mixtures

Oggigiorno, la crescente consapevolezza sociale e politica per le questioni ambientali si sta orientando verso lo sviluppo di tecnologie a basso consumo ed emissioni. In questo contesto, tecnologie come le miscele bituminose a freddo possono rappresentare una valida alternativa ai tradizionali conglomerati bituminosi a caldo, per le pavimentazioni stradali. Inoltre, quando vengono utilizzati materiali provenienti dal riciclaggio di pavimentazioni stradali ammalorate, il consumo di aggregati vergini può essere considerevolmente ridotto. In passato, l'uso di miscele bituminose a freddo ha riscosso limitato successo a causa dei problemi legati al tempo necessario per il completo sviluppo di resistenza e la suscettibilità all’acqua nei primi mesi di vita. Il presente dottorato di ricerca è volto a valutare scientificamente i vantaggi/svantaggi dell’adozione di miscele bituminose a freddo. Oltre alle tradizionali indagini di laboratorio, è stata adottata una metodologia originale basata sulla caratterizzazione multiscala del materiale, sia dal punto di vista fisico che reologico. Infatti, la miscela bituminosa a freddo può considerarsi un materiale evolutivo poiché il suo stato fisico evolve nel tempo a causa della continua perdita di umidità. In questo contesto, la caratterizzazione delle miscele bituminose a freddo deve essere sviluppata su scale temporali differenti durante la vita in servizio del materiale, e a diversi livelli di indagine (scala dimensionale). I risultati raccolti hanno mostrato una correlazione ottimale tra i diversi livelli di indagine; a dimostrazione del fatto che il metodo di ricerca adottato può ritenersi scientificamente valido e inoltre, nessun elemento scoraggia l'uso delle miscele bituminose a freddo come strati di supporto per la sovrastruttura stradale. Ad ogni modo, i materiali impiegati devono essere adeguatamente progettati in termini di assortimento granulometrico, contenuto d’acqua e leganti (tipologia e dosaggio).Nowadays, the growing social and political awareness about environmental issues is moving towards the development of low-energy and low-emission technologies. In this context, technologies as cold mixtures may represent a valid alternative to traditional hot mix asphalt for road pavements. Moreover, when materials obtained from the recycling of old pavements are adopted, the consumption of virgin aggregate can be significantly reduced. In the past, the use of cold mixture for structural layers has attracted relatively little attention largely because of problems related to the time required for full strength to be achieved after paving and its susceptibility to early life damage by rainfall. The PhD research aimed at scientifically evaluating advantages and disadvantages of cold mixtures. Besides the traditional laboratory investigations, an original research methodology based on the multiscale characterization of the material, from both physical and rheological point of view. In fact, cold mixture can be considered as an evolutive material because its physical state evolves over time according to moisture loss. In this context, the characterization of cold mixture should be developed at different time during its in-service life (time-scale) and at different level of investigation (size-scale). Optimum correlation was found between results collected from different levels of investigation (size and time-scales); hence demonstrating the scientific validity of the adopted research approach. Based on the overall findings, no elements discourage the use of cold mixtures as support layers for pavement structure. Therefore, materials should be properly designed in terms of aggregate blend, water content and binding agents (type and dosage)

Foamed bitumen stabilised sandstone aggregates

Roads form a key element for the expansion of economy and development of a country. As with most countries, Brunei Darussalam has been facing a rapid development to meet the economic growth that requires an efficient road network. Therefore, the scarcity of conventional road aggregates in Brunei Darussalam means that the country has a strong dependence on imported aggregates from overseas to construct quality roads. Further restrictions on local road specifications make it almost impossible to include low quality granular materials. The study reported in this thesis was undertaken on the basis that the dependence on overseas resources is not a viable long- term solution. The research task has been, therefore, to ascertain the quality of local sandstones for road construction and then to propose means to upgrade their performance quality for optimum utilisation in cost effective applications. This study focused on the road base layer since that is where most aggregate is used. The approach used for this study was to identify the common rock in Brunei Darussalam and review the candidate treatment methods. A weighted matrix for these candidate treatment methods was constructed to determine the overall ranking with selected key criteria on the basis of the local climatic condition, construction preferences and traditions. From the reviews, Foamed bitumen was selected as a feasible treatment method that can improve the sandstone characteristics under local conditions. Three curing conditions were adopted in this study, simulating extreme field conditions in Brunei Darussalam, to characterise the mechanical properties of foamed bitumen stabilised sandstone mixtures, termed 'foam mix'. The following tests were conducted

Engineering and built environment project conference 2015: book of abstracts - Toowoomba, Australia, 21-25 September 2015

Book of Abstracts of the USQ Engineering and Built Environment Conference 2015, held Toowoomba, Australia, 21-25 September 2015. These proceedings include extended abstracts of the verbal presentations that are delivered at the project conference. The work reported at the conference is the research undertaken by students in meeting the requirements of courses ENG4111/ENG4112 Research Project for undergraduate or ENG8411/ENG8412 Research Project and Dissertation for postgraduate students

Prediction of permanent deformation in asphalt mixtures

An asphalt mixture is combined of different sizes of aggregate, filler, and bitumen for application on the most common road construction materials. In asphalt pavement material there are different types of distress such as permanent deformation (rutting), fatigue cracking, ravelling, potholes, stripping, etc. There are many reasons for these types of distress, some of them related to the pavement structure, e.g. whether the underlying layers are weak, others related to the mixture properties. Other causes could be related to external conditions such as high temperature, high axle load, long duration of load application, etc. This research has focused on the permanent deformation (rutting) as a function of aggregate gradation. The aggregate gradations of more than twenty asphalt mixtures, manufactured with different gradations, were analysed by using the Bailey method of gradation analysis. The analysis was performed in relation to Repeated Load Axial Test (RLAT) testing results to study the performance of each mixture. The results showed that the Bailey method is not capable on its own to define the differences between the gradations of each mixture. Therefore, three more packing ratios were introduced to adequately describe the aggregate gradation. The aggregate particle packing was extensively studied through these packing ratios and it was shown how the different particle sizes interact with each other. Images were taken for two mixtures to validate the theory behind the ratios. The five packing ratios (two of Bailey and three new ratios) were used in Artificial Neural Network (ANN) and Adaptive Neuro-Fuzzy Inference System (ANFIS) techniques for all the mixtures as input data to predict the mixture performance (RLAT permanent deformation and Indirect Tensile Stiffness Modulus ITSM stiffness modulus) and they showed good prediction capability. After establishing the impact of aggregate packing on the performance, six mixtures were re-manufactured and re-tested with different variables; the selection of the mixtures was made to cover a range of different gradations (ratios). The aim of this step was to understand the effect of these variables on the asphalt mixture in the light of the packing ratios. The variables that were used were binder content, testing temperature and compaction effort. The binder content results showed an interesting effect on the permanent deformation and stiffness of the asphalt mixture. The packing of aggregate was very helpful in understanding the different mixture behaviour with different binder content. The effect of aggregate packing was not shown at relatively low testing temperature, but as the temperature rises the aggregate packing effect starts to appear. The effect of compaction which was represented by the number of gyrations in gyratory compactor was inconsistent; results show over-compaction can lead to poor performance. Finally, a linear viscous method was introduced aiming to predict the rutting in an asphalt mixture. The method was based on using a multilayer linear programme (BISAR) and using viscous parameters of the mixture as input. The non-linear properties of the material were incorporated by using the RLAT test. For this purpose, six mixtures were used and tested in a wheel tracking machine. The predicted results were compared with the wheel tracking rut depth in the laboratory and showed good agreement at different temperatures. However, at high temperature (50 °C) the material properties in the RLAT test did not behave as linear viscous, which resulted in a much poorer prediction. Trials were made to predict field rut but it was found that special requirements were needed for the approach which were not available at the time of the research. However, for the available field data, the method was found to be a good predictor