Print ISSN: 1681-6900

Online ISSN: 2412-0758

Volume 31, Issue 21

Volume 31, Issue 21, December 2013, Page 11-564


Determining the Low Temperature Cracking of Local Asphalt Binder Using Asphalt Binder Cracking Device (Abcd)

Alaa Hussein Abed

Engineering and Technology Journal, 2013, Volume 31, Issue 21, Pages 444-452

Since asphalt binder is the most important factor that affects low-temperature cracking. It is imperative to know the critical cracking temperature in order to identify susceptible asphalts. The low temperature thermal cracking of asphalt pavements is one of the main causes for annually repeating expensive highway repairs. To determine the low-temperature cracking potential of the asphalt binder, asphalt binder cracking device (ABCD) was used. The operating principle of ABCD is based on the differential thermal contraction between the metal ABCD ring and an asphalt binder placed outside the ring, as the temperature is lowered, the test binder shrinks more rapidly than the ABCD ring placed inside, which lead to develop thermal stresses, when the thermal stress exceeds the strength of the binder, the binder specimen cracks. Strain gauges installed inside the ABCD ring detect the fracture, and the temperature is recorded as the ABCD cracking temperature. Four groups of local asphalt binders were used for this study; Daurah PG 64-16 (Pen 40-50) both rolling thin film oven (RTFO) and pressure aging vessel (PAV) aged , Daurah PG 58-22 (pen 85-100) RTFO and PAV aged, Baiji PG 64-16 (pen 40-50) RTFO and PAV aged, Basrah PG 64-16 (pen 40-50) RTFO and PAV aged. There is a fairly good agreement between ABCD results and Bending Beam Rheometer (BBR) in cracking temperature, for asphalt binder PG 64-16 the differences in cracking temperature about 6 o C, while for asphalt binder PG 58-22 there no significant differences. All the tests of local asphalt binders are done in the University of Wisconsin-Madison- USA.

Grain Size Distribution of the Self-Filtration Layer between the Base Soil and the Filter

Yousif A. H. Dallo; Yuan Wang

Engineering and Technology Journal, 2013, Volume 31, Issue 21, Pages 453-464

Some studies suggested a model to determine the grain size distribution GSD curve of the self-filtration layer that is formed at the base soil-filter interface. From these GSD curves the effectiveness of the filters is assessed assuming that the internal stability of the self-filtration layer reflects the effectiveness of the filter. In this paper a critical discussion to that method is presented. Also some essential modifications for the method are suggested. Finally, in disagreement with that method the applicability of usage of the GSD curve of the self-filtration layer to predict the effectiveness of the filter is found to be unreliable.

Studying the Properties of Cationic Emulsified Asphalts Paving Mixture at Iraqi Environmental Conditions

Shakir .A. Al-Mishhadani; Hasan. H. Al-Baidhani; Hussein Hamel Zghair

Engineering and Technology Journal, 2013, Volume 31, Issue 21, Pages 465-477

Emulsified asphalt mixture is generally a mix made of emulsified asphalt with aggregate. Emulsified asphalt is manufactured from base asphalt, emulsifier agent and water. This study aims to study and improve the emulsified asphalt mixtures with using of ordinary Portland cement as filler materials for road construction and maintenance in Iraq as an alternative to the hot asphalt mixtures, due to its economical, practical and environmental advantages. Beside this study focused to test and evaluates the emulsified asphalt material properties to be used as paving mixture. The tested properties of emulsified asphalt mixture were bulk density, air voids, dry Marshall Stability, wet Marshall Stability, retained Marshall Stability, flow tests with different compaction efforts differ from standard Marshall Limitations and compared with the common used specification. The results indicate that the emulsified asphalt type cationic slow setting low viscosity (CSS-1) is very suitable with quartz type of aggregate from Al-Nibaay quarry. From many trial mixes it is found that the best percentages of initial residual bitumen content to produced adequate results for coating test ,mixing ,compaction ,curing and Marshall stability were ranged from (2.5%, 3%,3.5%,4% and 4.5%), and the optimum percentage is (3.5%).Finally it can be conducted that the emulsified asphalt mixture contained Portland cement filler material is a suitable alternative mixture to the hot asphalt mixture for road construction and specially maintenance of roadways in Iraq.

Evaluation of Asphalt Pavement Using Ground Penetration Radar

Miami M. Hilal; Nawar A. Abd-Alsattar

Engineering and Technology Journal, 2013, Volume 31, Issue 21, Pages 478-488

This paper presents a status report on evaluation of the asphalt pavement using the ground penetration radar device (GPR) in one of the University of Technology streets about 92 m length. The technique of GPR is a nondestructive geophysical method that gives information about the thickness of asphalt pavement layers, existence of drainage pipes, rutting places and produces a continuous cross-sectional profile or record of subsurface features without drilling, probing, or digging.
Three samples of asphalt were taken from different places of the street. The thickness of asphalt layers were measured from these samples. One of the samples consists of two layers and the others of one layer.
Comparison of the two results of the thickness from the device and the sample indicate that there was very slight difference between them.

Assessment the Impact of Different Hydrated Lime Addition Methods on Fatigue Life Characteristic

Amjad H. K. Albayati; Ahmed M. Mohammed

Engineering and Technology Journal, 2013, Volume 31, Issue 21, Pages 489-511

The purpose of this study is to evaluate the effect of hydrated lime addition methods as filler replacement on fatigue performance of Hot Mix Asphalt (HMA). Three types of addition methods of hydrated lime were introduced namely dry HL on dry aggregate and saturated surface aggregate above 3% and slurry HL on dry aggregate, ordinary Lime stone powder was reduced by three HL percentage (1.0, 2.0 and 3.0 %). The effect of different methods were investigated on the fatigue properties of HMA using, third-point flexural fatigue bending Test. Pneumatic Repeated Load System (PRLS) was carried out to establish the effect of hydrated lime on the fatigue failure criteria and to select the proper hydrated lime application methods on fatigue behavior of HMA mixtures. The fatigue functions for asphalt mixture with hydrated lime are obtained and compared, and it confirm that the fatigue property of asphalt mixture can be improved using all methods and the addition methods were exhibited different optimality for the result due to its effect . The test results were carried out through the performance analysis using Vesys 5W (2003) to study the long term effectiveness of hydrated lime effect.

Investigation of Factors Affecting Recovery Priority of Roads Damaged by Natural Disasters/Armed Conflicts

Rasha Hassan Al-Rubaee

Engineering and Technology Journal, 2013, Volume 31, Issue 21, Pages 512-536

Natural disasters/armed conflicts can cause major damage to road networks of the affected area. This can lead to significant impact not only on the road networks. The major challenge in the aftermath of such events is to ensure a speedy recovery/rehabilitation of roads and transportation networks so that regeneration can commence in an effective manner. Prioritizing regeneration of the road network may need context of a range of requirements including health, education, security, and economic amongst many that will also require addressing. This study has been conducted to give a better understanding of major factors that govern road recovery prioritization across the affected region in Iraq. These factors need to be used in an effective and efficient manner that can help in determining the road recovery priority.
Interviews and a questionnaire survey are conducted with experts in road reconstruction and maintenance organisations to investigate the impact of the important proposed affecting factors that can be critical for determining the recovery priority of damaged roads. Five estimated groups of factors have been included in this study, which are: socio-economic, road network, traffic, damage and financial factors. Each group also consists of a number of estimated sub-group factors. As a result, twenty nine factors have been chosen in this study.
It has been found from the results of the interviews and questionnaire that the proposed factors and factor groups are with a level of importance of high and very high. This indicates that the groups and factors included in this study are important for the successful building and implementation of the process and procedures of the road recovery priority in the road rehabilitation projects.
Each estimated factor within each proposed group used in this study contributes a different weight value to the overall road recovery priority. According to the questionnaire’s results, the most important factors are: number of critical socio-economic facilities, type of road, delay time, severity of damage and effect on the economic. Moreover, a different weight has been contributed by each estimated group. Based on the questionnaire results, it was found that the major contribution is from the financial factor group.

A Finite Element Model for Rutting Prediction of Flexible Pavement Considering Temperature Effect

Mohammed Salih Abd-Ali

Engineering and Technology Journal, 2013, Volume 31, Issue 21, Pages 537-548

Permanent deformation in asphalt layers which manifestation on pavement surface is named rutting which represents one of the most significant distress of asphalt pavements. Different empirical models have been used to calculate permanent deformations which include traffic conditions and temperature effect. These empirical models were calibrated in a three dimensional finite element commercial software package. Finite element analysis through ANSYS computer software (version 11.0) was used to analyze three dimensional pavement structures and in order to investigate the impact of wheel load on rutting formation and pavement response considering temperature effect. In that model, the asphalt layer was assumed to follow a viscoelastic behavior by depending on dynamic modulus using Timm and Newcomb model. While, granular and subgrade layers were presented as linear-elastic perfectly plastic based on Drucker-Prager model. After insuring the model validation, the study investigated the effect of temperature on the rutting depth and plastic strain as a pavement response. The analysis of results showed that the rut depth and plastic strain increases with increasing the temperature.

Using Recycled Construction Rubbles to Improve the Properties of Subbase

Shakir A. AL-Mashhadani; Shatha Sadiq

Engineering and Technology Journal, 2013, Volume 31, Issue 21, Pages 549-564

Demolished concrete structures proven to be a good source of construction materials. This paper studies the utility of using recycled construction rubbles to improve some properties of compacted subbase .Different subbase materials were produced with 0%, 25%, 50%, 75% of recycled construction rubbles aggregate as a partial replacement of natural subbase. The standard tests were conducted on the choosed maerials before and after the replacement. It is found from the test results that the recycled construction rubbles can be used significantly to improve the properties of some types of subbase. The CBR values of the subbase materials prepared with crushed concrete, recycled bricks, and ceramic rubbles as a partial replacement were better than those of natural subbase materials. The performance of subbase containing crushed concrete rubbles was better than the performance of subbase containing crushed clay bricks and ceramics. The CBR values for all subbases were greater than 45%, which is accepted as per the requirements CRB specifications in Iraq.

Modeling Stability and Flow of Asphalt Mixes Using Optimum Asphalt content

Hasan H. Al-Baidhani; Maan S. Hassan

Engineering and Technology Journal, 2013, Volume 31, Issue 21, Pages 465-577

The main aim of this study was to evaluate the asphalt mixture properties for samples that were taken from different sites and plants: Amanat Baghdad, Faluja municipality, and Baghdad Governorate, which almost produced in private plants. Forty seven asphalt mixtures samples were tested following Marshall Test. The tested properties were: Marshall Stability, Marshall Flow, specimen density, and air voids. Asphalt extraction was carried out according to quantative extraction of bitumen from paving mixtures test.
A statistical analysis of the collected field data was performed and a prediction model was built. The variables such as asphalt content, stability and flow data were analyzed using computer software. The statistical analysis includes four stages: data extraction and evaluation, verification, calibration, and validation.
Results of this study indicate that both of Marshall Stability and Marshall Flow correlate positively with asphalt content, but with different degree. Asphalt content affect Stability property much more than flow property of the asphalt mixes.

The impact of Dust and Sand Storms on Traffic Safety of Tikrit City in Particular and Iraq in General

Nabeal Ibraheim Hussein

Engineering and Technology Journal, 2013, Volume 31, Issue 21, Pages 11-27

The aims are to study the effect of dust storms and sand on traffic safety in Iraq in general and in Salahuddin province in particular, especially as the dust storms have become a threat to road users (people and vehicles) and result in direct impacts and multiple life and human health and the conditions of social and psychological generally through its impact on the surrounding environment and the traffic of vehicles. Types of dust storms sweeping the region and examined models of them to find out what the quality and measure wind speed caused by the use of statements meteorological previous years has been studied and the work of a questionnaire distributed to drivers of vehicles to demonstrate the impact of these storms on them and the work program of statistical analysis, the results showed that storms pose a threat heavily on traffic safety, but local storms more dangerous than storms overall public because they suddenly appear and disappear in less than an hour and there are no signs or warning to occur and surprised the driver or pedestrian and cause confusion and traffic accidents. Recommendations of which was given the green belts around cities, landscaping and paving roads and sidewalks non-tiled and install some desert areas either salt or sprinkled with other suitable materials.

Evaluating and Improving the Efficiency of Intersection of Freeway Off-Ramps with Arterial Roadway

Atheer N. Hameed

Engineering and Technology Journal, 2013, Volume 31, Issue 21, Pages 28-37

The signalized intersections are considering one of the critical elements in facility work of urban arterial roads. Thus, it is necessary to improve the signalized intersections system not only to increase the ability of flow on the major and minor roads but also to increase the neighboring freeways ability to work with high efficiency.
In the 4-leg signalized intersections, left-turn effect greatly on the capacity, if left-turn movements eliminated by converting it to right and through, so that, the signal can operate with only two phases instead of four phases and capacity will increase. The objective of this study was to evaluate the influence of eliminating left-turn movements (converting it to through and right movements) on the level of service for an intersection of freeway off-ramps with arterial roadway (figure. 1), in order to decrease the congestion on the oversaturated off-ramps, which affect the traffic flow on freeway. Also studying the influence of this elimination and converting on: (1) average system delay, (2) fuel consumption, (3) average travel time, (4) average delay on freeway off-ramps and (5) average queues lengths on freeway. This elimination and converting will be carried out by constructing two roundabouts (nearby to the intersection) on arterial roadway Figures. (5 & 6). Full-movement signalized intersection with two roundabouts were compared before and after elimination left-turn movements through simulation with the use of the Synchro 6 simulation package. The results showed a significant improvement in level of service for the studied intersection. In addition, significant decrease in average delay and average travel time, and minor decrease in fuel consumption. The results also showed a significant decrease in average delay on freeway off-ramps and queues lengths on freeway.

Estimating the Passenger Car Eqaivalent (PCE) for Different Type of Vehicles on the Signalized Intersections

Ahmed Subhi

Engineering and Technology Journal, 2013, Volume 31, Issue 21, Pages 38-49

Drivers in Iraq tend to disregard lane markings and use every available meter of signalized intersections approach width. Thus, actual vehicles queues usually exceed marked lanes. This paper analyzes the effect of this behavior on signalized intersection capacity by estimating the passenger car equivalent (PCE) for different types of vehicles under these prevailing conditions. Multiple linear regression analysis was employed by considering all the through lanes in the approach as the unit of analysis; the necessary data were collected from a congested signalized intersection within Al-Hilla Province by using videotaping and for a period of four days (8 hours per day). The study resulted in some useful findings for signalized intersections capacity analysis. The saturation flow rate was estimated to be 1818 passenger cars per hour of green per marked lane. The results revealed that the minibus (e.g., 25-seat Toyota Coaster) and the passenger car time headways were equal, and thus have the same effect on intersection capacity. It is believed that this is due to the observed reckless driving of minibus drivers.

Common Defects and Distresses in Flexible Pavements in the Middle part of Iraq and Their Main Reasons

Khawla H. hassan

Engineering and Technology Journal, 2013, Volume 31, Issue 21, Pages 50-62

Operation and maintenance problems of highways network in Iraq are going continuously to worsen in up-keeping and serviceability presented, even although, doubling the effort, appropriation fund, and expenditure amounts on enhancement them, improvement their serviceability, and increase their design age. All the above necessitate searching on the reasons of falling performance levels in the design, construction, operating, and maintenance at the same manner. The main reasons of highways network failure are the fast appearance and increase in intensity of deformation -with absence of periodically maintenance - in the pavement surfaces specially asphaltic pavement or flexible pavement that represent the common and dependable type in construction of that network.
The recent research concern in studying the forms and reasons of asphaltic pavement deformations and definition their common reasons that sharing in appear more than one form of deformations according to Iraqi specification and the worldwide specification that depended in Iraq, in addition to compare them with the deformation recorded in the studying region, which is the middle region in Iraq. The recent research reach to that the increasing of traffic loading in weights and repetition, weakness of Subgrade soil, increasing the volume changing in base course duo to deficiency of proper drainage system, in addition to bad asphaltic mixture design are the main reasons causes appearance the most risky types of deformations in pavement surface, that extended in high percent reach to more than 62% depending on five of urban and rural highway sections in the studying region in overall length about 114km approximately, with listing the differences in their geometric design.