Recently, the exhaustion of new aggregates and the rising price of " raw materials" hav... more Recently, the exhaustion of new aggregates and the rising price of " raw materials" have caused the increasing exploitation of "reclaimed asphalt pavement "(RAP) in pavement construction and rehabilitation. It is being reported that the usage of RAP does not only reduce the cost of pavement construction projects due to the less consumption of asphalt and aggregate but also saves land resources and greatly protects the environment, Where the same materials used in the construction of the original highway system can be reused to rebuild, repair and maintain it. Where appropriate, recycled Aggregates and other highway construction materials make a good economy; in the" environmental and engineering' sense, with supply limited and demand increasing, HMA producers have begun the use of "Reclaimed Asphalt Pavement" (RAP) as a value component of the" HMA." For this reason, there is renewed interest in increasing the amount of RAP used in hot...
During the last two decades, a significant increase in the number of vehicles in Baghdad city rel... more During the last two decades, a significant increase in the number of vehicles in Baghdad city related to uncontrolled axle loading, hot climate summer, lack of asphalt pavement maintenance, and heavy traffic has combined and led to severe consequences in the paved road. Therefore, asphalt cement enhancement and improvement is the first key to solving and correcting these issues. Recently, nanomaterial has gained considerable recognition in asphalt technology as the new modifier due to the homogeneity, dispersion, and large surface area in contact with asphalt particles. This paper investigates the effect of adding nano CaCO3 into asphalt cement. The laboratory experiment included 40-50 penetration grades prepared with different content 1, 3,5, and 7% to quantify the potential benefit of a physical test of Asphalt, Marshall properties, and tensile strength of hot mix asphalt. The testing result indicated that nano-CaCO3 modified asphalt with a 5% improved penetration grade and soften...
A tack coat is a thin cut-back cement or asphalt emulsion coating applied on an existing non-abso... more A tack coat is a thin cut-back cement or asphalt emulsion coating applied on an existing non-absorbent pavement. A good bonding between the asphalt and concrete is necessary to provide sufficient structural strength. Poor adhesion will result in shear failure. The shear test is one of the basic tests to determine bond strength. This study aims to quantify the best shear resistance obtained using three types of cut-back asphalts (RC70, RC800 modified with polymer 4.5% and MC70), PG (76-10) modified asphalt cement with polymer 4.5%, Sikadur®-31 CF usage at elevated temperatures between +25°C and +45°C and Nitomortar TC2000 epoxy from Fosrok company. All are applied on concrete surfaces with an application rate of 0.5kg/m2 except for Nitomortar, which depends on layer thickness ranges between (1-2.5) mm instead of the application rate. A special attachment and loading mechanism were designed to facilitate the measurement of the asphalt-to-concrete contact shear strength in Al-Ahmad Lab...
A tack coat is a minimal coating of asphalt cement, cut-back asphalt, or asphalt emulsion to an e... more A tack coat is a minimal coating of asphalt cement, cut-back asphalt, or asphalt emulsion to an existing pavement surface between layers to guarantee proper bonding between the two layers and longitudinal and transverse Joints. Numerous researchers have assessed interlayer adhesion employing failure-mode behavior tests, such as pull-off, direct shear, and torsion testing. This study aims to quantify the best tensile resistance obtained using PG (76-10) modified asphalt cement with polymer 4.5%, Sikadur®-31 CF (S.E) usage at elevated temperatures between +25 °C and +45 °C, an epoxy-resin-based adhesive, and repair mortar with specific fillers. And Nitomortar TC2000 epoxy (F.E) resin-based sealing compound from Fosrok Company. All are applied on concrete surfaces at a rate of 0.5 kg/m2 except for Nitomortar, which depends on layer thickness ranges between (1-2.5) mm instead of the application rate. The Proceq DYNA Z16 pull–off tester is used to measure the tensile strength at a rate o...
International journal of engineering research and technology, 2016
: This paper studies the behavior of self compacted concrete (SCC) deep beam and the parameters a... more : This paper studies the behavior of self compacted concrete (SCC) deep beam and the parameters affecting the ultimate capacity. Eighteen specimens represented by ANSYS 11 program to study the effect of several variables like the percentage of shear span to effective depth ratio (a/d), areas of the web openings, web openings shape, concrete compressive strength (f'c), horizontal stirrups and vertical stirrups on the ultimate capacity of SCC deep beams. The finite element model uses Solid65 to model the SCC deep beams and link180 to model steel reinforcement. All beams are simply supported and tested under two concentrated point loads. All beams have the same dimensions and reinforcement. They have an overall length of 1200 mm, a height of 440 mm and a width of 110 mm. Conclusions showed that reducing the shear span to effective depth ratio (a/d) from 1.2 to 0.8 leads to an increase in ultimate capacity by 20%. The deep beams ultimate capacity increases by 9% after reducing the s...
The engineering problems of problematic soils are mainly related to their mechanical, physical, a... more The engineering problems of problematic soils are mainly related to their mechanical, physical, and mineralogical properties. Extensive efforts have been directed to mitigate damages that may happen for structures constructed on, or in these soils' types. Both conventional materials (e.g. cement, lime, etc.), chemical and produced materials were blended, mixed, or added to soils to improve their geotechnical properties. In the last years, different additives from the wastes of industrial processes have been adopted in engineering researches to improve soils. This paper reviews different industrial wastes materials (e.g., fly ash, blast slag, rice husk ash) as soil stabilizers, where the use of them has economic and engineering benefits. The effect of these materials on physical properties, compaction characteristics, compressive strength, and bearing ratio of soils have been presented, studied, and discussed. The contents of these materials are widely varied from reference to re...
The loss of natural resources is one of the growing problems due to the inability to replace thes... more The loss of natural resources is one of the growing problems due to the inability to replace these resources on the one hand, and environmental pollution resulting from damage to asphalt pavements on the other hand. So the use of RAP in asphalt mixture has been promoted. The research addressed the inclusion of RAP in bulk and its effect on the resistance of asphalt mixtures to "RUTTING" as one of the most important problems. What mixtures are exposed to during high-temperature cycles where there are four different percentages of RAP (10, 15, 20, 25%), (30, 40, 50, 60%) and (40, 50, 60, 70%) For each of the three paving layers (surface, bond, base) respectively. Four samples were taken at three different temperatures (45, 55, and 70) degrees Celsius of asphalt mixtures for each of the three pavement layers. Various types of asphalt bonds have been used. To evaluate mixtures during the Hamburg Wheel Track test at different temperatures. The results indicated an improvement i...
The objective of this paper is find the effect of using iron oxide as a filler on the Marshall st... more The objective of this paper is find the effect of using iron oxide as a filler on the Marshall stability, flow and the volumetric properties of HMA and compared the results with conventional HMA using limestone dust. Three blends were used: coarse, mid and fine with neat bitumen (AC 40-50). One aggregate type (crushed) with two types of fillers: limestone and iron oxide III (α- ) with three different filler content 6%, 8% and 10%. The Marshall mix design was conducted on the three blends and the optimum binder content is computed for each blend. The Marshall stability test results and the volumetric properties analysis showed that increasing the iron oxide content from 6% to 10% increases the stability about 28%, 17% , 16% for the coarse , mid and fine mixtures respectively. This increment in stability of mixtures using iron oxide related to the increment in specific gravity of the mix (Gmb) by (1.3% to 1.5% about 30 to 50 kg/m3). On the other hand, the flow of mixtures is decrease...
Rutting is considered as the most generated distress in Iraqi roads as a result of the high tempe... more Rutting is considered as the most generated distress in Iraqi roads as a result of the high temperature and excessive traffic load. So, it is essential to utilize polymer modified binder to increase the performance of pavements. The objective of this paper is to assess the effect of aggregate gradation and filler content on the rutting formation of Colored Hot Mix Asphalt CHMA. The HMA was colored by using iron oxide as filler to produce red HMA. Two blends were used: fine and coarse with two different types of filler iron oxide for CHMA and limestone for conventional HMA with two filler content 6% and 10%. Neat (AC 40-50) and modified asphalt (AC 40-50 + 4%SBS) were used. Tests are held on adding 4% Styrene Butadiene Styrene )SBS( by the weight of neat asphalt (AC 40-50) to raise the performance grade by two grades from PG (64-16) to PG (76-16) [1] and [2]. The wheel tracking test is used to assess the rut depth of the CHMA. The test results showed that the using iron oxide with ne...
Field compaction equipment used for fine grained soil usually applies a kneading action or vibrat... more Field compaction equipment used for fine grained soil usually applies a kneading action or vibration that produces shear forces which also reshape soil particles arrangement. A state that might not be completely simulated by laboratory Proctor tests. This study aims at investigating the significance of using the newer modified Texas superpave gyratory compactor (SGC) to simulate field compaction of fine grained soil due to itsability to apply loads in different anglesgenerating shear forces on the compacted soilspecimens. Two types of soil (A-4) and (A-7-6)were compacted using standard Proctor,modified Proctor and (SGC). The results werecompared to dry field densities of the same soilin order to evaluate the most representative test.It was found that maximum dry densities of soiltype (A-4) obtained using (SGC) under (200kPa) and (600 kPa) were lower by (2.07%) andhigher by (1.35%) than the maximum drydensities obtained using standard and modifiedProctor tests respectively. It was al...
Many researches used dissipated energy approach to find the changing of the asphalt binder proper... more Many researches used dissipated energy approach to find the changing of the asphalt binder properties through repeated cyclic loading with accumulation of damage. In this research time-sweep and stress sweep tests were used to simulate fatigue phenomenon for the different production refineries of Iraqi asphalt binders (Nasiriya, Daurah and Basrah) by applying repeated cyclic load of strain or stress at chosen loading frequency and temperatures. The asphalt binders were aged by rolling thin film oven for simulating influence of oxidation in the mixing and compaction of HMA, and pressure aging vessel to represent long term oxidation life. All the tests were conducted at 10 Hz at intermediate temperatures and 3 percent of strain that closest to the HMA mixture beam fatigue behavior [1], different mathematical models were founded to represent relation of the dissipated energy ratio and fatigue life at constant stress value (150 and 200) kPa for RTFO aging and 300, 350 kPa for PAV aging....
Accepted: 14th Aug. 2020 Abstract Most of the soils suffered from significant geotechnical proble... more Accepted: 14th Aug. 2020 Abstract Most of the soils suffered from significant geotechnical problems dependent on factors like the type of soil, soil composition and mineralogy. Especially, the problems related to mechanical and physical properties of soils. Several studies have been used to mitigate the adverse effects of soils through using either additive conventional materials such as cement, lime or these soils blending with produced material and chemical materials. Recently, additives from industrial, agricultural, domestic, and mineral wastes have been used to improve soils. According to literatures, such wastes have been classified as sustainable materials. This paper focuses on stabilizing or improving different soils using sustainable materials. These materials provided engineering and economic benefits through improving the geotechnical properties of soil. According to the results of this review, the effect of different sustainable materials on compaction characteristics, ...
A polymer modification is used to improve th e fundamental properties of asphalt binders as those... more A polymer modification is used to improve th e fundamental properties of asphalt binders as those properties relate to the p erformance of asphalt mixtures. Adhesion and cohesion are two important related properties of asphalt binders that can affect asphalt mixture performance. The first t arget of this study is to quantify the effects of polymers on the adhesion and cohesio n of the binders. Two types of stones are used in this study, limestone and sandst one. The pneumatic adhesion tensile tester (PATTI) is used to measure the pull- off tensile strength in Wisconsin University, it is found that the tensile strength b etween limestone and styrene butadiene styrene (SBS) polymer increase 26% to 55% as using 2% and 4% of SBS respectively, while increase 54% to 76% when use 2% and 3.5% of Functionalized Polyethylene (PE) polymer respectively. For sandstone, 2% and 4% of SBS causes increasing the strength 5% and 18% respectively, while these values becomes 29% and 51% for asphalt bind...
Rutting is one of the major distresses in pavement. The objective of this paper is to develop an ... more Rutting is one of the major distresses in pavement. The objective of this paper is to develop an improved asphalt binder grading system for Iraq based on the principal of Superpave system, and increasing performance grade of product asphalt binder in Iraq using polymers without raising the viscosity of the binder. Two types of polymers are used, Plastomers, Functionalized Polyethylene (PE) which is developed by asphalt research group in Wisconsin University in the USA, and Elastomers, Styrene Butadiene Styrene (SBS) with and without cross linker. Mastercurve are drown for these modified binders, Rolling thin film aged, to show effects on rheological properties at high temperature for complex modulus (G*) and phase angle (δ). It concluded that 3.5% of Functionalized Polyethylene polymer (PE) is more effective than 4% of Styrene Butadiene Styrene (SBS) to shift up performance grade of local asphalt binder two grades to be PG (76-16). Furthermore, the viscosity of binders increasing ab...
Since asphalt binder is the most important factor that affects low-temperature cracking. It is im... more 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 lowtemperature 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 bin...
IOP Conference Series: Materials Science and Engineering
This study elucidate a test methodology to execute the creep tests to assess the performance of t... more This study elucidate a test methodology to execute the creep tests to assess the performance of the hot asphalt mixture (HMA) beams by utilizing the bending beam rheometer (BBR) and explain the most issues related to performing this test. Firstly, a comprehensive samples preparation technique has illustrated and the experimental data were presented to evaluate the reliability of this technique. To perform this test, one aggregate gradation and two types of polymer modifiers with three percent of modification for each type of polymers were used. However, experimental results showed that decreasing the testing temperature by an increment of 10 oC can reduce the deflection by 95.6, and 99.13%. Decreasing the temperature from 25 to 15 and 10 oC can increase the creep stiffness by 12.6 and 36.6 time. Which indicate that temperature was a predominant factor affecting the most responses of the hot asphalt Mixtures. besides polymer modification significant effect on the stiffness which is c...
IOP Conference Series: Materials Science and Engineering
In traditional road construction, the most common source materials for roadbed layers are the bor... more In traditional road construction, the most common source materials for roadbed layers are the borrow pits. During the construction process, the source’s materials, excavation, loading, and handling have been considered significant factors on total construction cost. Improving the geotechnical properties of the locally available source materials using the waste materials of the local industry (as additives) is helped in avoiding undesirable additional costs in the field construction. The present paper explains the results of an experimental study of compaction characteristics for subgrade material of districts of Baghdad, Iraq with two different types of local byproduct materials “cement dust and fly ash materials,”. The selected soil, cement dust, and fly ash mixtures were made ready for use in the laboratory, and the mixtures’ compaction properties were investigated. Both light and heavy manual compaction tests were carried out and compared. The effect of selected stabilizers on th...
This paper focused on evaluating the effect of aggregate gradation and polymer modification on in... more This paper focused on evaluating the effect of aggregate gradation and polymer modification on indirect tensile strength (ITS) and the static stiffness for hot asphalt mixtures. In particular, data from ITS tests have been processed to obtain stiffness measurements through the application of Hondros theory. The results showed that fine mixtures had a better tensile strength by 26.3% than the coarse mixtures. The effect of compaction also was examined, the results showed that samples compacted with the Superpave gyratory compactor (SGC) had an enhancement in ITS by 36.58 and 23.1% in comparison with Marshall and roller compactor respectively. Polymer modifiers were used to estimate their effect on tensile strength, adding 4, 6, and 8% of Styrene-Butadiene-Styrene (SBS), which can rise the ITS by 3.2,6.14 and 13.3% of the non-modified asphalt mixture. Furthermore, using 4, 6, and 8 percent of SBS could increase static stiffness by 53.9, 209.6, and 302.4% respectively for roller compac...
Recently, the exhaustion of new aggregates and the rising price of " raw materials" hav... more Recently, the exhaustion of new aggregates and the rising price of " raw materials" have caused the increasing exploitation of "reclaimed asphalt pavement "(RAP) in pavement construction and rehabilitation. It is being reported that the usage of RAP does not only reduce the cost of pavement construction projects due to the less consumption of asphalt and aggregate but also saves land resources and greatly protects the environment, Where the same materials used in the construction of the original highway system can be reused to rebuild, repair and maintain it. Where appropriate, recycled Aggregates and other highway construction materials make a good economy; in the" environmental and engineering' sense, with supply limited and demand increasing, HMA producers have begun the use of "Reclaimed Asphalt Pavement" (RAP) as a value component of the" HMA." For this reason, there is renewed interest in increasing the amount of RAP used in hot...
During the last two decades, a significant increase in the number of vehicles in Baghdad city rel... more During the last two decades, a significant increase in the number of vehicles in Baghdad city related to uncontrolled axle loading, hot climate summer, lack of asphalt pavement maintenance, and heavy traffic has combined and led to severe consequences in the paved road. Therefore, asphalt cement enhancement and improvement is the first key to solving and correcting these issues. Recently, nanomaterial has gained considerable recognition in asphalt technology as the new modifier due to the homogeneity, dispersion, and large surface area in contact with asphalt particles. This paper investigates the effect of adding nano CaCO3 into asphalt cement. The laboratory experiment included 40-50 penetration grades prepared with different content 1, 3,5, and 7% to quantify the potential benefit of a physical test of Asphalt, Marshall properties, and tensile strength of hot mix asphalt. The testing result indicated that nano-CaCO3 modified asphalt with a 5% improved penetration grade and soften...
A tack coat is a thin cut-back cement or asphalt emulsion coating applied on an existing non-abso... more A tack coat is a thin cut-back cement or asphalt emulsion coating applied on an existing non-absorbent pavement. A good bonding between the asphalt and concrete is necessary to provide sufficient structural strength. Poor adhesion will result in shear failure. The shear test is one of the basic tests to determine bond strength. This study aims to quantify the best shear resistance obtained using three types of cut-back asphalts (RC70, RC800 modified with polymer 4.5% and MC70), PG (76-10) modified asphalt cement with polymer 4.5%, Sikadur®-31 CF usage at elevated temperatures between +25°C and +45°C and Nitomortar TC2000 epoxy from Fosrok company. All are applied on concrete surfaces with an application rate of 0.5kg/m2 except for Nitomortar, which depends on layer thickness ranges between (1-2.5) mm instead of the application rate. A special attachment and loading mechanism were designed to facilitate the measurement of the asphalt-to-concrete contact shear strength in Al-Ahmad Lab...
A tack coat is a minimal coating of asphalt cement, cut-back asphalt, or asphalt emulsion to an e... more A tack coat is a minimal coating of asphalt cement, cut-back asphalt, or asphalt emulsion to an existing pavement surface between layers to guarantee proper bonding between the two layers and longitudinal and transverse Joints. Numerous researchers have assessed interlayer adhesion employing failure-mode behavior tests, such as pull-off, direct shear, and torsion testing. This study aims to quantify the best tensile resistance obtained using PG (76-10) modified asphalt cement with polymer 4.5%, Sikadur®-31 CF (S.E) usage at elevated temperatures between +25 °C and +45 °C, an epoxy-resin-based adhesive, and repair mortar with specific fillers. And Nitomortar TC2000 epoxy (F.E) resin-based sealing compound from Fosrok Company. All are applied on concrete surfaces at a rate of 0.5 kg/m2 except for Nitomortar, which depends on layer thickness ranges between (1-2.5) mm instead of the application rate. The Proceq DYNA Z16 pull–off tester is used to measure the tensile strength at a rate o...
International journal of engineering research and technology, 2016
: This paper studies the behavior of self compacted concrete (SCC) deep beam and the parameters a... more : This paper studies the behavior of self compacted concrete (SCC) deep beam and the parameters affecting the ultimate capacity. Eighteen specimens represented by ANSYS 11 program to study the effect of several variables like the percentage of shear span to effective depth ratio (a/d), areas of the web openings, web openings shape, concrete compressive strength (f'c), horizontal stirrups and vertical stirrups on the ultimate capacity of SCC deep beams. The finite element model uses Solid65 to model the SCC deep beams and link180 to model steel reinforcement. All beams are simply supported and tested under two concentrated point loads. All beams have the same dimensions and reinforcement. They have an overall length of 1200 mm, a height of 440 mm and a width of 110 mm. Conclusions showed that reducing the shear span to effective depth ratio (a/d) from 1.2 to 0.8 leads to an increase in ultimate capacity by 20%. The deep beams ultimate capacity increases by 9% after reducing the s...
The engineering problems of problematic soils are mainly related to their mechanical, physical, a... more The engineering problems of problematic soils are mainly related to their mechanical, physical, and mineralogical properties. Extensive efforts have been directed to mitigate damages that may happen for structures constructed on, or in these soils' types. Both conventional materials (e.g. cement, lime, etc.), chemical and produced materials were blended, mixed, or added to soils to improve their geotechnical properties. In the last years, different additives from the wastes of industrial processes have been adopted in engineering researches to improve soils. This paper reviews different industrial wastes materials (e.g., fly ash, blast slag, rice husk ash) as soil stabilizers, where the use of them has economic and engineering benefits. The effect of these materials on physical properties, compaction characteristics, compressive strength, and bearing ratio of soils have been presented, studied, and discussed. The contents of these materials are widely varied from reference to re...
The loss of natural resources is one of the growing problems due to the inability to replace thes... more The loss of natural resources is one of the growing problems due to the inability to replace these resources on the one hand, and environmental pollution resulting from damage to asphalt pavements on the other hand. So the use of RAP in asphalt mixture has been promoted. The research addressed the inclusion of RAP in bulk and its effect on the resistance of asphalt mixtures to "RUTTING" as one of the most important problems. What mixtures are exposed to during high-temperature cycles where there are four different percentages of RAP (10, 15, 20, 25%), (30, 40, 50, 60%) and (40, 50, 60, 70%) For each of the three paving layers (surface, bond, base) respectively. Four samples were taken at three different temperatures (45, 55, and 70) degrees Celsius of asphalt mixtures for each of the three pavement layers. Various types of asphalt bonds have been used. To evaluate mixtures during the Hamburg Wheel Track test at different temperatures. The results indicated an improvement i...
The objective of this paper is find the effect of using iron oxide as a filler on the Marshall st... more The objective of this paper is find the effect of using iron oxide as a filler on the Marshall stability, flow and the volumetric properties of HMA and compared the results with conventional HMA using limestone dust. Three blends were used: coarse, mid and fine with neat bitumen (AC 40-50). One aggregate type (crushed) with two types of fillers: limestone and iron oxide III (α- ) with three different filler content 6%, 8% and 10%. The Marshall mix design was conducted on the three blends and the optimum binder content is computed for each blend. The Marshall stability test results and the volumetric properties analysis showed that increasing the iron oxide content from 6% to 10% increases the stability about 28%, 17% , 16% for the coarse , mid and fine mixtures respectively. This increment in stability of mixtures using iron oxide related to the increment in specific gravity of the mix (Gmb) by (1.3% to 1.5% about 30 to 50 kg/m3). On the other hand, the flow of mixtures is decrease...
Rutting is considered as the most generated distress in Iraqi roads as a result of the high tempe... more Rutting is considered as the most generated distress in Iraqi roads as a result of the high temperature and excessive traffic load. So, it is essential to utilize polymer modified binder to increase the performance of pavements. The objective of this paper is to assess the effect of aggregate gradation and filler content on the rutting formation of Colored Hot Mix Asphalt CHMA. The HMA was colored by using iron oxide as filler to produce red HMA. Two blends were used: fine and coarse with two different types of filler iron oxide for CHMA and limestone for conventional HMA with two filler content 6% and 10%. Neat (AC 40-50) and modified asphalt (AC 40-50 + 4%SBS) were used. Tests are held on adding 4% Styrene Butadiene Styrene )SBS( by the weight of neat asphalt (AC 40-50) to raise the performance grade by two grades from PG (64-16) to PG (76-16) [1] and [2]. The wheel tracking test is used to assess the rut depth of the CHMA. The test results showed that the using iron oxide with ne...
Field compaction equipment used for fine grained soil usually applies a kneading action or vibrat... more Field compaction equipment used for fine grained soil usually applies a kneading action or vibration that produces shear forces which also reshape soil particles arrangement. A state that might not be completely simulated by laboratory Proctor tests. This study aims at investigating the significance of using the newer modified Texas superpave gyratory compactor (SGC) to simulate field compaction of fine grained soil due to itsability to apply loads in different anglesgenerating shear forces on the compacted soilspecimens. Two types of soil (A-4) and (A-7-6)were compacted using standard Proctor,modified Proctor and (SGC). The results werecompared to dry field densities of the same soilin order to evaluate the most representative test.It was found that maximum dry densities of soiltype (A-4) obtained using (SGC) under (200kPa) and (600 kPa) were lower by (2.07%) andhigher by (1.35%) than the maximum drydensities obtained using standard and modifiedProctor tests respectively. It was al...
Many researches used dissipated energy approach to find the changing of the asphalt binder proper... more Many researches used dissipated energy approach to find the changing of the asphalt binder properties through repeated cyclic loading with accumulation of damage. In this research time-sweep and stress sweep tests were used to simulate fatigue phenomenon for the different production refineries of Iraqi asphalt binders (Nasiriya, Daurah and Basrah) by applying repeated cyclic load of strain or stress at chosen loading frequency and temperatures. The asphalt binders were aged by rolling thin film oven for simulating influence of oxidation in the mixing and compaction of HMA, and pressure aging vessel to represent long term oxidation life. All the tests were conducted at 10 Hz at intermediate temperatures and 3 percent of strain that closest to the HMA mixture beam fatigue behavior [1], different mathematical models were founded to represent relation of the dissipated energy ratio and fatigue life at constant stress value (150 and 200) kPa for RTFO aging and 300, 350 kPa for PAV aging....
Accepted: 14th Aug. 2020 Abstract Most of the soils suffered from significant geotechnical proble... more Accepted: 14th Aug. 2020 Abstract Most of the soils suffered from significant geotechnical problems dependent on factors like the type of soil, soil composition and mineralogy. Especially, the problems related to mechanical and physical properties of soils. Several studies have been used to mitigate the adverse effects of soils through using either additive conventional materials such as cement, lime or these soils blending with produced material and chemical materials. Recently, additives from industrial, agricultural, domestic, and mineral wastes have been used to improve soils. According to literatures, such wastes have been classified as sustainable materials. This paper focuses on stabilizing or improving different soils using sustainable materials. These materials provided engineering and economic benefits through improving the geotechnical properties of soil. According to the results of this review, the effect of different sustainable materials on compaction characteristics, ...
A polymer modification is used to improve th e fundamental properties of asphalt binders as those... more A polymer modification is used to improve th e fundamental properties of asphalt binders as those properties relate to the p erformance of asphalt mixtures. Adhesion and cohesion are two important related properties of asphalt binders that can affect asphalt mixture performance. The first t arget of this study is to quantify the effects of polymers on the adhesion and cohesio n of the binders. Two types of stones are used in this study, limestone and sandst one. The pneumatic adhesion tensile tester (PATTI) is used to measure the pull- off tensile strength in Wisconsin University, it is found that the tensile strength b etween limestone and styrene butadiene styrene (SBS) polymer increase 26% to 55% as using 2% and 4% of SBS respectively, while increase 54% to 76% when use 2% and 3.5% of Functionalized Polyethylene (PE) polymer respectively. For sandstone, 2% and 4% of SBS causes increasing the strength 5% and 18% respectively, while these values becomes 29% and 51% for asphalt bind...
Rutting is one of the major distresses in pavement. The objective of this paper is to develop an ... more Rutting is one of the major distresses in pavement. The objective of this paper is to develop an improved asphalt binder grading system for Iraq based on the principal of Superpave system, and increasing performance grade of product asphalt binder in Iraq using polymers without raising the viscosity of the binder. Two types of polymers are used, Plastomers, Functionalized Polyethylene (PE) which is developed by asphalt research group in Wisconsin University in the USA, and Elastomers, Styrene Butadiene Styrene (SBS) with and without cross linker. Mastercurve are drown for these modified binders, Rolling thin film aged, to show effects on rheological properties at high temperature for complex modulus (G*) and phase angle (δ). It concluded that 3.5% of Functionalized Polyethylene polymer (PE) is more effective than 4% of Styrene Butadiene Styrene (SBS) to shift up performance grade of local asphalt binder two grades to be PG (76-16). Furthermore, the viscosity of binders increasing ab...
Since asphalt binder is the most important factor that affects low-temperature cracking. It is im... more 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 lowtemperature 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 bin...
IOP Conference Series: Materials Science and Engineering
This study elucidate a test methodology to execute the creep tests to assess the performance of t... more This study elucidate a test methodology to execute the creep tests to assess the performance of the hot asphalt mixture (HMA) beams by utilizing the bending beam rheometer (BBR) and explain the most issues related to performing this test. Firstly, a comprehensive samples preparation technique has illustrated and the experimental data were presented to evaluate the reliability of this technique. To perform this test, one aggregate gradation and two types of polymer modifiers with three percent of modification for each type of polymers were used. However, experimental results showed that decreasing the testing temperature by an increment of 10 oC can reduce the deflection by 95.6, and 99.13%. Decreasing the temperature from 25 to 15 and 10 oC can increase the creep stiffness by 12.6 and 36.6 time. Which indicate that temperature was a predominant factor affecting the most responses of the hot asphalt Mixtures. besides polymer modification significant effect on the stiffness which is c...
IOP Conference Series: Materials Science and Engineering
In traditional road construction, the most common source materials for roadbed layers are the bor... more In traditional road construction, the most common source materials for roadbed layers are the borrow pits. During the construction process, the source’s materials, excavation, loading, and handling have been considered significant factors on total construction cost. Improving the geotechnical properties of the locally available source materials using the waste materials of the local industry (as additives) is helped in avoiding undesirable additional costs in the field construction. The present paper explains the results of an experimental study of compaction characteristics for subgrade material of districts of Baghdad, Iraq with two different types of local byproduct materials “cement dust and fly ash materials,”. The selected soil, cement dust, and fly ash mixtures were made ready for use in the laboratory, and the mixtures’ compaction properties were investigated. Both light and heavy manual compaction tests were carried out and compared. The effect of selected stabilizers on th...
This paper focused on evaluating the effect of aggregate gradation and polymer modification on in... more This paper focused on evaluating the effect of aggregate gradation and polymer modification on indirect tensile strength (ITS) and the static stiffness for hot asphalt mixtures. In particular, data from ITS tests have been processed to obtain stiffness measurements through the application of Hondros theory. The results showed that fine mixtures had a better tensile strength by 26.3% than the coarse mixtures. The effect of compaction also was examined, the results showed that samples compacted with the Superpave gyratory compactor (SGC) had an enhancement in ITS by 36.58 and 23.1% in comparison with Marshall and roller compactor respectively. Polymer modifiers were used to estimate their effect on tensile strength, adding 4, 6, and 8% of Styrene-Butadiene-Styrene (SBS), which can rise the ITS by 3.2,6.14 and 13.3% of the non-modified asphalt mixture. Furthermore, using 4, 6, and 8 percent of SBS could increase static stiffness by 53.9, 209.6, and 302.4% respectively for roller compac...
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Papers by alaa abed