gh.h hamedi

The pavement industry is one of the industries that has considered using waste to partially replace the aggregates in asphalt mixtures. Despite its many environmental and technical benefits, the use of crushed glass increases the moisture damage potential of asphalt mixtures. Therefore, in the present study, the aim was to investigate the effects of two nano anti-stripping additives called nano iron oxide (Fe2O3) and nano aluminum oxide (Al2O3) on the moisture susceptibility of hot mix asphalt (HMA) mixtures containing crushed glass. The glass asphalt mixtures were made by replacing 0, 5, 10, 15, and 20% of the fine aggregates with glass cullets. In order to investigate the effects of nano-materials on the moisture susceptibility of glass asphalt mixtures, the modified Lottman test (AASHTO T283) and the surface free energy (SFE) method were used. The results showed that the addition of nano-materials improved the adhesive force between asphalt binders and aggregates (crushed glass and aggregates with acidic properties) by reducing the acidic and increasing the basic properties of the modified asphalt binder. Moreover, asphalt modification with nano-materials increased the initial energy required to separate asphalt binder from the aggregate surface and reduced the risk of moisture damage by increasing the total SFE of asphalt binder.

Open graded asphalt is used as a wearing course to provide both increased safety inwet weather (through reduced surface water and spray during rain) and reduced noise levels. In thisstudy, Pumice aggregates were applied as a portion of fine aggregate for the improvement of dynamicalspecification of porous asphalt and the Cantabro, Los Angeles abrasion, and the bitumen precipitationtests were conducted. First, the amount of optimized bitumen related to each of the three types ofaggregates and fine Pumice has been estimated, then the properties of the Marshall Resistance andindirect tensile strength have been assigned. Mixtures with 5 percent of fine Pumice has shown bettercharacteristics in Marshall test as well as indirect tensile strength. Also, the results of dynamic creeptest showed that the rutting potential decreased by using Pumice aggregate. There is the best amount ofpermanent deformation for mixtures containing 5% Pumice

Liquid anti-stripping materials are the most popular materials used to improve moisture resistance of hot mix asphalt (HMA). In this study, the effect of two types of liquid anti-stripping materials (Wetfix N422 and Wetfix 312) with different percentages on the moisture susceptibility of HMA have been studied. HMA specimens with three types of aggregates (limestone, granite and quartzite) and two types of liquid anti-stripping materials are used in different percentages that are studied by modified Lottman test. In order to evaluate the effect of additive more accurately, 1, 3 and 5 freeze-thaw cycles are applied to the specimens. The results of this study indicate that the impact of additives used leads to the increased proportion of indirect tensile strength (ITS) in dry and wet conditions of HMA. The results of this study indicate that the additives used in this study increase tensile strength ratio (TSR) and the asphalt mixes’ resistance against moisture damage. In this study, the effect of anti-stripping additives in specimens under the wet conditions is more evident at higher freeze-thaw cycles compared to control specimens. In addition, the results show that the specimens prepared with limestone aggregate and Wetfix 312 additives have the highest TSR values.