Moisture Damage Evaluation in Carbon Nanotubes Reinforced Asphalts KH. Al-Adham 1, a & MD Arifuzzaman 2,b 1 Graduate M.Sc. Student, Dept. of Civil & Environmental Eng., KFUPM, Saudi Arabia 2 Assistant Professor, Dept. of Civil & Environmental Eng., KFUPM, Saudi Arabia a g201203180@kfupm.edu.sa, b arifz@ kfupm.edu.sa ABSTRACT: The main objective of this paper is to investigate the new properties of asphalt binders reinforced with Carbon Nano Tubes (CNT), There are two types of structure of nanotubes used; Single and Double wall tubes. This mixture was tested and gave remarkable results using Atomic Force Microscope (AFM) testing technique. Results of the laboratory evaluation in this study indicated that when adding 1.5% of (CNT) to asphalt, the adhesive forces become higher than using styrene-butadiene-styrene (SBS) polymers, Also, the wet conditions of sampling show higher values of adhesion forces than the dry conditions when using NH 3 and COOH tips. This leads to the conclusion that using CNT increases the moisture susceptibility of asphalt binders. 1. INTRODUCTION Recently, many attempts were used by researchers to study the asphalt binders and their properties, and thus the adhesion force between binders and aggregate in the mixture. The utilization of this improvement is a practice to decrease the moisture damage of asphalt in wet conditions. Moisture damage in asphalt has been investigated for many years using different types of antistripping agents. However, it remains an unsolved problem till today and it seems that traditional macro scale tests and methods are not adequate to elaborate on the moisture damage phenomenon. Moisture damage in asphalt is mostly related to asphalt chemistry and adhesion characteristics, which are below the micron scale phenomena. In this study, asphalt chemistry and adhesion values were studied at nanoscale to understand moisture damage for modified asphalts mixed with Carbon Nanotubes (CNT), which is one of the state-of-the-art materials used to improve the properties of any structure. Carbon nanotubes are molecular graphitic carbon tubes that posses remarkable properties. They are one of the strongest and stiffest materials ever tested with asphalt binders, and also have remarkable electronic properties that can help while using Atomic Force Microscope (AFM) test. Many industrial and academic intrests have been attracted to these marterials and hundresds of papers on nanotubes being published every year. However, the production cost of the best quality nanotubes is very high and that reduces the commercial applications of this new material. All nanoscale measurements and experiments are conducted using the AFM. In an (AFM) test, adhesion forces of dry, wet and aged asphalt samples are measured by investigating the sample surface with AFM tips. Nanoscale adhesion pull- off force between sample molecules and tip molecules are measured in nano newton (nN). To facilitate the study of asphalt chemistry, AFM tips are modified using chemical functional groups such as carboxyl (ــCOOH), hydroxyl (ــOH), ammin (ــNH 3 ) and methyl (ــCH 3 ), representing the chemistry of asphalt binder (Arifuzzaman and Tarefder, 2013). 2. MATERIAL DESCRIPTION The name of Carbon Nanotube (CNT) was taken from its hollow and long structure that combined with thick sheets of carbon that consists of one atom. These sheets are called graphene as shown in Fig. 1. The sheets of graphene are rolled at specific angles, and the properties of nanotubes are decided by the combination of the radius and rolling angle. Some types of carbon nano tubes have been constructed with diameter to length (D/L) ratio of up to 1/132,000,000. These carbon molecules have remarkable physical and chemical