Name: Hassan Divandari
Department: Engineering
Faculty: Construction
Academic Rank: Assistant Professor
Email: d i v a n d a r i @ i a u n s . a c . i r
Telephone: 09359351153
Postal Address: Islamic Azad University, Nowshahr Branch - Postal Code: 4651141433


Degree: Field: University: Country: Graduated Year:

Journal Articles
Publication Date 
Field Evaluation of Nondestructive Tests in Measuring the Pavement Layers DensityHassan ziari, Hamid Behbahani, Amir Izadi, Hassan Divandari10/22/2010
Conference -
Journal Journal of Applied Science
Volume 10
Pages 3091-3097
Publisher Asian Network of Scientific Information
Description One of the most applicable methods to control the quality of performed pavements is to measure asphalt concrete and granular layers densities. Determining asphalt mixture density while compaction and after finishing it, is important from compaction ratio and project accomplishment time aspects. The most common and precise method of measuring asphalt mixture density in situ is using cores. It is done by coring from asphalt mixture and performing density test on these samples in laboratory. The problem with this method is being destructive, expensive and results cannot be validated by repeating the test for a specific point while a lot of time is needed for a full project. The last problem makes it impossible to recognize bad compaction condition of layer and perform modifications on time. Using nondestructive density determination tests turned popular so much in recent years. These tests don’t destroy pavement, are less expansive than core method and are repeatable since can be used in a specific point for several times. Nondestructive test are divided to nuclear and non-nuclear tests. Nuclear device is used to determine density and moisture content in site based on ASTM D2922 – D3017 which is rapid and nondestructive. Gamma ray and Neutron particles are used in this device for determining density and moisture content respectively. On the other hand, radioactive substances which are radiated from these devices are the most important problem with them. Non-Nuclear NDT devices has the advantages of nuclear instruments while hasn’t the noticed problem. In this research electromagnetic PQI301 and nuclear Troxler HS-5001EZ device is evaluated in the field. Firstly the devices were calibrated and after that, 60 points in Tehran-Pardis freeway were selected in a lane with 3.65 width and at a spacing of 7 meters, each section divided to 6 parts and 10 sections were chosen totally. Both nuclear and nonnuclear devised were used for determining density of each point and for each group, one core were excavated and density were measured too. For granular layers, a detour for Latian Dam Road was selected and density determination were performed by sand bottle method and nuclear device. SPSS software was used to analyze the results of study. It was concluded PQI is useful in determining asphalt layer density, while nuclear device isn’t appropriate in measuring asphalt mixture density and it is convenience in determining granular layers density. It should be noted PQI is a good device to determine points with low compaction, even in pavement edges. Since density in edge of roller path is less than this parameter exactly under roller, quality control points should be selected not from edge points, otherwise the results contain a considerable error.
Development of experimental model to investigate the influences of the numbers and duration of heating of bitumen on penetration indexHasan Ziari, Hasan Divandari, Mohammad Kashani Novin12/6/2011
Conference 10th Annual International Conference on Sustainable Construction and Pavement Engineering
Publisher Liverpool John Moores University
Description A weakness point of bitumen is alteration of its useful properties after heating and cooling cycles. On the other hand, the duration of heating can effect on these characteristics adversely. In this paper, changes in bitumen characteristics, naming penetration, softening point and penetration index, under heating cycles and the alteration of the heating duration have been investigated. So, penetration and softening test have been conducted. The results show that the bitumen looses its characteristics dramatically under long and several heating cycle. Even in most cases, the bitumen group is changed and the bitumen looses its quality, what have to be incorporated in asphalt mix design. Finally, the six separated models have been developed to predict the amount of penetration, softening point and penetration index under two independent variables, number and duration of heating cycle of 60-70 and 85-100 bitumen.
Influence of Bentonite Additive on Bitumen and Asphalt Mixtures PropertiesZiari Hassan, Divandari Hassan, Babagoli Rezvan, Akbari Ali3/21/2012
Conference World Academy Of Science Engineering and Technology (WASE),
Publisher World Academy of Science, Engineering and Technology
Description Asphalt surfaces are exposed to various weather conditions and dynamic loading caused by passing trucks and vehicles. In such situations, asphalt cement shows so different rheological-mechanical behavior. If asphalt cement isn’t compatible enough, asphalt layer will be damaged immediately and expensive repairing procedures should be performed then. To overcome this problem, researchers study on mechanical improved asphalt cement. In this study, bentonite was used in order to modify bitumen characteristics and the modified bitumen's characteristics were investigated by asphalt cement tests. Then, the optimal bitumen content in various compounds was determined and asphalt samples with different contents of additives were prepared and tested. Results show using this kind of additive not only has caused improvement in bitumen mechanical properties, but also improvement in Marshall Parameters was achieved.
Developing a Forecasting Model for Asphalt Rutting Potential Using Gyratory Compactor ParametersHassan Ziari, Hassan Divandari, Hamid Behbahani, Mamoud Ameri9/28/2012
Conference -
Journal Life Science Journal
Volume 9
Issue 4
Pages 4140-4149
Description Rutting is one of the most important deteriorations in flexible pavements which a significant amount of maintenance and rehabilitation funds are consumed for repairing it annually. On the other hand lack of a simple test to determine specimen resistance to permanent deformation as the main reason for asphalt rutting is sensible in Superpave first level mix design which owes considerable advantages in comparison with the marshall method. Prevalent methods of evaluating rutting potential of asphalt mixtures are usually expensive and time consuming. Mentioned parameters illustrates the necessity of developing a simple method, not only having fine precision but also be able to predict specimens rutting performance in the short term in laboratory. In this research two types of aggregates (silica and calcareous base), two types of gradation, two types of bitumen, two types of filler and three bitumen contents were used to prepare specimens. After modeling gyratory shear stress, the model and gyratory compaction slope parameters were used to develop two mathematical models to estimate specimen wheel Track apparatus rut depth. These models were validated using ANN and GA and make it possible to evaluate rutting potential while preparing specimens in laboratory to determine optimum bitumen content. Hence not only expensive instruments for rutting test aren’t necessary but a considerable reduction in mix design procedure time is gained.
Presenting Asphalt Mixtures Flow Number Prediction Model Using Gyratory CurvesHassan Ziari, Hassan Divandari11/8/2013
Conference -
Journal International Journal of Civil Engineering
Volume 11
Issue 2
Pages 125-133
Publisher Iran University of Science and Technology (IUST)
Description Pavement permanent deformations due to lack of shear strength in mixture are a major reason of rutting. Any simple test to determine mixtures resistance to permanent deformation isn’t distinguished in the 1st level of SUPERPAVE mix design method and prevalent methods for evaluating mixture rut resistance are expensive and time-consuming. Two aggregate types, gradations, asphalt cements and filler types were used in this research to present a prediction model for rutting based on flow number. A mathematical model to estimate flow number of dynamic creep test was developed using model parameters and gyratory compaction slope. The model is validated using Neural Network and Genetic Algorithm and makes it possible to evaluate mixtures shear strength while optimum asphalt content is being determined in laboratory. So not only there is no need to expensive test instruments of rutting or dynamic creep but a remarkable time saving in mix design procedure is achievable.