Abstract: In light of the increasing cost of hot-mix asphalt (HMA) mixtures and the limited availability of good materials, cold in-place recycling (CIR) offers an attractive alternative for rehabilitating asphalt pavements. Because of its limited performance history and the unavailability of a standard mix-design procedure, the use of CIR mixtures has been limited to low-and medium-volume roads. For more than a decade, many highway agencies have experimented with or used CIR mixtures and reported numerous successes. The Nevada Department of Transportation (NDOT) is currently using CIR on low- and medium-volume roads. The CIR layer is treated as a stabilized base course followed by a thin HMA overlay. As part of this program, NDOT developed a mix-design procedure based on the Hveem mix-design method to establish the optimum moisture and emulsion contents. The design procedure evaluates the moisture sensitivity of the CIR mixture and determines the need for lime treatment of the CIR mix. The basic concept of the mix...

Abstract: Class C fly ash is a coal combustion product from lignite or subbituminous coal obtained as a result of the power generation process. In recent years, efforts were taken to incorporate self-cementing fly ash into full-depth reclaimed (FDR) material to improve the structural capacity of asphalt pavement base layers. In this study, existing asphalt pavement in County Trunk Highway (CTH) JK in Waukesha County, Wisconsin, was pulverized in place and mixed with fly ash and water to function as a base course. To evaluate the contribution of fly ash to the structural performance of the pavement, nondestructive deflection tests were performed with a KUAB 2m falling weight deflectometer on the outer wheelpath 4 days and 1 year after construction. The modulus of fly ash-stabilized FDR base course increased by 49% 1 year after construction. The structural capacity of the fly ash-stabilized FDR base course in CTH JK also has increased significantly as it ages, because of the pozzolanic reaction. The results of this study indicate that the FDR mixes with self-cementing fly ash may provide an economical method of recycling flexible pavements and reduce the need for expensive new granular base courses for road reconstruction.

Abstract: Use of incinerator ash in construction of highway pavement layers may have the potential to significantly reduce the quantity of ash that must be disposed of. However, the physical properties of ash are not optimal for construction of normal asphalt pavement. When designed and applied properly, foamed asphalt provides a way of obtaining good coating on granular materials made from ash and hence adequate cohesion of pavement materials. Also, foamed asphalt provides a way of using materials with relatively high percentage of fines and moisture content. This paper briefly reviews foamed asphalt and its use, production of aggregate from incinerator ash, and describes design, construction, and evaluation of a parking lot pavement using foamed asphalt-treated ash. Based on the results obtained from mix designs it was recommended that 2% lime be added to a mix with 100% ash (at optimum moisture content), and that 1% lime be used when 75% ash is combined with 25% recycled concrete-the recycled concrete being minus 12.5 mm material. For both 100% ash and the combination of 75% ash and 25% recycled concrete (minus 12.5 mm material) a design foamed asphalt content of 4.5% was recommended. Laydown and compaction of experimental foamed asphalt treated recycled ash mix was completed without any major problems. Results of Benkelman beam test showed that the foamed asphalt treated recycled ash mix layer cured and gained adequate stiffness within a period of 24 h.

Abstract: The demand for quality natural aggregates for use in pavement construction is approaching a critical state in some parts of New Zealand and other countries around the world. The search for alternative sources of aggregate to minimize the utilization of natural aggregates and provide a high quality substitute has led to slag. The purpose of this study was primarily to examine the engineering, environmental and economical issues relating to the utilization of melter slag as a base course material. New Zealand pavements are predominantly thin-surfaced unbound granular flexible pavements where the main design criterion is the vertical compressive strain at the top of the subgrade imposed by each axle load. Laboratory testing used Repeat Load Triaxial apparatus to determine the resilient modulus and permanent deformation characteristics of the melter slag aggregate and two traditional aggregate materials. The principles of multi-layer elastic theory were then used in a pavement design exercise to determine the...

Abstract: Asphalt pavement includes concrete sabbase with processed by-product of manufacture of crushed limestone of regular sizes as a coarse aggregate. This aggregate is defined as enriched limestone waste of grading intermediate between the coarse and fine aggregates. The specified compressive strength and modulus of rupture of this concrete make up to 5,000 and 750 psi, respectively. The choice of the thickness and modulus of rupture of concrete subbase and the thickness of asphalt surface course should be provided by the trial-and-error method basing on the required capacity of asphalt pavement as a composite structural member to minimize the initial cost of pavement. Reduction of cracking of the asphalt surface course by limitation of its deformations due to the choice of the reasonable rigidity of the base course should reduce the maintenance cost of pavement. This pavement is intermediate between rigid and flexible pavements and can be defined as semi-rigid or semi-flexible.

Abstract: Numerous embodiments of one or more layers of void-maintaining synthetic drainable base courses (“VMSDBC's”) are provided as incorporated into landfills and other waste containment facilities.

Abstract: The utility model relates to an anti-crack internal insulation wall, comprising a base course wall, an interface layer, an insulating layer, a leveling blanket, an anti-crack protective layer, an interior wall putty layer and a facing layer; the anti-crack protective layer is formed by binding an anti-crack gypsum leveling blanket, an adhesive layer and non-woven fabric in sequence. The wall performs base course wall is treated in the construction, and interface mortar is fully applied on the base course wall; the construction of the insulating layer and the leveling are carried out; the anti-crack gypsum is covered from 3mm to 10mm and the leveling is carried out, then the non-woven fabric is pasted by adhesive; soft putty is used to knife coating the interior wall; the construction of the facing layer is carried out. The utility model solves the problems of easy cracking of the insulating anti-crack protective layer and high cost; by replacing the glass fiber cloth, not only the cracking is prevented, the anti-crack protective layer is also thinner, so the material cost is reduced, and the anti-crack performance is strengthened.

Abstract: PROBLEM TO BE SOLVED: To provide a labor-saving track supporting rail ties by a filling layer formed on a base course constructed of viscous soil, and maintain a repair effect of the damaged base course for the long term. SOLUTION: A powdery high-plasticity material (such as bentonite powder or the like), which is provided with water-absorbing swelling characteristics, is infused into the hollow 4 of the base course 2. After that, a filling material for repair (such as cement asphalt mortar) is infused into the hollow 4. Then a protective layer 13 for protecting the surface of the base course constructed of the high-plasticity material is integrally formed on the surface of the base course 2. Consistency properties Ic of the protective layer 13 for protecting the surface of the base course are 10 or less (preferably 5 or less). Then Ic=0.73WL-Ip (WL:a liquid limit, Ip:a plasticity index). Thus, the discharge of the mud from the surface of the base course 2 is prevented, and the generation/ growth of a new hollow on the surface of the base course 2 is inhibited. Furthermore, since the high-plasticity material is powdery, a small amount of the high-plasticity material is fine even if the hollow is large, thus the material cost and the construction cost are controlled. COPYRIGHT: (C)2006,JPO&NCIPI

Abstract: As base course material, porous concrete withstands the repeated action of traffic and temperature,so the fatigue property should be considered in structure design According to indoor flexural fatigue tests,authors analyzed the probability distribution of fatigue life,drew that the fatigue life of porous concrete obeys the two-parameter WEIBULL distribution, and built two types of fatigue equation under different stress level and equivalent stress level Authors also analyzed the influencing factors of fatigue life and corresponding measures to reduce the variability, and got that the fatigue property of concrete is better than the semi-rigid base materials At last, with the fatigue equation,authors built the fatigue stress coefficient which was used in the load stress calculation for porous concrete as undersurface of cement concrete pavement, and the structure coefficient of flexural tensile strength which was used in the flexural stress check for porous concrete as base of asphalt pavement

Abstract: Asphalt trial mixes for rehabilitation of the 03 - 21R runway of Johannesburg International Airport, were constructed after complying with laboratory test criteria. Subsequently, MMLS3 field testing found rutting performance of the mixes suspect. Gyratory compaction and dynamic creep performances did not predict this. The design process was then reversed by conducting MMLS3 tests on laboratory compacted briquettes to evaluate field performance. The selected mixes were plant produced, paving trials constructed and cores tested to evaluate performance. Protocols for evaluation were based on performance of full-scale pavements under MMLS3 field trafficking, and actual performance data of similar pavements under conventional truck trafficking with adaptations for airport trafficking. Follow-up MMLS3 tests on field cores were conducted to investigate early rutting under aircraft trafficking during hot weather conditions. 1. BACKGROUND Traditionally the contractor is required to develop an asphalt mix design that complies with specific empirical and or performance related criteria. However, it has been found that compliance with these design criteria, does not necessarily guarantee future performance of the asphalt mix. This is specifically a problem where it concerns resistance to deformation and distress due to wet trafficking. The engineer is faced with the dilemma that new mix compositions (or designs) can only be assessed after having been exposed to traffic loading over a period of time. For this reason, the specification calls for rut resistance tests to be performed as a final check before the mix can be approved. This paper discusses a case study in which accelerated pavement testing (APT) using the model mobile load simulator (MMLS3), was used to address this problem (ITT, 2003). Asphalt surfacing and base course trials for rehabilitation of the 03L - 21R runway of Johannesburg International Airport (JIA), were constructed with approval of the Engineer, after complying with all laboratory specification criteria. Subsequently, rutting performance of the mixes proved to be suspect under MMLS3 field trafficking. Gyratory compaction and dynamic creep performances did not predict excessive deformation under the MMLS3 trafficking. The contractor was then obliged to speed up the design process to submit suitable alternative mix designs. A decision was taken to reverse the design process by using MMLS3 tests on laboratory compacted briquettes to evaluate rutting performance in the field under different selected climatic conditions. Various mix compositions were tested in the laboratory. With due consideration for the ideal conditions under which these briquettes were manufactured, the most suitable mixes were reproduced in the plant, paving trials were constructed and cores were tested to validate satisfactory rutting performance of the selected mixes.

Abstract: PROBLEM TO BE SOLVED: To provide a method of manufacturing recycled asphalt concrete aggregate for obtaining the recycled asphalt concrete aggregate usable without hindrance as aggregate for concrete, aggregate for a base course and aggregate for asphalt concrete by positively separating a coal tar component and an aggregate component of an asphalt concrete waste material. SOLUTION: The method of manufacturing the recycled asphalt concrete aggregate comprises an oil submersion process B for obtaining the aggregate component 11 free from the coal tar component from an asphalt concrete lump 1 by submerging the asphalt concrete lump 1 in heated oil 3 to melt the coal tar component in the oil, and a mixing-agitating process C for reducing (eliminating) oil sticking to the surface of the aggregate component by mixing and agitating aggregate in the aggregate component to apply oil sticking to the aggregate component, to the mixing aggregate 4. COPYRIGHT: (C)2006,JPO&NCIPI

Abstract: In the past five years, over 25 structures in the states of California, Oregon, and Washington, have been supported by Rammed Aggregate Piers. constructed in granular soils. The piers are installed by drilling 60 to 90 cm diameter holes and ramming thin lifts of highway base course stone within the drilled cavities. The elements are used to support conventional shallow footings. The system is unique and innovative because it incorporates features associated with the design and construction of shallow and deep foundation systems. Accordingly, the design procedures include concepts derived from conventional shallow foundation design, historical stone column soil improvement system design, and cast-in-drilled-hole concrete shaft design. Unlike design values for drilled deep foundation systems, which are well-documented in the literature, parameter values for rammed aggregate piers are established from the results of modulus tests conducted at each project site. This paper presents results of 19 rammed aggregate pier modulus tests performed at sites underlain by granular soils. Test results are correlated to matrix soil characteristics and length of the piers. This paper is of particular significance because it presents a database of in-situ modulus values used in the design of a cost-effective and increasingly popular drilled foundation system.

Abstract: PROBLEM TO BE SOLVED: To prevent the separation of an elastic layer from an underlayer caused by air retained in a pavement structure with the elastic layer coated on the underlayer comprising an asphalt mixture SOLUTION: A subbase course 1, a base course 2, a foundation course 3 consisting of a permeable asphalt mixture, a surface layer 4 consisting of an impermeable asphalt mixture, an unevenness adjustment layer 5 for adjusting the surface of the surface layer 4 levelly, and the elastic layer 6 formed of resin plate members, are sequentially layered In this pavement structure, moisture permeating between the unevenness adjustment layer 5 and the elastic layer 6 flows down to cavities 3c formed in the aggregate of the foundation course 3, from a plurality of small holes 4c passing through the surface layer 4 and the unevenness adjustment layer 5, and permeates into the subbase Consequently, rainwater or the like hardly stays between the elastic layer 6 and the unevenness adjustment layer 5 to reduce the rise of steam pressure due to the evaporation of the moisture Further, even if high steam pressure is generated between the elastic layer 6 and the unevenness adjustment layer 5, gas is released into the cavities in the foundation course through the small holes COPYRIGHT: (C)2005,JPO&NCIPI

Abstract: Aiming at the problems of shrinking cracks in the cement-stabilized macadam base course,through substantive experiments this article discusses the influence of the factors such as the cement content, fly ash content, aggregate gradation and admixture content on drying and temp performances of the cement-stabilized macadam mixture base course, and proposes the suggested aggregate gradation and content of each factor.

Abstract: In this paper,the cement stabilized crushed-stones used as road base material for Wu-Xuan Expressway in Anhui Province is regarded as research object.According to the experiments,the strength,delay-time and contract characteristic of the material are tested and analyzed.And from the construction craft and organization,the key points of the construction quality control are researched and put forward in accordance with result of the laboratory and field tests.

Abstract: PROBLEM TO BE SOLVED: To solve problems in conventional permeable road pavement structure wherein a surface part is deteriorated with age under the irradiation of sunlight and the action of oxygen in the air, which causes notable degradation of characteristics to lower the bonding strength of a permeable resin concrete layer and to accelerate discoloration, damage and wear of a surface layer part, and in the case of bonding aggregate with epoxy resin, a construction cost is high due to the high cost of epoxy resin. SOLUTION: A mixture obtained by kneading cement, aggregate, water and lime is placed on a base course to form a permeable concrete layer, and the surface of the permeable concrete layer is covered with polyurethane without closing cavities formed in the permeable concrete layer and communicating with the base course. The permeable pavement structure with excellent fading resistance and weather resistance can thereby be easily constructed at a low cost. COPYRIGHT: (C)2004,JPO

Abstract: PROBLEM TO BE SOLVED: To provide a base course material which makes a base course more compact thana conventional base course material of only natural crushed stones, makes a coefficient of a load bearing capacity of the base course higher and maintains strength even after the execution of work, and a backfill filler which absorbs a topographic change. SOLUTION: A mixture, which is obtained by mixing a cement-based solidifying material, a reinforcing material and water into mud of rock-like powder, is deaerated by vacuum suction, cured, hardened and crushed, so as to be used as a granular recycled material for construction. The granular recycled material, whose weight is 10-50% of total weight, and the natural crushed stones and a material equivalent to the crushed stones, which serve as the other materials, are mixed together and used as the base course material A and the backfill filler B. The granular recycled material is deformed or crushed among the natural stones etc., so that granules can be consolidated and so that the coefficient of the load bearing capacity of the base course can be made higher; and an increase in strength can be expected because the hardening is advanced even after the execution of the work. The topographic change is absorbed by the backfill filler B so as not to exert an influence on an underground structure. COPYRIGHT: (C)2004,JPO

Abstract: Approach to strengthening old pavement structure that paves high void asphalt macadam with top-size aggregate 37.5 cm on existed pavement instead of semi-rigid base,can prevent base reflection cracking and drain water from base layer.This mix must be used high viscous asphalt to increase asphalt membrane thickness.The mix design is based on aggregate inter-lock method and use leakage test to determine asphalt content.Construction technique used asphalt macadam as flexible base layer is concluded through field test road.Field data demonstrates that this mix used as flexible base in pavement reconstruction can satisfy pavement strength,high-temperature stability requirements,drain water and prevents reflection cracking effectively.

Abstract: In spite of continuously increasing loads of traffic areas and the resulting demand for high-quality construction materials, particularly for asphalt wearing courses, the normal structure of asphalt pavements in Germany has currently been nade of a minimum 4 cm thick wearing course and an 8 cm thick asphalt binder layer. Since 1995 there is a possibility to produce the asphalt wearing course in one single process using a special construction method. From that time on, the characteristics of both layers can be optimized and the thickness of the wearing course can simultaneously be reduced to 2 cm. This type of construction is called "Compact Asphalt". Meanwhile, the Compact Asphalt stands for a new generation of permanently light, noise-reduced and deformation-resistant asphalt pavements of good grip. For the covering abstract see ITRD E121480.

Abstract: PROBLEM TO BE SOLVED: To form a pavement surface of good appearance without any crack, warp, or the like without influencing the putrefying speed of wood chips by the impregnation of a binder. SOLUTION: This wood chip pavement is constituted to cover a clearances formed between a pavement material 12 and each edge member 10 defining the width direction of a pavement area of a base course surface 4, with a covering member 14 for covering a boundary line between the pavement material 12 and the edge member 10. Floatation is thereby limited by the covering member 14, and appearance is not degraded. Further, since the pavement movement of the base course surface 4 is forcibly corrected only in a direction of the base course surface 4, internal distortion is relieved by a secular change to eliminate floatation of pavement from the base course surface 4. Since the expansion/contraction of pavement of the base course surface 4 is allowed in the direction of base course surface 4, the pavement surface 4 without any crack, warp, or the like can be formed. In addition, since the binder is not used for coating or impregnation of wood chips, the putrefying speed of wood chips is uninfluenced. COPYRIGHT: (C)2005,JPO&NCIPI

Abstract: Reflecting cracks of semi-rigid asphalt pavement is caused by semi-rigid base temperature change. Flexible base between semi-rigid base and asphalt surface could efficiently avoid or reduce reflecting cracks of asphalt pavement. According to heat exchange theory, temperature status of semi-rigid base top in Jilin Tonghua test road which has three kinds of pavement structures was contrasted by applying finite element method. The result indicated that flexible base could efficiently ameliorate temperature status of semi-rigid base of asphalt pavement, therefore could reduce or avoid reflecting cracks of asphalt pavement.

Abstract: PROBLEM TO BE SOLVED: To utilize old tires and agricultural vinyl sheets as construction materials minimizing influence on the environment. SOLUTION: The cut agricultural waste vinyl sheets are inserted in the old tire, which is covered with plastic of band shape or covering the whole tire and utilized as a backing base course material of a concrete plate or the like. At the same time, rainwater staying on the road surface is temporarily retained inside the old tire to provide a function as a water storage tank. COPYRIGHT: (C)2004,JPO

Abstract: PROBLEM TO BE SOLVED: To attain instant snow melting to reduce an economical burden in a system for melting snow by applying heat to the surface of a base course. SOLUTION: A heat storage layer is provided under the surface of the base course, and a heating means is disposed in a position in contact with the heat storage layer while providing a plurality of heat storage conduction pipes for conducting heat in the heat storage layer and heat generated by the heating means, into soil below the heating means. The heat storage conduction pipe is provided with air releasing openings in the upper end part and the lower end or the side face. The heat storage layer is formed using sand, gravel, volcanic ashes, concrete, or the like. The vertical design dimension is set to 30cm-60cm, and a temperature sensor is provided inside. The heating means is driven at 20°C. COPYRIGHT: (C)2004,JPO

Abstract: A theoretically-based design method for the thickness of the base course of unpaved roads is developed that considers distribution of stress, strength of base course material, interlock between geosynthetic and base course material, and geosynthetic stiffness, in addition to conditions considered in prior methods: traffic volume, wheel loads, tire pressure, subgrade strength, rut depth, and influence of the presence of a reinforcing geosynthetic (geotextile or geogrid) on the failure mode of the unpaved road or area. In this method, the required base course thickness for a reinforced unpaved road is calculated by a unique equation, whereas more than 1 equation was needed with earlier methods. This design method was developed for geogrid-reinforced unpaved roads. However, it can be used for geotextile-reinforced unpaved roads and for unreinforced roads with appropriate values of relevant parameters. The calibration of this design method using data from field wheel load tests and lab cyclic plate loading tests on unreinforced and reinforced base courses is presented in a companion paper by the authors of this paper.

Abstract: This paper presents the overall performance of hot mix asphalt mixtures containing crumb rubber modified (CRM) binders as compared to similar mixes with conventional binder under accelerated loading. Three test lanes were constructed at the Louisiana Pavement Research Facility. The first lane consisted of asphalt rubber HMA (AR-HMA) wearing course, conventional HMA binder course and conventional base course. The second test lane consisted of conventional HMA wearing course and conventional binder course, and ARHMA base course. The third test lane was the control one and consisted of conventional mixes in the wearing course, binder course, and base course. The performance evaluation measured included rut depth and laboratory mixture performance tests. In general, the test lane containing AR-HMA mix in the wearing course showed similar rut depth, and pavement stiffness to the control test lane (with conventional mixtures), whereas, the lane containing AR-HMA mix in the base course had an improved rut resistance as compared to the control lane.

Abstract: Measurements have shown that the International Roughness Index (IRI) values for the urban transport facilities predicted for reconstruction range from 5m/km to 14m/km, and for new or already reconstructed ones the values vary about 2m/km. Usual ways of repair of the pavement facilities structures in the city of Zagreb are: 1) replacement of already existing asphalt layers with a new bituminized crushed stone material base course and wearing asphalt concrete layer and 2) performance of the new pavement structure (layer of mechanically compacted course of grain stone material, bearing layer stabilized by hydraulic binder, bearing layer made of bituminized crushed stone material and a layer of splitmastix asphalt wearing course - SMA. As a large number of urban facilities are planned for reconstruction, the study was conducted to justify each repair mode. The study proposes the IRI values, obtained from the investigation measurement results upon which the reconstruction could be carried out to get the aimed IRI values ranging up to 2m/km in the end point.

Abstract: Neoprene latex modified emulsified bitumen and fine aggregate are used to prepare a new type of stress-absorbed material, which has strong ability of anti-reflective cracking on asphalt concrete over layer-constructed upon a semi-rigid type base course or cement concrete pavement block. Experimental results demonstrate the stress-absorbed material have excellent mechanical properties including a low modulus of elasticity, high ultimate tensile stress and strain, and a strong distortion ability. Stress concentration in asphalt over layer originated by temperature changes and traffic loads can be alleviated.