Pavement performance

Durability. The term "durable" has several meanings, but in the present context it is used to describe an asphalt that possesses the necessary chemical and physical properties required for the specified pavement performance, being resistant to change during the in-service conditions that are prevalent during the life of the pavement. 

The mix proportions for concrete paving mixtures are determined by attaining optimum characteristics of the mix in both the plastic and hardened states. The designed mixture can be properly placed and consolidated, finished to the required texture and smoothness, and will have the desired properties necessary for pavement performance. Concrete paving mixtures should be... 

The driving force behind the commercial acceptance of sulphur extended asphalts is the cost reduction potential. Improved pavement performance, while of importance, is a secondary consideration. AC prices have been soaring recently in tandem with crude oil prices and continued rapid price escalation is forecast together with geographic shortages of asphalt. In many parts of North America a partial substitution of asphalt by sulphur will result in a reduction in cost per tonne of hot mix, and of course the use of sulphur will offset asphalt shortages (of up to 27%), wherever these shortages may occur. 

Sulfur-Asphalt Paying Materials (1J, ). Two different technologies are used to combine asphalt and sulfur into a binder that exhibits unique properties and often enhance the pavement performance as well as extend the supply of available asphalt. 

All above-mentioned tests are relatively rapid methods. The method(s) that is (are) most predictive of pavement performance will be employed for fiirther development of a test method for measurement of the adhesion properties between the asphalt and the aggregate surface. 

MacFarlane, I.C., and Rutka, A. 1962. An evaluation of pavement performance over muskeg in Northern Ontario. National Research Coimcil, Ontario, Canada. 

A recent study concluded that the bending beam rheometer test on bituminous binders is a vital tool that can be used to control pavement performance at low temperatures (Romero et al. 2011). In the same report, a draft specification was presented along with examples to demonstrate how the BBR test procedure can be adopted to facilitate quality control/quality acceptance operations in asphalt construction. 

Finn F.N., C.L. Monismith, and N.J. Markevich. 1983. Pavement performance and asphalt concrete mix design. Proceedings of the Association of Asphalt Paving technologists, Vol. 52, p. 121. 

Pais J., S. Amorin, and M. Minhoto. 2013. Impact of traffic overload on road pavement performance. Journal of Transportation Engineering, Vol. 139, No. 9, pp. 873-879. ASCE. 

In contrast to all other design methodologies for flexible pavements, the AASHTO methodology uses a pavement performance criterion, which, apart from cracking and subgrade deformation, includes other parameters affecting the performance of the pavement. This criterion is called serviceability, expressed as present serviceability index (PSI). 

Pavement performance criteria related to the user belong to the second category. These criteria are expressed in terms of initial PSI, p and terminal PSI, p. ... 

For a given reliability level, R, the reliability factor is a function of the overall standard deviation, S , which accounts for both change variation in the traffic prediction and normal variation in pavement performance prediction for a given design traffic. The standard deviation selected should be representative of the local conditions. 

The pavement performance criterion, which is taken into account in this methodology, is the pavement serviceability level. 

Regarding the environmental factors, subgrade moisture and temperature have been considered to significantly affect pavement performance. Freeze/thaw conditions were not considered since, as stated, they rarely occur in Australia. 

Highways Agency (2008a) also recommends that asphalt overlay design should not be based on deflection data alone, since deflectograph analysis does not take into account all factors related to pavement performance. 

Kennedy C. K. and N.W. Lister. 1978. Prediction of pavement performance and the design of overlays. TRRL Report LR 833. Crowthorne, UK Transport Research Laboratory. 

The central deflection, dl, gives an indication of the overall pavement performance whilst the deflection difference (dl-d4) relates to the condition of the bound pavement layers. Deflection d6 is an indication of subgrade condition (see also Figure 16.46, deflection bowl). 

The decisions are made by senior executives. As it is stated (Asphalt Institute 2009), they make decisions that play a part in determining pavement performance targets, distributing funds among regions or districts and establishing pavement preservation policies. Figure 17.2 illustrates the elements contained at the network level. 

The history of post-construction works, if carried out, must be known in detail. This provides valuable information on estimating rates of deterioration for locally existent conditions. Initial construction details and history of post-construction works link the differences in pavement performance to pavement structure characteristics. 

To support the analysis and prior optimisation, some parameters must be established. The most common ones are the pavement performance models, the treatment rules, the impact rules and cost information. 

The pavement performance or pavement deterioration models predict future changes in the pavement condition. They are critical because they determine when maintenance/ rehabilitation will be required, hence estimating needs for future funding. Thus, pavement performance prediction models should be as reliable as possible. 

The selection of recycling method depends on various factors such as pavement condition, road category, traffic volume, age of pavement, past interventions, availability of equipment/ machinery, expected pavement performance after recycling, cost and energy saving achieved. Selecting the most appropriate recycling method is not an easy task, since many parameters, which vary from one project to another, are involved. 

The issues addressed were specification and durability of asphalt pavements (approximately 50 million), long-term pavement performance ( 50 million), highway maintenance (about 10 million), winter maintenance ( 10 million), concrete ( 10 million) and structures ( 10 million). SHRP started its first contracts in September 1987 and completed its research at the end of 1993. 

The Strategic Highway Research Program (SHRP) was a five-year program that started in 1987. It was administered as a unit of the National Research Council. SHRP conducted accelerated research on a short list of priority research topics asphalt concrete and structures, highway operations and pavement performance. The following reports and videos are interim reports or reports expected to be of interest principally to researchers rather than practitioners thus, they have not been published. 

Burmister, D. M. 1967. Applications of dimensional analyses in the evaluation of asphalt pavement performances, Paper for presentation at Fifth Paving Conference, Albuquerque, NM. 

As shown in Fig. 11.7 field investigations are ongoing as to pavement performance in a number of locations. 

Base reinforcement thus improves long-term structural support for the base materials and reduces permanent deformation in the roadway section. Under certain conditions it has been found to provide significant improvement in pavement performance. 

NCHRP, 2011. NCHRP 01-50-Quantifying the Influence of Geosynthetics on Pavement Performance, the National Cooperative Highway Research Program. Transportation Research Board, Washington, DC. http //www.trb.org/CRP/NCHRP/NCHRPProjects.asp. 

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