Various models have been developed over the past several decades to predict the dynamic modulus /E*/ of hot-mix asphalt (HMA) based on regression analysis of laboratory measurements. The models most widely used in the asphalt community today are the Witczak 1999 and 2006 predictive models. Although the overall predictive accuracies for these existing models as reported by their developers are q...

Using a rejuvenator to improve the performance of asphalt pavement is an effective and economic way of hot asphalt recycling. This research analyzes the rejuvenating effect on aged asphalt by means of a Mortar Transfer Ratio (MTR) test, which concerns the ratio of asphalt mortar that moves from recycled aggregates (RAP aggregates) to fresh added aggregates when aged asphalt is treated with a re...

Reducing start and stop time without destroying the pavement surface is important in enhancing productivity of double-drum roller and compact quality of asphalt pavement, but it is difficult in confirming the maximum brake deceleration or start acceleration of double-drum roller. Dynamic analysis is used in studying these questions, and a mathematic model of double-drum roller is established, b...

The bearing capacity and service life of a pavement are adversely affected by the presence of undrained water in the pavement layers. In cold winter climates, such as in Iowa, this problem is magnified further by the risk of frost damage when water is present. Therefore, wellperforming subsurface drainage systems form an important aspect of pavement design by the Iowa Department of Transportati...

this paper identifies eleven types of asphalt pavement distress types, commonly occuring in tehran metropolitan area. of these, five distresses namely: corrugation; utility cut depression ;pot holes; alligator cracking; and loss of bridge deck surfacing are rather common. however, others namely: shear failure; shrinkage cracks; lane joint cracks; bleeding; and shoulder distress are less prevail...

Using nano-technology materials in the asphalt pavement industry is new compared with Portland cement concrete. The main objective of this study is to investigate the effects of nano-silica modification on some properties of a penetration grade asphalt cement and a typical asphalt concrete. 60/70 penetration grade bitumen was modified with different percentages of nano-silica (i.e. 1, 3 and 5%,...

This article is dedicated to the development of a joint filler for cracks in asphalt concrete pavement, as well expansion joints cement pavement. The presents choice unified units and unit being developed pavement Some methods calculating main parameters created are presented. In addition, suitable prototype filler, were selected from several types.

creep compliance is one of the fundamental tests of mechanistic- empirical flexible pavement design procedure in the aashto 2002 design guide. in this research, a new artificial neural network model for estimating the hma creep compliance with the generalization ability of r=0.949 has been developed successfully using feed forward multi layer perceptron artificial neural networks (anns) with le...

Asphalt fiber synchronous surface dressing has good stress absorption and dispersion ability. It a network winding structure, which can effectively absorb, diffuse redistribute the local concentrated in pavement reduce structure. reduces generation of cracks structure layer, prevents suppresses occurrence reflection cracks. For three consecutive years, Qingyang highway development center Gansu ...