During last decade, researchers’ interest in nanotechnology applications, particularly in the field of pavement materials, has been increasing. This research work focused on the investigation of the properties of asphalt binder modified with different percentages of two different nanomaterials. These materials are nanoclay, and nanosilica. The nanosilica was manufactured from two different sources: silica fume and rice husk. Nanomaterials and asphalt binder were first characterized. A mechanical mixer was then used at 1500rpm to mix the nanomaterials with the binder. Required mixing time was determined. Three different nanomaterial percentages were mixed with the binder. The modified binders were tested for rheological properties. Results showed that, nanosilica synthesized from silica fume tends to decrease the penetration value and increase the softening point temperature. The nanoclay on the other hand was found to increase the penetration and decrease the softening point temperature. At temperature of 135°C and up to 150°C, increasing nanosilica percentage was found to increase Brookfield Rotational Viscosity (RV), while nanoclay, at small percentages, increased the RV and then decreased it at higher percentages. At higher temperature, up to 165°C, the RV values did not change significantly using both nanomodifiers. Nanosilica from rice husk showed improvement in the RV results. Finally, the Dynamic Shear Rheometer (DSR) results showed obvious improvement in the performance grade leading to higher resistance to permanent deformation

Pavements are subjected to many distresses during their service lives. One of the main distresses that a pavement is subjected to is rutting. This paper focuses on the effect of using a fine or coarse gradation, as related to the restricted zone, on the rutting behaviour of asphalt concrete in flexible pavements. The restricted zone was one of the Superpave gradation selection criteria. This was done through traffic-simulated dynamic testing programme of asphalt concrete made of Egyptian materials. The Ohio state model as one of the models that could be used in predicting rutting was employed in this research. The model relates rutting to the resilient and residual properties of the pavement. The experimental results were analysed according to that model. It was found that fine gradations, passing above the restricted zone, were more susceptible to rutting especially for higher deviator stress.

This paper focused on predicting the performance of asphalt mixes modified with nano-montmorillonite (NMMT) and nano silicon dioxide (NSD) using the Quality-Related Specifications Software (QRSS), which is a simplification to the Pavement ME Design. The nanomaterials were thoroughly mixed with the binder at a temperature of 145 ± 5°C. The conventional and the rheological properties were determined for the penetration grade 60–70 control binder as well as binders modified by 3, 5 and 7% of NMMT and NSD by the weight of asphalt. The optimum nanomaterial content was found for each modifier and was then used for preparing asphalt mixtures by the conventional Marshall method. Finally, Witczak 1-40D complex shear modulus (G*) based predictive model was used to estimate the dynamic modulus (E*) for the control and nanomodified asphalt mixtures. The field performance in terms of asphalt concrete (AC) layer rutting and fatigue cracking was predicted using the QRSS software for two typical pavement sections and three different climatic locations in Egypt (Alexandria, Cairo and Aswan). The simulation runs revealed that both nanomodified asphalt mixtures exhibited superior pavement performance in terms of AC rutting compared to the control mix without a significant effect on fatigue life.

The implementation of the new mechanistic-empirical design guide has led to the need for more accurate inputs. One of the most important inputs that affect the performance of the pavement materials is the climatic data. The importance of accurate climatic data is investigated in this case study. Climatic files available with the design guide and ones developed based on historical information for counties in the state of Iowa through the Iowa Environmental Mesonet were used. The climatic files that were interpolated from the data available within the design guide predicted higher rutting (both total and asphalt cement layer) for the northern part of the state, lower thermal cracking, and lower international roughness index compared to the files developed in this study. Statistical analysis showed that the results calculated using both groups are different.