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Pavement friction has been identified as crucial in traffic safety. Since the Highway Safety Manual prediction algorithm is often based on crash frequency, the crash severity distribution might be assumed unchanged before and after the countermeasure. However, pavement surface treatments can improve the friction to different levels, by which crash severity outcomes may vary greatly. To explore the implicit effects of pavement friction on vehicle crash severity, this paper first validates the extreme gradient boosting model performance and then the Shapley additive explanations interaction values are employed to interpret individual features and the nonlinear interactions among predictors. Under various scenarios, the extreme gradient boosting (XGBoost) output probability is utilized to convert into dynamic crash severity distributions. Results also indicate that friction becomes more significant when the friction number is less than 38, and immediate corrective actions are needed when the friction number is below 20. Key words: pavement friction, crash severity, highway safety, extreme gradient boosting (XGBoost), Shapley additive explanations (SHAP). Le frottement des chaussees a ete juge crucial pour la securite routiere. Etant donne que l'algorithme de prediction du Manuel de Securite routiere est souvent fonde sur la frequence des collisions, la distribution de la gravite des collisions peut etre consideree comme inchangee avant et apres la contre-mesure. Par contre, les traitements de surface de chaussee peuvent ameliorer le frottement a differents niveaux, par lesquels les resultats de gravite des collisions peuvent varier considerablement. Explorer les effets implicites du frottement de la chaussee sur la gravite des collisions, cet article valide d'abord les performances du modele d'amplification de gradient extreme (<< XGBoost >>), puis les valeurs d'interaction des explications additives de Shapley (SHAP) sont utilisees pour interpreter les caracteristiques individuelles et les interactions non lineaires entre les predicteurs. Dans divers scenarios, la probabilite de sortie XGBoost est utilisee pour convertir en distributions dynamiques de gravite des collisions. Les resultats indiquent egalement que le frottement devient plus important lorsque le numero de frottement est inferieur a 38 et que des mesures correctives immediates sont necessaires lorsque le numero de frottement est inferieur a 20. Mots-cles : frottement des chaussees, gravite des collisions, securite routiere, amplification de gradient extreme (<< XGBoost >>), explications additives de Shapley (<< SHAP >>)., Introduction Pavement friction plays an important role in highway safety. Poor pavement friction tends to increase the possibility of vehicle skidding or hydroplaning, leading to increased safe stop distance and [...]

Pavement crack detection has always been an important problem in pavement maintenance. With rapid development in computer vision technology, crack detection using deep learning has become one of the major tasks in automatic pavement condition detection and assessment. This paper aims to develop a method of crack grid detection based on convolutional neural network. First, an image denoising operation is conducted to improve image quality. Next, the processed images are divided into grids of different scales (10 x 10, 20 x 20, 30 x 30), and each grid is fed into a convolutional neural network for detection. The pieces of the grids with cracks are marked and then returned to the original images. Finally, on the basis of the detection results, threshold segmentation is performed only on the marked grids. Information about the crack parameters is obtained via pixel scanning and calculation, which realizes complete crack detection. The experimental results show that 30 x 30 grids perform the best with the accuracy value of 97.33%. The advantage of automatic crack grid detection is that it can avoid fracture phenomenon in crack identification and ensure the integrity of cracks. Thresholding smaller grids allows better combinations of the differences between objects and backgrounds, which makes segmentation results more accurate. Key words: convolutional neural network, pavement crack detection, maximum entropy threshold segmentation, crack type judgment, parameter calculation. La detection de fissures dans la chaussee a toujours ete un probleme important dans l'entretien de la chaussee. Avec le developpement rapide de la technologie de vision par ordinateur, la detection des fissures par l'application de l'apprentissage en profondeur est devenue l'une des taches principales de la detection et de l'evaluation automatiques de l'etat des chaussees. Cet article vise a developper une methode de detection de fissures par grille, et ce, basee sur un reseau neuronal convolutif. Tout d'abord, une operation de debruitage d'images est effectuee pour ameliorer la qualite d'image. Ensuite, les images traitees sont divisees en grilles differentes (10 x 10, 20 x 20, 30 x 30), et chaque grille est alimentee dans un reseau neuronal convolutif pour la detection. Les morceaux des grilles avec des fissures sont marques puis retournes aux images originales. Enfin, sur la base des resultats de detection, la segmentation des seuils n'est effectuee que sur les grilles marquees. L'information sur les parametres des fissures est obtenue par le balayage et le calcul des pixels, qui realisent la detection complete de fissures. Les resultats experimentaux montrent que les grilles 30 x 30 sont les plus performantes avec une precision de 97,33%. L'avantage de la detection automatique des fissures par grille est qu'elle peut eviter le phenomene de rupture lors de l'identification des fissures et assurer l'integrite des fissures. Des grilles plus petites permettent une meilleure combinaison des differences entre les objets et les arriere-plans, ce qui rend les resultats de segmentation plus precis. [Traduit par la Redaction] Mots-cles: reseau neuronal convolutif, detection de fissures dans la chaussee, segmentation maximale du seuil d'entropie, jugement du type de fissure, calcul de parametres., Introduction Pavement maintenance has always been a very important problem, which is inseparable from the detection of pavement distress. After protracted use, any pavement, whether made of asphalt or cement, [...]

In North America, highway agencies have started using Superpave as it incorporates a performance-based asphalt binder specification and a mix design analysis system. However, in a pavement management system (PMS), the performance of the pavement structure significantly influences management decisions. In this regard, accurate prediction and evaluation of performance is a very important aspect. With this in mind, this study investigates the performance of Superpave through the mechanistic-empirical (M-E) approach, field-evaluated performance, and laboratory performance tests. It considers 15 sections of highways from Ontario. The investigation found that the international roughness index (IRI) and permanent deformation are overpredicted in the M-E approach compared with field observations. Additionally, to better understand the performance, the dynamic modulus of asphalt mixtures and binder rheological testing are also performed. The master curve developed for the surface mixtures suggests a lower level of fatigue resistance that justifies the bottom-up fatigue failure in the field-observed scenarios. Key words: Superpave, mechanistic-empirical (M-E) approach, mechanistic-empirical pavement design guide (MEPDG), pavement condition evaluation, pavement performance, dynamic modulus test. En Amerique du Nord, les organismes responsables de voirie ont commence a utiliser Superpave, car ce systeme integre une specification de liant d'asphalte basee sur le rendement et un systeme d'analyse de la conception du melange. Toutefois, dans un systeme de gestion routiere (SGR), le rendement de la structure des chaussees a une incidence considerable sur les decisions de gestion. A cet egard, l'exactitude des previsions et de l'evaluation du rendement sont des aspects tres importants. Dans cette optique, la presente etude se penche sur le rendement de Superpave au moyen de l'approche mecanisteempirique (M-E), evalue le rendement sur le terrain et effectue des essais de rendement en laboratoire. On considere 15 troncons d'autoroute du reseau routier de l'Ontario. Il ressort de cet examen que l'indice de rugosite international (IRI) et la deformation permanente sont surestimes dans l'approche M-E par rapport aux observations sur le terrain. De plus, afin de mieux comprendre le rendement, un module dynamique des melanges d'asphalte et des essais rheologiques de liant sont egalement effectues. La courbe maitresse developpee pour les melanges de revetement suggere un niveau inferieur de resistance a la fatigue qui justifie la rupture par fatigue ascendante dans les scenarios observes sur le terrain. [Traduit par la Redaction] Mots-cles : Superpave, approche mecaniste-empirique (M-E), guide de conception mecanisto-empirique des chaussees (<< mechanistic-empirical pavement design guide (MEPDG) >>), evaluation de l'etat de la chaussee, tenue de la chaussee, essai du module dynamique., 1. Introduction In North America, highway agencies began using the Superior Performing Asphalt Pavements (Superpave) system in the 1990s with consideration of improved performance. Superpave is a comprehensive asphalt mix [...]

The Ministry of Transportation of Ontario was interested in a rehabilitation strategy that could be used to address deep-seated rutting issues encountered on its 400-series highways. A precast concrete inlay panel (PCIP) rehabilitation design was developed and constructed involving the installation of precast panels into partially-milled asphalt pavement. Sub- surface instrumentation was installed at the PCIP-asphalt interface including earth pressure cells and moisture sensors installed in six instrumentation clusters. This instrumentation has been monitored to gather information regarding the PCIP trial installation. Readings from the moisture sensors indicate that water penetrates beneath the PCIPs in precipitation events, though these moisture levels recede under dry conditions, indicating that the water can exit the sub-slab area. Static load testing using a fully-loaded gravel truck was used to determine the different support reactions caused by different loading configurations. Higher loads were generally found beneath the joints in the two loading situations studied. Le ministere des Transports de l'Ontario s'est penche sur une strategie de refection qui pourrait etre utilisee pour regler les problemes d'ornierage profondement enracines sur ses routes de la serie 400. La conception pour la refection au moyen de panneaux d'incrustation en beton prefabrique (PIBP) a ete developpee et realisee par l'installation de panneaux prefabriques dans un revetement d'asphalte partiellement broye. Une instrumentation enfouie a ete installee a l'interface PIBP- asphalte y compris des cellules manometriques et des sondes d'humidite installees en six regroupements d'instrumentation. Cette instrumentation a fait l'objet d'un controle afin de rassembler des informations quant a l'installation des PIBP d'essai. Les lectures des sondes d'humidite indiquent que l'eau penetre au-dessous des PIBP lors d'evenements de precipitation, quoique ces niveaux d'humidite s'estompent dans des conditions seches, indiquant que l'eau s'evacue de la zone sous les dalles. On a eu recours a un essai de charge statique avec un camion de gravier charge a capacite afin de determiner, au niveau de la portance, les diverses reactions causees par differentes configurations de chargement. Les charges plus elevees se trouvaient generalement au- dessous des joints dans les deux situations de chargement etudiees. [Traduit par la Redaction] Mots-cles : beton prefabrique, refection des chaussees, panneau de beton prefabrique incruste, reparation de routes a forte circulation., Introduction Precast concrete panels (PCPs) have been used as a paving material since as early as 1931 in the Soviet Union (Rollings and Chou 1981); however, their use has only [...]

This paper focuses on a laboratory investigation of compaction characteristics of warm mix asphalt produced with the addition of synthetic zeolites. The influence of the time elapsed between mixing and compaction operations on mix compactibility was evaluated to define an optimum 'micro-foaming time' (MFT), in which the additive can completely release the water contained. A comparison between traditional hot mix asphalt and warm mixes was carried out; two compaction methods (impact and gyratory) were used. Mix compactibility was firstly evaluated in terms of air voids content for each condition of compaction (immediately after mixing or after 1-2 h of storage in an oven). Mix resistance to densification and to distortion was investigated by means of compaction indexes and traffic indexes. Data showed that the foaming process due to the addition of the zeolite has a peak value of intensity after 1 h of MFT. This effect seems to vanish after a longer period of time. Outcomes of this study are expected to benefit both practitioners and researchers. Key words: warm mix asphalts, synthetic zeolite, asphalt workability, foaming process, compaction energy. Cet article presente une etude en laboratoire sur les caracteristiques des melanges d'asphalte tiedes produits avec l'ajout de zeolites synthetiques. L'influence du temps ecoule entre les operations de mixage et de compaction sur la compactibilite des melanges a ete evaluee afin de definir un'temps de formation de micro-mousse '(MFT) optimal durant lequel l'additif peut completement liberer l'eau qu'il contient. L'asphalte melange a chaud traditionnel et les melanges tiedes ont ete compares et deux methodes de compaction (impact/giratoire) ont ete utilisees. La compactibilite des melanges a tout d'abord ete evaluee en termes de vides interstitiels pour chaque condition de compaction (immediatement apres le melange ou apres 1 a 2 heures d'entreposage dans un four). La resistance des melanges a la densification et a la distorsion a ete examinee au moyen d'indices de compaction et d'indices de circulation. Les donnees montrent que la creation de mousse par l'ajout de zeolites atteignait une valeur maximale d'intensite apres 1 heure (de temps) de formation de micro-mousse. Une periode de temps plus longue semble annuler l'effet. Les resultats de cette etude devraient profiter aux professionnels et aux chercheurs. [Traduit par la Redaction] Mots-cles: asphaltes melanges a chaud, zeolite synthetique, maniabilite de l'asphalte, procede de formation de mousse, energie de compaction., Introduction The objectives of preserving the environmental quality, reducing the use of natural resources, and protecting human health, are fundamental in the aim of promoting the sustainable development. Industrial activities [...]

The usage of recycled asphalt shingles (RAS) in hot mix asphalt (HMA) pavements provides many benefits as long as they are properly engineered into the various HMA mixes. Contractors, consultants, and Departments of Transportation have evaluated the performance of these various materials, although they are still only used in a limited number of areas. Alternatively, recycled asphalt pavement (RAP) is recognized as a high value recycled material and is actually the most recycled material in North America. In Ontario, RAP is successfully used in most HMA. Related studies on HMA containing RAS and RAP are limited in Canada although recently studies and field trials on effectively using RAS in HMA in Ontario have been completed by the Centre of Pavement and Transportation Technology (CPATT) at University of Waterloo in partnership with Miller Paving Ltd and the Ontario Centre of Excellence. This paper presents key findings from a comprehensive laboratory investigation and analysis of six asphalt mixes with RAS and RAP in Ontario through dynamic modulus, resilient modulus, thermal stress restrained specimen, and flexural fatigue testing. Using RAS alone or combining with RAP makes the asphalt stiffer at high and low temperatures respectively. Lowering the low temperature performance grade of the asphalt binder by 6 °C and incorporating 3% RAS or less with RAP in HMA mix design can result in meeting the appropriate specification. While field testing of RAS pavements demonstrated that surface friction properties are in good condition in various environmental and loading conditions, the laboratory test results and field performances indicate that RAS can be a useful additive to asphalt mixes in Ontario hot mix pavement through reasonable mix design. Key words: hot mix asphalt, recycled asphalt shingles, recycled asphalt pavement, laboratory evaluation, field friction testing. L'utilisation de bardeaux en asphalte recycles dans les revetements en asphalte melange a chaud fournit plusieurs avantages en autant qu'on en tienne adequatement compte dans les divers melanges d'asphalte melanges a chaud. Les entrepreneurs, les consultants et les ministeres des transports ont evalue le rendement de ces divers materiaux, bien qu'ils ne soient utilises que dans un nombre restreint d'endroits. Par contre, le revetement en asphalte recycle est reconnu etre un materiel recycle de valeur et il est presentement le materiel le plus recycle en Amerique du Nord. En Ontario, le revetement en asphalte recycle est utilise avec succes dans la majorite des asphaltes melanges a chaud. Au Canada, le nombre d'etudes pertinentes sur les asphaltes melanges a chaud contenant des bardeaux d'asphalte recycles et du revetement en asphalte recycle est limite, bien que des etudes recentes et des essais sur le terrain utilisant des bardeaux en asphalte recycles dans les asphaltes melanges a chaud en Ontario aient ete realisees par le Centre of Pavement and Transportation Technology (CPATT) de l'Universite de Waterloo en partenariat avec Miller Paving Ltd. et le Centre d'excellence de l'Ontario. Cetarticle presente les principales conclusions d'une etude complete en laboratoire et d'une analyse de six melanges asphaltiques contenant des bardeaux d'asphalte recycles et du revetement en asphalte recycle en Ontario; les essais portaient sur : le module dynamique, le module de resilience, le retrait thermique empeche et des essais de fatigue en flexion. L'utilisation unique de bardeaux en asphalte recycles ou en les combinant avec les revetements en asphalte recycle rend l'asphalte plus rigide a des temperatures respectivement elevees et basses. Le fait d'abaisser la temperature de la classe du liant asphaltique de 6 °C et d'incorporer 3 %, ou moins, de bardeaux en asphalte recycles a un revetement en asphalte recycle dans la conception des melanges asphaltiques a chaud peut permettre de rencontrer la specification appropriee. Bien que des essais sur le terrain des revetements contenant des bardeaux en asphalte recycles aient montre que les proprietes de friction de surface sont en bon etat sous diverses conditions environnementales et de chargement, les resultats des essais en laboratoire et les rendements sur le terrain indiquent que les bardeaux en asphalte recycles peuvent etre un ajout utile aux melanges asphaltiques a chaud en Ontario grace a une conception raisonnable des melanges. [Traduit par la Redaction] Mots-cles : asphalte melange a chaud, bardeaux en asphalte recycles, chaussee en asphalte recycle, evaluation en laboratoire, essais de friction sur le terrain., Introduction Generally, asphalt shingled roofs require replacement or recovering after 12 to 20 years. Each year, the roofing replacement of residential and commercial buildings generates 8 to 10 million tons [...]

This paper summarizes a research study that involved a partnership between Centre for Pavement and Transportation Technology located at University of Waterloo and Interlocking Concrete Pavement Institute. This research study involved the construction of eight crosswalks with different base and bedding materials at two test sites and was directed at defining the performance mechanics for designs with various bases and setting beds. The objective was to quantify the structural performance of four different interlocking concrete pavement designs under two loading scenarios. The Test Track typically experienced loaded garbage trucks up to 56 000 kg of maximum load. The Ring Road experienced traffic volume of a typical urban road. This research evaluated eight crosswalks of four different designs in these two locations. Sand set concrete base concrete header was one of the designs. Similarly, the combination of asphalt base, granular base, steel header, aluminum header, and concrete header were other designs of the crosswalks studied. Strain gauges, moisture probes, earth pressure cells, and thermistors were installed in the crosswalks to continuously monitor the structural and environmental impact from various loading conditions. Continued surveys were all performed as part of the research. Maximum recommended lifetime design equivalent single axle loads (ESALs) for bituminous set concrete base concrete header design was 7.5 million ESALs and sand set asphalt base asphalt header was recommended to have 1.5 million design ESALs. This paper presents the performance mechanics of the crosswalks from construction (2007-2009) to May 2010. Key words: interlocking, concrete, ICPI, crosswalks, pavers. Cet article resume une recherche impliquant un partenariat entre le CPATT (Centre for Pavement and Transportation Technology) situe a l'Universite de Waterloo et l'ICPI (Interlocking Concrete Pavement Institute). La recherche comportait la construction de huit passages pour pietons en utilisant divers materiaux de fondation et d'assise a deux sites d'essai; elle visait a definir la mecanique de rendement des conceptions ayant diverses fondations et diverses assises. L'objectif etait de quantifier le rendement structural de quatre types de paves autobloquants en beton sous deux scenarios de charge. La piste d'essai supportait normalement des camions de vidanges charges pesant un maximum de 56 000 kg. Le carrefour giratoire supportait un volume de circulation typique des routes urbaines. La presente recherche evaluait huit passages pour pietons de quatre conceptions differentes a ces deux sites d'essai. L'une des conceptions etait un rebord de beton avec une base de beton a assise de sable (SSCBCH--Sand Set Concrete Base Concrete Header). Les autres conceptions etudiees combinaient une base d'asphalte, une base granulaire, un rebord d'acier, un rebord d'aluminium et un rebord de beton. Des extensometres, des sondes d'humidite, des cellules de mesure des pressions du sol et des thermistances ont ete installes dans les passages pietonniers afin de surveiller en continu l'impact structural et environnemental des diverses conditions de chargement. Les releves en continu ont tous ete realises dans le cadre de cette recherche. La duree de vie maximale recommandee en charge equivalente par essieu simple (ESAL) pour la conception avec rebord de beton, base de beton et assise d'asphalte (BSCBCH--Bituminous Set Concrete Base Concrete Header) etait de 7,5 millions d'ESAL et de 1,5 million d'ESAL pour la conception avec rebord d'asphalte, base d'asphalte et assise de sable (SSABAH--Sand Set Asphalt Base Asphalt Header). Cet article presente la mecanique de rendement des passages pietonniers entre leur construction (2007- 2009) et mai 2010. [Traduit par la Redaction] Mots-cles: autobloquant, beton, ICPI, passage pour pietons, paves., Introduction The contributing partners to this research project were the Center for Pavement and Transportation Technology (CPATT) located at University of Waterloo (UW) and the Interlocking Concrete Pavement Institute (ICPI). [...]

Pervious concrete pavement (PCP) is an appropriate means to meet growing environmental demands. To apply pervious concrete as a pavement, its performance should be studied over its life span. This research aims to develop empirical performance models based on a proposed condition index through incorporation of integrated laboratory and field work. Since no condition index has been developed for PCP to date, first, a condition index is developed. The condition index is proposed as a combination of two indices: a surface distress index and a functional performance index. Two sources of data have been collected to develop performance models including panel rating and field investigations. Performance models are developed in two phases using regression analysis techniques. In phase I, performance models are presented as functions of a surface distress index and a functional performance index, while in phase II, performance models are correlated with pavement age and successfully validated. Key words: empirical performance modeling, pervious concrete. Une chaussee en beton permeable est un moyen approprie pour rencontrer les demandes environnementales croissantes. Pour utiliser le beton permeable comme chaussee, il faut en evaluer le rendement durant tout son cycle de vie. La presente recherche vise a developper des modeles de rendement empiriques bases sur un indice de condition qui a ete developpe en incorporant le travail de laboratoire et de terrain. Puisqu'aucun indice de condition n'a ete developpe a ce jour pour les chaussees en beton permeable, il faut d'abord developper un indice de condition. L'indice de condition est propose comme etant une combinaison de deux indices: un indice de degradation de la surface et un indice de rendement fonctionnel. Deux sources de donnees ont ete colligees afin de developper des modeles de rendement incluant la notation par un panel et des etudes sur le terrain. Les modeles de rendement ont ete developpes en deux phases utilisant des techniques d'analyse de regression. Dans la phase I, les modeles de rendement sont presentes en tant que fonctions d'un indice de degradation de la chaussee et d'un indice de rendement fonctionnel. Dans la phase II, les modeles de rendement sont correles al' age de la chaussee et valides avec succes. Mots-cles : modelisation du rendement empirique, beton permeable. [Traduit par la Redaction], Introduction Pervious concrete is a zero-slump, open graded material consisting of cement, coarse aggregate, little or no fine aggregate, admixture, and water. Pervious concrete pavement (PCP) is an appropriate means [...]

Wet pavement skidding due to inadequate surface texture or friction contributes to 20% to 35% of all wet weather crashes. Many of the past studies of pavement surface texture and friction have deficiency in selecting the model forms or variables and interpreting the models and (or) the findings or have recommended further investigation. These pose a challenge for the highway agencies in selecting the appropriate surface layer and (or) measuring tools. This study was undertaken to re-examine some of the pavement surface texture and skid resistance related issues and aid the highway agencies in this area. Pavement surface texture and skid resistance aspects were carefully examined using the data collected from nine asphalt concrete (AC) surfaces. Pavement surface texture was measured using the sand patch method and a high speed texture laser. Skid resistance was measured using a British Pendulum and a skid trailer. The analysis has reinstated that aggregate quality is the predominant factor for AC surface skid resistance. Both texture depth and ribbed tire skid resistance was shown to increase with an increase in coarse aggregate (CA) content proving their interdependency. Neither the voids in mineral aggregate (VMA) or air voids (AV) contents showed a meaningful or statistically significant correlation with the surface texture or skid resistance. Fairly good correlations were found among the British Pendulum number (BPN), ribbed tire skid number (SN) and mean texture depth (MTD) rejecting the hypothesis that BPN is a measure of only surface micro-texture and ribbed tire skid number is insensitive to surface texture. Key words: asphalt concrete, British Pendulum, mean profile depth, mean texture depth, mix constituents, skid number, surface texture. Le derapage sur chaussee mouillee en raison d'une texture ou un coefficient de frottement a la surface inadequat contribue a 20 %-35 % de tous les accidents par temps de pluie. Plusieurs etudes anterieures sur la texture et le coefficient de frottement des chaussees presentent des manques dans la selection des formes ou des variables des modeles et l'interpretation des modeles et/ou des conclusions ou encore recommandent de nouvelles etudes. Cela pose un defi aux ministeres des transports quant a la selection de la couche de surface et/ou des outils de mesure appropries. La presente etude a ete entreprise pour reexaminer certaines questions reliees a la texture de surface des chaussees et a la resistance au derapage et ainsi aider les ministeres des transports dans ce domaine. Les aspects de texture de surface des chaussees et de la resistance au derapage ont ete examines attentivement en utilisant les donnees colligees sur neuf surfaces de beton bitumineux. La texture de surface des chaussees a ete mesuree en utilisant la methode d'etalement de couches de sable et un laser pour mesurer la texture a haute vitesse. La resistance au derapage a ete mesuree en utilisant le pendule SRT (skid resistance tester) et une remorque de glissance. L'analyse a confirme que la qualite des agregats est le principal facteur de la resistance au dera-page des surfaces de betons bitumineux. La profondeur de la texture et la resistance au derapage des pneus nervures ont augmente avec l'augmentation du contenu en agregats grossiers, prouvant ainsi leur interdependance. Ni le pourcentage en vides dans les agregats mineraux ni le pourcentage en vides d' air ne presentent une correlation importante ou statistiquement significative avec la texture de la surface ou la resistance au derapage. De relativement bonnes correlations ont ete de-couvertes entre le BPN (British Pendulum number), un indice de glissance des pneus nervures (SN--skid number) et la profondeur moyenne de la texture rejetant l'hypothese que le BPN ne soit qu'une mesure de la microtexture de la surface et que l' indice de glissance des pneus nervures est independant de la texture de la surface. Mots-cles : beton bitumineux, pendule SRT, profondeur moyenne du profile, profondeur moyenne de la texture, composants mixtes, coefficient de derapage, texture de surface. [Traduit par la Redaction], Introduction The main purpose of a transportation system is to facilitate safe and efficient movement of people and goods. However, over one million people die and fifty million are injured [...]

Pervious concrete pavement offers sustainable solutions to urban growth challenges by providing a stormwater management alternative and benefits to the ecosystem and community. Maintenance may not always be required but is likely needed in general to maintain adequate performance of pervious concrete. A Canada wide study has been initiated to evaluate the performance of pervious concrete pavement in the Canadian freeze-thaw climate. This paper presents the results to date related to the work that has been performed in evaluating maintenance methods at five field sites across Canada. In general, the results indicate that it is essential to agitate the debris in the voids to remove and clear as much material as possible. The maintenance methods that have been evaluated are the following: sweeping using a broom or street sweeper; rinsing the surface with a garden hose or large hose; vacuuming; and power washing. Key words: pervious concrete pavement, field site performance, permeability renewal maintenance techniques. Une chaussee en beton permeable offre des solutions durables aux defis de la croissance urbaine en fournissant une alternative a la gestion des eaux pluviales; elle offre egalement des avantages pour l'ecosysteme et la communaute. La maintenance du beton permeable n'est pas toujours requise mais sera probablement necessaire en general pour maintenir un rendement adequat. Une etude a la grandeur du Canada a ete entreprise pour evaluer le rendement des chaussees en beton permeable dans le climat canadien de cycles de gel-degel. Cet article presente les resultats a ce jour du travail realise dans revaluation des methodes de maintenance a cinq endroits au Canada. Regle generale, les resultats indiquent qu'il est essentiel d'agiter les debris dans les vides afin de retirer et d'eliminer autant de materiel que possible. Les methodes de maintenance evaluees sont les suivantes: balayage utilisant un balai ou une balayeuse de voirie; rincer la surface avec un boyau d' arrosage ou une lance a eau; aspirer; et lavage a la pression. Mots-cles: chaussee en beton permeable, rendement sur le terrain, techniques de maintenance de renouvellement de la permeabilite. [Traduit par la Redaction], Introduction Pervious concrete pavement is a concrete paving material with up to 30% void content. The void content is developed in the mix by limiting the fine aggregate content. The [...]

Pavement surface friction is an essential attribute of highway safety. The desired surface friction should also accommodate the seasonal and long-term variations. The available surface friction depends mainly on microtexture and macrotexture on pavement surfaces. An increased surface texture for increased and durable friction may increase the roadway noise, which is also a growing problem. Traditional sound barriers, constructed to reduce noise exposure, are very expensive. As the pavement surface characteristics play a key role in roadway noise generation, it provides a window for noise reduction by altering the pavement surface. The challenge, however, is to provide a smooth, quiet, long-lasting, and economic pavement with adequate and durable surface friction. This paper addresses this challenge and provides a realistic guideline. The correlation of tire-road noise and surface friction is examined using data collected from five different asphalt pavements. Frameworks for desired minimum surface friction and maximum roadway noise are provided. A modified value-engineering approach is proposed to accommodate the construction and maintenance costs, longevity, smoothness, safety, and noise in the selection of pavement surfaces. Key words: surface texture, surface friction, highway safety, roadway noise, optimization, pavement management. Le coefficient de frottement a la surface de la chaussee est un attribut primordial en securite routiere. Le coefficient de frottement desiree devrait egalement tenir compte des variations saisonnieres et a long terme. Le coefficient de frottement disponible depend principalement de la micro texture et de la macro texture de la surface des chaussees. Une texture accrue de la surface visant a accroitre la friction et la durabilite peut egalement accroitre le bruit de la route, ce qui represente egalement un probleme croissant. Les murs coupe-sons construits pour reduire l'exposition au bruit, sont tres dispendieux. Puisque les caracteeristiques de surface des chaussees jouent un role important dans la production de bruit de la route, il est maintenant possible de reduire le bruit en modifiant la surface de la chaussee. Le deefi est de fournir une chaussee lisse, silencieuse, qui dure longtemps et qui est economique en plus d'offrir un coefficient de frottement adequat et durable. Cet article traite de ce deefi et fournit des lignes directrices realistes. La correlation entre le pneu, le bruit de la route et le coefficient de frottement est examinee en utilisant des donnees provenant de cinq chaussees bitumineuses differentes. Les cadres pour obtenir le coefficient de frottement minimum requis et le seuil maximum de bruit de la route sont fournis. Une approche modifiee d'ingeenierie de la valeur est proposee afin de tenir compte des couts de construction et de maintenance, de la longevite, de la rugosite, de la securite; et du bruit dans la selection des surfaces de chaussees. Mots-cles: texture de surface, coefficient de frottement, securite; routiere, bruit de la route, optimisation, gestion des chaussees. [Traduit par la Redaction], Introduction Over one million people die and 50 million are injured annually from highway crashes around the world (Snyder 2006). Several factors, including driver skill and behaviour, roadway design elements [...]

Traffic noise is a growing problem throughout the world. Noise barriers, traditionally used for reducing noise exposure, are expensive and inefficient in some cases. Pavement surface characteristics play a key role in noise generation and propagation. Information about noise-reducing characteristics of various Portland cement concrete (PCC) and asphalt concrete (AC) pavements can therefore help public agencies in selecting an appropriate surface that maximizes the structural durability, reduces the noise, and ensures adequate skid resistance for safety. In this study, tire-pavement close proximity (CPX), in-vehicle, and controlled pass-by (CPB) noise were measured at 80-100 km/h for 32 PCC and AC pavements in southern Ontario. The results have indicated that certain textures are needed to allow for air escape from the tire-road interface, which limits the generation and (or) propagation of tire-pavement noise. Both fine-graded Superpave and stone mastic asphalt (SMA) were shown to be promising for noise reduction and have good durability characteristics. However, careful placement and finishing are essential to produce a uniform lower order macrotexture and to attain the noise-reduction benefit. Key words: traffic noise, tire-pavement noise, close-proximity noise, in-vehicle noise, controlled pass-by noise, noise-reducing pavements. Le bruit de la circulation est un probleme croissant dans le monde entier. Les ouvrages antibruit traditionnellement utilises pour reduire l&apos;exposition au bruit sont dispendieux et inefficaces dans certains cas. Les caracteristiques de la surface du revetement jouent un role preponderant dans la generation et la propagation du bruit. L&apos;information sur les caracteristiques d&apos;attenuation du bruit de divers revetements en beeton de ciment Portland (<< PCC >>) et en beeton bitumineux (<< AC >>) peut donc aider les agences publiques a choisir une surface appropriee qui maximise la durabilite structurale, reduit le bruit et assure une antiderapance adequate pour la securite. Dans la presente etude, le bruit a proximite immediate pneu-revetement (<< CPX >>), a bord du vehicule et de passage controle (<< CPB >>) a ete mesure de 80 km/h jusqu&apos;a 100 km/h pour 32 revetements PCC et AC dans le sud de l&apos;Ontario. Les resultats montrent que certaines textures sont requises afin de permettre a l&apos;air de s&apos;echapper de l&apos;interface pneu-chaussee, ce qui limite la generation et (ou) la propagation du bruit pneu-revetement. Le Superpave a grains fins et l&apos;enrobe grenu a forte teneur en mastic montrent une attenuation du bruit prometteuse en plus de bonnes caracteristiques de durabilite;. Toutefois, une pose et une finition soignees sont essentielles pour produire une macro-texture uniforme d&apos;ordre inferieur et obtenir l&apos;avantage d&apos;attenuation du bruit. Mots-cles: bruit de la circulation, bruit pneu-revetement, bruit de proximite immediate, bruit a bord du vehicule, bruit de passage controie, revetements attenuateurs de bruit., Introduction Noise is an environmental pollutant that affects both public health and the economy. A nationwide survey indicated that half of Canadians are bothered, disturbed or annoyed by noise originating [...]

Development of an adequate performance model based on an appropriate condition index has been a major challenge for engineers particularly in case of a new type of design such as pervious concrete pavement structures (PCPSs) which suffer from limited long term performance data sets especially in colder climates. Soft computing techniques are significantly efficient at dealing with subjective, incomplete, and limited data. This paper proposes three most effective soft computing methods: fuzzy sets, the Latin Hypercube Simulation technique, and the Markov Chain process. A novel comprehensive condition index based on severity, density, and weighting factors of distresses occurring on PCPS has been developed incorporating fuzzy sets. A combination of homogeneous and nonhomogeneous Markov Chain has been applied to develop performance models. Transition probability matrices are presented using probability distribution functions rather than single values. A simulation technique is then used to incorporate the probability distribution function operations to compute the future condition of the pavements. The future performance of the pavements is expressed by both single expected values and suitable probability distribution functions. Ultimately, a probabilistic versus deterministic performance curve is presented. DOI: 10.1061/(ASCE)TE. 1943-5436.0000052 CE Database subject headings: Markov process; Fuzzy sets; Simulation; Concrete pavements; Cold regions; Computer applications.

Two types of analysis were conducted to examine the impacts of midcentury scenarios of anthropogenic climate change on flexible pavement infrastructure in southern Canada. An analysis of deterioration-relevant climate indicators at 17 southern Canadian sites revealed that over the next 50 years low temperature cracking will become less problematic, structures will freeze later and thaw earlier with correspondingly shorter freeze season lengths, and higher extreme in-service pavement temperatures will raise the potential for rutting. Pavement performance simulations conducted using the mechanistic-empirical pavement design guide and data from the Canadian long term pavement performance program for six of these sites also suggest that rutting issues will be exacerbated by climate change and that maintenance, rehabilitation, or reconstruction will be required earlier in the design life. While the simulated effect of climate change was found to be modest, both in absolute terms and relative to variability in pavement structure and baseline traffic loads, pavement engineers would benefit by incorporating longer time series of weather and climate in their designs. Although the analysis was conducted for southern Canada, many of the findings and impacts may be similar for the northern United States. DOI: 10.1061/(ASCE)0733-947X(2009) 135:10(773) CE Database subject headings: Canada; Climatic changes; Pavement design; Asphalt pavements; Pavement management; Flexible pavements.

Since the use of pervious concrete pavement structures (PCPSs) is essentially still in the trial stage in Canada, long-term and quantitative pavement condition data are not available. The existing approaches applied to assess pervious concrete pavement structure (PCPS) conditions are ad hoc and suffer from methodological limitations. A fuzzy set technique is proposed herein as an efficient tool for dealing with qualitative and incomplete pavement condition data on distress types, severities, densities, and weighting factors. Using this method, a comprehensive fuzzy condition index was developed based on Ministry of Transportation of Ontario (MTO) methodology and using fuzzy pavement condition data. This fuzzy condition index was converted to a single value that allowed for comparisons of pavement conditions using several ranking techniques. A case study of 24 PCPS sites was utilized to demonstrate how the fuzzy representations of the condition index compared with associated single values. It is shown that this approach can effectively provide extensive condition indices for PCPSs and rank them accordingly, using only limited and imprecise pavement condition data. Key words: fuzzy set, pavement condition index, pervious concrete pavement. Etant donne que les structures de chaussees en beton permeable (' PCPS ') sont encore essentiellement a l'essai an Canada, il n'existe pas de donnees quantitatives et a long terme disponibles sur 1'6tat des chaussees. Les approches actuelles utilisees pour evaluer l'etat des ' PCPS ' sont ponctuelles et leur methodologie est limitee. La technique des ensembles flous est presentee ici comme un outil efficace pour faire face aux donnees qualitatives incompletes sur l'etat des chaussees (c.-a-d. facteurs de gravit6, de densite et de ponderation des dommages). Un indice flou complet de l'etat est ensuite developpe base sur une methode du ministere des Transports de l'Ontario (' MTO ') et sur les donnees floues de l'etat des chaussees. L'indice flou de l'etat est converti en une valeur unique incorporant plusieurs techniques de classement afin de pouvoir comparer l'etat de diverses chaussees. Une etude de cas (comportant 24 sites ' PCPS ') est utilisee afro de demontrer les representations floues de l'indice de l'etat et de comparer les valeurs uniques connexes. Il est demontre que cette approche pent fournir un indice complet effectif de 1'etat des ' PCPS ' et les classer en se basant sur des donnees limitees et imprecises de l'etat des chaussees. Mots-cles : ensemble flou, indice de l'etat des chaussees, chaussees en beton permeable. [Traduit par la Redaction], Introduction Pervious concrete is undoubtedly a novel type of sustainable pavement, particularly in colder climates. It is capable of being in service while incurring only minimal long-term effects on the [...]

Abstract: Concrete pavements are well known for long structural life. The major challenge, however, is to provide a durable surface with adequate skid resistance for economy and safety. This paper [...]

Abstract: To make appropriate decisions on overload limits of various axle configurations that can be endorsed for routine permitting, highway agencies need to understand the impact of these axle groups [...]