Abstract: Airport runways and taxiways are commonly comprised of a flexible pavement with an asphalt surface. Marshall-designed asphalt with sawn grooves is the most frequent airport asphalt surface material. However, some airports have adopted alternate asphalt mixtures for improved resistance to shear stress and for increased surface texture, allowing grooving to be avoided. Of the alternate asphalt mixtures, stone mastic asphalt is the most commonly reported. Resistance to shear stress is a critical performance requirement for airport surface asphalt. Shear stress resistance minimises the risk of rutting, shoving and groove closure. However, fracture resistance must not be ignored when developing even more shear resistance asphalt mixtures. Significant distress in airport asphalt surfaces, compliant with the traditional prescriptive specification, has increased interest in a performance-based airport asphalt specification. Commonly reported distresses include groove closure in slow moving aircraft areas and shearing in heavy aircraft braking zones. Development of reliable performance-indicative test methods is expected in the future and will enable warranted performance-based asphalt mixture design for airport surfaces.

Abstract: This study was carried using finite element software (Plaxis) in studying the Engineering behavior of erodible soil-quarry dust composite at a proportion of 50% quarry dust and 10% cement. It discusses the effects of decorative street light through numerical analysis using the Finite Elements Method. Plaxis program v8.2 was applied to model the soil behavior. The Mohr-Coulomb model reveals that the deformations are concentrated exclusively on the base course, with the appearance of plastic tension cut-off points on base course. The structure was subjected to double point loads of 50 kN/m each which resulted to 100 kN/m. The results shows that the pavement deformed at load 85.16kN/m which showed that the soil strength cannot withhold the pressure from the street light. The load displacement acting on the base of the highway in study is . The result also shows that failure was concentrated at the base course of the pavement. This was due to the presence of underground water beneath the phreatic level. The quarry dust is a good replacement to weak soil or a good additive to help improved a problematic soil. From analysis, the soil strength lies below the effective stress acting on the pavement which is equal to 85.16 kN/m. It is advisable to replace some quantities of the existing soil and be replaced by quarry dust since quarry dust is a waste product from crushing of stones. Lastly, about 30% of the existing soil should be replaced by either the mixture of lateritic soil and quarry dust or the soil there should be used as subbase which may not be economical.

Abstract: With the increased knowledge of sustainable pavement construction, recycled materials more and more are being used in roadwork applications, especially as base materials. Among various recycled materials, recycled glass aggregate is of the special attraction in the present study. The main goal of this investigation is evaluating the behavior of base course containing recycled glass using resilient modulus (Mr) from laboratory testing. In this regard, recycled glass (RG) is replaced the same range size of the local base course material (MG20) based on volumetric method. The studied RG aggregate was in the range size of 0–5 mm. The results revealed that as RG content increased, Mr values of blends decreased. Furthermore, the shear strength of blends followed the similar trend as it decreases by RG contents. Finally, based on the experimental observation a model was proposed to interpret the effects of RG on the resilient modulus values of blends. Conclusively, using RG up to 25% of MG20 may change the growing trend of environmental problems, in a green way, without significant effects on the mechanical behavior.

Abstract: Asphalt pavement is known to be deteriorated by the repetitive traffic loading, climatic condition, aging of asphalt mixture etc. after opening to traffic. Crack plays a critical role in pavement deterioration. Several studies have been conducted to obtain a better understanding with respect to climate related pavement fracture behavior. However, the limitation of the previous researches was that most of them were conducted by laboratory experiment or numerical simulation. The main objective of this study is to determine the relationship between the continuously changed temperature and the relative crack opening in asphalt base course by analyzing the data collected from an in-service asphalt pavement. To achieve this objective, four artificial transverse cracks were first induced on the asphalt subbase of a test track, and then their temperatures and crack opening were recorded by monitoring systems. Diurnal and annual trends of temperature and relative crack opening as well as their relationship were investigated and discussed. In this study, a test track with defined asphalt layers was constructed, which was specially equipped with sensors that continuously monitored the temperatures and opening widths of structural cracks in the test track. On the basis of the findings obtained, it is possible for the first time to make direct statements about the deformation conditions occurring in an asphalt base layer as a result of temperature.

Abstract: Oil shale semicoke is a hazardous byproduct in oil shale retorting process. In Jilin province, China, abundant oil shale resources are mainly used for retorting shale oil accompanying with a large number of oil shale semicoke slags, which will generally cause environmental pollution and disposal problems. If oil shale semicoke can be utilized as a road base or subbase course construction material, it will be a great help to the disposal of a long-term accumulated oil shale semicoke in landfill sites. Moreover, the resource treatment of oil shale semicoke in road project construction could obtain positive social and economic benefits. Subsequently, we conducted a series of laboratory tests to study the practicability of cement-stabilized oil shale semicoke as a road base or subbase course construction material, including the raw material test, modified compaction test, unconfined compressive strength (UCS) test, splitting tensile strength (STS) test, compressive resilient modulus (CRM) test, and freezing-thawing test. In this paper, test results were compared with the technical requirements of Chinese road base construction specification, preliminarily confirming that cement-stabilized oil shale semicoke can be used as a subbase course material of a highway or a base course material of a low-grade highway.

Abstract: A discrete element method (DEM) model was used to simulate the development of compaction-induced stress in a granular base course, with and without geogrid reinforcement. The granular base course was modeled as a mixture of uniformly sized triangular particles. The geogrid was modeled as a series of equally spaced balls that interact with each other through long-range interaction contacts. The long-range interaction contact was also used to simulate a deformable subgrade. The compactor was modeled as a solid cylinder rolling at a constant speed. The DEM model shows that the geogrid-reinforced granular base course gains additional compaction-induced stress due to the residual tensile stress developed in the geogrid. The residual tensile stress in the geogrid increases with the number of compaction passes. Parametric analyses were also conducted to assess the effects of geogrid stiffness and subgrade modulus on the compaction-induced stress.

Abstract: The objective of this project was to characterize the freeze-thaw properties of recycled concrete (RCA) and asphalt (RAP) as unbound base and to assess how they behaved in the field for nearly 8 years. This paper includes an examination of existing information, laboratory studies of freeze-thaw behavior, and evaluation of data from MnROAD field-test sections in a seasonally cold region, i.e. , in Minnesota, USA. Test sections were constructed using recycled materials in the granular base layers at the MnROAD test facility. One test section included 100% RAP, another 100% RCA, a third one a 50/50 blend of RCA/natural aggregate, and a fourth one only natural aggregate (Class 5) as a control. The stiffness ( i.e. , elastic modulus) was monitored during construction and throughout the pavement life by the Minnesota Department of Transportation, along with the variation of temperatures and moisture regimes in the pavement to determine their effects on pavement performance. The resilient modulus of each material was determined by bench-scale testing in accordance with NCHRP 1-28a, as well as by field-scale tests incorporating a falling-weight deflectometer. Specimens were subjected to as many as 20 cycles of freeze-thaw in the laboratory, and the change in their resilient modulus was measured. In the field-test sections constructed with the same materials as the base course, temperature, moisture, and field modulus (from falling-weight deflectometer tests) were monitored seasonally for nearly 8 years. From the temperatures in the base course layer, the number of freeze-thaw cycles experienced in the field was determined for each test section. Inferences were made relative to modulus change versus freeze-thaw cycles. Conclusions were drawn for long-term field performances of the recycled base (RAB) in comparison to natural aggregate.

Abstract: The research described in this paper concerns the fatigue life of base course asphalt mixtures. Two mixture types were chosen for analysis: asphalt concrete and High Modulus Asphalt Concrete. Either of them contained different bitumen types, including standard pen-grade bitumens, polymer-modified bitumens (PMB) and so-called highly-modified asphalts (HiMA). Fatigue life tests were carried out and their results were used for fatigue law determination of the mixtures under analysis. Fatigue life analyses were performed both for the analysed mixtures and for typical flexible pavements. The value of the so-called shift factor was estimated to enable application in the design of pavements of the fatigue law parameters determined in laboratory. Two fatigue parameters are proposed in this research: critical strain and fatigue life ratio. They provide a more robust comparison of fatigue life determinations on bituminous mixtures by taking into consideration also the fatigue life of the pavement structure itself. The analyses conducted as part of this research enabled assessment of the fatigue life of asphalt mixtures taking account of the type of both the mixture and the bitumen it contains.

Abstract: Asphalt mixtures are temperature sensitive and have viscoelastic characteristics, so the performances of an asphalt mixture are often affected by nature phenomenon. In Canada, like in many other northern countries, freeze-thaw cycles are a common phenomenon. Also, it is believed that the number of freeze-thaw cycles is increasing with the influence of the climate change. Because of that, the actual methods to predict the pavement distress may overestimate the pavement life. Fatigue distress is a fracture mechanism generated by repeated applications of tensile strains that creates stresses which are less than the strength of the materials. It is initiated at the bottom of the asphalt base layer that is mostly built, in Quebec, with GB20 mix. GB20 is a rutting resistant mix with low binder content that makes it sensitive to fatigue damage. On the other hand, during thaw period, the melting of snow induces bearing capacity loss. The loss of structural support from underlying layers creates a significant increase in tensile stresses at the bottom of the asphalt layers. In addition, there is another possibility of increased tensile stresses due to temperature variations and water expansion/contraction which causes an increase in early fatigue cracking. The effect of temperature and moisture at the bottom of the asphalt layer is totally neglected so far. The thermal variation and moisture contraction/expansion can produce horizontal strains that induce fatigue damage. The effect of environmental freeze-thaw cycle test on the evolution of fatigue cracking has not investigated properly yet. In this research, an asphalt mixture commonly used in the province of Quebec mostly as a base course is studied (GB20). The expansion and contraction of tested specimens are generated by the environmental chamber and measured by strain gauges. Direct Tension-Compression (DTC) equipment is used for the analysis of fatigue, and complex modulus tests. Rapid freezethaw cycles have been implemented to the conditioned specimens in the lab to simulate the daily rapid freeze-thaw cycles. The results demonstrated that the compaction level significantly affects the behavior of the GB20 mix after a large number of rapid freeze-thaw cycles. The effect of rapid freeze-thaw cycles on viscoelastic behavior of the mix was added to the Witczak formula to improve the prediction of the service life of this type of mix. Considering the results of the complex modulus analysis, it was found that the influence of freeze-thaw conditions on the stiffness behavior of the mix is higher with increasing the number of cycles. Regarding fatigue test results, the reference mixture (no freeze-thaw cycles) was more resistant to fatigue cracking than the conditioned mix (mix conditioned with 300 rapid freeze-thaw cycles). The results also indicated that the addition of Aramid Pulp Fiber (APF) could increase the performance and durability of the GB20 asphalt base mix.

Abstract: This paper evaluates the construction quality of aggregate base course layers in terms of the variability and uniformity in density and modulus based measurements. Field and laboratory tests were conducted on 10 aggregate base course layers during HMA pavement construction in Wisconsin. Field tests consisted of in-place unit weight, LWD, DCP, and Stiffness Gauge measurement while laboratory tests included particle size analysis, compaction test, and repeated load triaxial test. Moreover, sensitivity analysis was conducted to assess the influence of the base course layer input parameters on the long-term performance of HMA pavements using the AASHTOWare Pavement ME Design software. Field and laboratory test results demonstrated the existence of high spatial variability in both density (relative compaction ranged from 82.6 to 109.1%, with 17% of test points having values

Abstract: Nowadays, a lot of waste glass produced through different sides of life. Applying sustainability has been widely used in different construction materials and flexible pavement was contained different crushed materials through different studies. Crushed glass, where it is nonmetallic and inorganic, it can neither be incinerated nor decomposed, so it may be difficult to reclaim, has been used as filler, fine and coarse aggregates in the asphalt base course. In this study, various standard asphalt tests, such as stability, flow, density and air voids, have been conducted on reference mix asphalt and mix asphalt with different percentages of crushed glass when it has been used as filler, fine and coarse aggregates in the base course. Generally, the results show good indication, especially when using 10% of the crushed glass instead of coarse aggregate with 40-50 asphalt grades. This percentage improves most characteristics such as strength retained index which indicates better performance than reference mix.

Abstract: The invention provides a pavement structure of an urban road and an urban road, and relates to the technical field of buildings. The pavement structure of the urban road includes a surface course, a toweling course, a base course, a cushion course and a soil matrix which are arranged from top down. The surface course comprises a water permeable brick with the function of intercepting sundries, thetoweling course comprises dry hard cement mortar, and the base course comprises water permeable concrete, the cushion course is a graded broken stone layer. The urban road is provided with the abovepavement structure of the urban road. The pavement structure of the urban road and the urban road relieve the large-pore water-permeable pavement of cement road. When the rainwater enters the base course through the large pores and the large splicing seams of the pavement, the blockage of the pavement structure is easy to occur, which causes the problem that the water permeability of the pavementstructure is relatively short.

Abstract: At the time of industrial development, production of large amounts of wastage required proper disposal. To reduce the disposal problem, utilization of wastage in construction works is a very important aspect. Reuse of industrial waste had gained high momentum for achieving sustainable waste management locally and globally. Keeping this in mind, a research carried out to assess the utilization of molasses, lime and molasses-lime for improving natural gravel for sub-base and base course construction from Jimma Jiren quarry site. The natural gravel from this quarry site is known to have a poor quality, since it did not satisfy the ERA standard specification for sub-base and base course construction. To use Jiren natural gravel as a sub-base or base course construction material, it is necessary to improve its engineering properties. The laboratory test matrix in each test plan included variations in additive type, additive content, and curing period. It was established 8% cane molasses by weight of dry soil as the maximum for effective stabilization of natural gravel for sub-base construction, but not suitable for a base course layer. Results indicated that the natural gravel specimens from Jiren quarry site stabilized with lime, provided higher CBR values than a molasses used alone. On the other hand, replacing 50% of lime content by molasses indicated better results than the performance of either individual additive. Therefore, the natural gravel blended with molasses-lime combination is much better when it used for sub-base and base course construction to treat such an inferior quality of natural aggregates.

Abstract: The invention provides emulsified asphalt and a preparation method, and stable and durable type cement pavement slurry seal sub-seal coat and a preparation method thereof. A prepared slurry seal mixture is paved on a molded lower bearing course of a rigid base course to form the slurry seal sub-seal coat, wherein the slurry seal mixture is prepared from 99 parts of minerals, 1 part of cement, 10 to 15 parts of the emulsified asphalt and 8 to 10 parts of water; the emulsified asphalt is prepared from SBR (Styrene Butadiene Rubber) modified emulsified asphalt, waterborne epoxy resin and a waterborne epoxy curing agent, wherein the SBR modified emulsified asphalt has good adhesion performance with aggregate; when the SBR modified emulsified asphalt is applied to the cement pavement slurry seal sub-seal coat, the flowing water scouring resisting performance of the slurry seal mixture is remarkably enhanced and the stable durability is excellent.

Abstract: Flooding can cause extensive damages in roadways, particularly in those with granular base layers and thin asphalt mix surface layers. The objective of this paper is to present a summary of work conducted on the evaluation of the impact of flooding on pavements. Research shows that flood-induced damage occurs through various ways—weakening and washing away of granular base and soil subgrade layers, washing away of thin surface layers such as seals, and through erosion of subsurface materials near flowing water. Dislocation of concrete slabs due to washing away of subgrade soils during flooding has also been noted. Several models and frameworks have been developed to predict change in structural and surface properties such as roughness due to the impact of flooding. A number of models relating resilient modulus of soil to saturation and matric suction have been proposed. Researches have use both finite difference and finite element models to simulate flow of water through pavements. It has been confirmed that flow under unsaturated conditions is the dominant drainage mechanism in pavements. The role of base course material properties, trench backfill material, and drainage systems has been found to be crucial for drainage. The importance of considering the soil water characteristic curve information and an understanding of change in hydraulic conductivity for different saturation conditions has been emphasized.

Abstract: The invention relates to a vibration mixing wide-width complete-thickness semi-rigidity base course construction process, which comprises: (1) detecting raw materials, and determining a ratio after achieving a qualified standard; (2) carrying out inspection acceptance on a pavement sub-layer before construction, clearing the sub-layer surface, and carrying out measurement lofting to determine theside pile and the middle pile of the pavement; (3) arranging drilling steels on both sides of the pavement at the interval of 10 m so as to arrange a reference line; (4) carrying out dynamic calibration on vibration mixing equipment; (5) pouring various raw materials into the vibration mixing equipment according to the ratio determined in the step (1), and mixing to obtain a mixed material; (6) carrying out water sprinkling and wetting on the sub-layer surface, and spreading the mixed material by using a spreading machine with a power of more than or equal to 250 KW, such that the mixed material is uniformly distributed in the longitudinal, horizontal and vertical directions; and (7) after the thickness of the spread pavement is 40-60 cm and the width is 7-16 m, rolling according to the following manner, and compacting to achieve a designed thickness. According to the present invention, the vibration mixing wide-width complete-thickness semi-rigidity base course construction process has advantages of strong operability, base course construction quality improving, and pavement service life prolonging.

Abstract: This study presents a comparison the strength of rigid pavement using different five base courses. The experiment was conducted at structural and material laboratory, the samples of concrete pavement were represented by concrete cube that placed on different base material. First sample concrete cube was placed directly on the subgrade, the second sample was placed on the granular base course, the third sample was on the granular sub-base course with prime coat, the fourth sample was on the lean concrete, and the fifth sample was on lean concrete separated using impermeable membrane. The result of concrete strength is shown in values of concrete compressive strength, the concrete sample placed on lean concrete base using impermeable membrane has the highest strength compared another concrete on another base course material. The use of impermeable membrane on lean concrete is the possible factor that could produce the highest compressive strength. This membrane would retain cement water in concrete mix, so the strength of concrete is still high.

Abstract: The industry of glass recycling remains a challenge in the province of Quebec due to the lackof equipment required to produce new glass that meets the manufacturing quality. All kinds of glass can be recycled indefinitely because it can retain the similar properties of the reference glass used in the manufacture. Using recycled glass in fabricating new glass needs to separate glass by colors. In the province of Quebec, the collect of recyclable materials is done in a way that glass containers break during transportation and all recyclable materials such as carton, plastic, paper and glass are mixed together. Hence, mixed-colored glass that is unsuitable for producing new containers is utilized in other applications or sent to landfill. This thesis is devoted to using recycled glass (RG) as a replacement for aggregate in pavement structures, which can be a solution for the problems of glass recycling in Quebec. Reusing recycled material in the geotechnical engineering and roadwork has proved a great attraction. However, insufficient knowledge about mechanical characteristics of recycled glass as an aggregate and the shortage of information about the benefit of using it as the aggregate in unbound layers of pavement structures prevents its widespread use. This research program aims to study the advantages and disadvantages of using glass in base course materials from hydraulic and mechanical aspects. The program was divided into three parts. The first part was studying the physical and hydraulic properties of the separate sizes of RG and crushed limestone aggregate, as the reference material. In the second and third parts, the experimental tests were applied to trace the impact of utilizing RG blends with limestone as the unbound granular materials in the pavement structures. A wide range of geotechnical laboratory testing was analyzed to find conclusive evidence for the use of blends of this recycled material in road applications. The findings of this research show that RG blends can provide adequate drainage that is valuable to pavement performance during freeze-thaw cycles in cold region like province of Quebec. The properties of RG aggregate reveals that RG can be safely integrated in pavement base/subbase course regarding hydraulic aspects as well as mechanical aspects. However, it is recommended to limit RG ratio to 25% of fine fraction (0-5 mm) of base course aggregate to keep the least decrease of mechanical properties of blends.

Abstract: The objective of this paper was to assess the possibility of using fine recycled concrete aggregate (RCA) in asphalt mixtures. The experimental research included four asphalt mixtures with partial natural aggregate substitution by fine RCA (0/4 mm), in the amount of 0% (control mixture), 15%, 30% and 45%, by mass. All asphalt mixtures were designed for the base course. The stiffness modulus of asphalt mixtures with RCA was lower compared with the control mixture. The use of fine RCA had no significant influence on the water sensitivity and ranged from -2.4% to +1.7% relative to the control mixture. Resistance to permanent deformation increases with the addition of up to 30% fine RCA.

Abstract: Two-lane highways often consist of aggregate or turf shoulders, which require maintenance on a recurring basis. Rutting and edge drop-offs are the most common performance problems. The maintenance of unpaved shoulders is typically done by placing and compacting more geomaterial. This practice is considered temporary and does not address the cause of the problem; therefore, the problem often recurs. On the other hand, the typical materials used for constructing shoulders contain little organic matter, which makes vegetation growth on these shoulders difficult. Vegetation on the shoulder can prevent erosion due to water runoff and wind, thus it is desirable to maintain a healthy vegetation cover on the shoulders. The previous study showed that an aggregate and topsoil mixture had the same ability to sustain vegetation as a topsoil. The addition of the topsoil into the aggregate lowered the strength of the aggregate, thus geocell could be used to improve the performance of the mixture. This study aimed to evaluate the performance of aggregate, aggregate-topsoil mixture, and geocell-stabilized aggregate-topsoil mixture as the geomaterials for constructing shoulders. Three large-scale cyclic plate loading tests were conducted on sections of 200 mm thick base courses over 5% CBR subgrades (moderate subgrade). The base courses consisted of: (a) 200 mm thick aggregate, (b) 200 mm thick aggregate-topsoil mixture, and (c) 50 mm thick aggregate-topsoil mixture over 150 mm thick geocell-stabilized aggregate-topsoil mixture. The total and permanent deformations of the base course surface under the loading plate were monitored by the actuator. The permanent deformations were used to evaluate the performance of different test sections.

Abstract: The invention provides an entirely-permeable pavement structure sequentially comprising a subgrade structure, a reinforced concrete base course and a water-permeable surface course from bottom to top,wherein water-permeable holes are arranged in the reinforced concrete base course in a running-through manner; and the water-permeable holes are filled with water-permeable materials. The water-permeable surface course of the entirely-permeable pavement structure is a functional course and can meet the requirements of drainage, riding comfort and load transmission. The reinforced concrete base course of the entirely-permeable pavement structure is a structural load-bearing course to ensure the whole rigidity and water permeability of the pavement structure under water immersion conditions. Therefore, the entirely-permeable pavement structure has the advantages of being stable in structure, excellent in performance, not liable to damage, long in service life, suitable for large-scale popularization and application, ingenious in design, simple for paving, low in costs and easy for large-scale popularization.

Abstract: The invention discloses a highway pavement construction method, which comprises the following steps of primarily pressing a roadbed by adopting a vibrating road roller, then finishing repair of the roadbed, and eliminating all crushed matters, bulges and hollowing matters; laying self-made limestone soil on the roadbed to form a pavement bedding; spreading aggregates on the bedding layers by layers by adopting a crushed stone spreader according to a preset width and a preset thickness, fully rolling a laid crushed stone layer by adopting rolling equipment, performing leveling after rolling byadopting a land leveling machine, and uniformly spreading steel fiber reinforced self-compacting cement on the crushed stone layer according to a preset dosage by adopting a powder spreading vehicle;performing mixing to form a pavement base course by adopting a cold recycling machine; and constructing a seal course on the pavement base course, and then laying a pavement surface course. The highway pavement construction method is short in construction period, reduces pollution to environment while reducing the manpower and ensures the loading strength, the fatigue resistance, the compressive strength, the impact strength and the stability of a pavement.

Abstract: The invention discloses cold-mixed asphalt and a cold-mixed cover-face mixture based on a waste asphalt pavement material, and belongs to the field of road engineering. The cold-mixed asphalt is prepared by mixing an active regeneration additive and 90# pavement petroleum asphalt according to a weight ratio of 1:(0.9-1.1). The aggregate of the cold-mixed cover-face mixture is mainly the waste asphalt pavement material. Compared with the prior art, the cold-mixing asphalt provided by the invention can activate the activity of old asphalt in the waste asphalt pavement material, has a good bonding effect, and exerts an active effect on the use durability of the mixture. The cold-mixed cover-face material has good elasticity and self-healing capability and can reduce the reflection cracks of pavement construction, and the material has good waterproof capability, can reduce the invasion of road-surface water on the base course, and can prolong the service life of roads.