Road Pavement Layers Research Articles

Calcium bentonite and sodium bentonite as stabilizers for roads unbound

Several technologies are currently available to stabilize the unbound layers of road pavements. The use of these solutions, often manufactured by means of chemical processes, is steadily increasing worldwide. As an alternative natural resource, the use of bentonite represents a valid option when it comes to road stabilization and its application in this context is still relatively unexplored. This study characterises the use of calcium based bentonite and sodium based bentonite to stabilize a typical road base layer. Considering two types of aggregates with different geological origin, the laboratory investigation is performed on dry specimens by means of repeated load triaxial tests, which assess the enhancement in stiffness and resistance to permanent deformation. The findings show that both the investigated types of bentonite are suitable for road stabilization. Even if negligible from a road engineering standpoint, the performance stemming from calcium bentonite was slightly better than the one pertaining to sodium bentonite when it came to the increase in resilient modulus. • Bentonite clay is a natural effective resource to stabilize unbound layers of roads. • Repeated load triaxial tests evaluate modifications in stiffness and deformation. • The performances related to calcium bentonite and sodium bentonite are compared.

ИСПОЛЬЗОВАНИЕ ГРУНТОВ, УКРЕПЛЕННЫХ ВЯЖУЩИМИ, В КОНСТРУКЦИИ ДОРОЖНЫХ ОДЕЖД

The article deals with the use of binder-strengthened soils as layers of road pavement. Particular attention is paid to the problems of application of this technology in modern road construction. The analysis of methodological researches of scientists has been carried out, on the basis of which the conclusion about the necessity of creating the regulatory framework devoted to the reinforced soils which must include the basic technical requirements, necessary data for calculations, recommendations for application and other methodical documentation has been made.

Assessment of Lime Stabilized Soils Modified with Egg Shell Ash for Road Construction

The need to have in-depth knowledge about the Engineering properties of soil and the sub-soil condition for road construction especially in the southwestern Nigeria brought about this study. Some strength properties (California Bearing Ratio (CBR), Compaction, Unconfined Compressive Strength (UCS), and direct Shear tests) of lime stabilized soils modified with Egg Shell Ash (ESA) were assessed. Soil samples were obtained from each state in the study area and transported to the laboratory, where they were stabilized with 6% lime and 0 to 10% ESA before the above-mentioned tests was conducted on them. The local additive was also subjected to a chemical analysis. Results showed that ESA additive has low SiO2 and high CaO compounds. Increase in ESA resulted in increase of all the strength properties (Maximum Dry Density (MDD), CBR, UCS, Cohesion (C), Shear strength (S) and Angle of Internal Friction (ϕ)) and reached peak at 8% ESA, thereafter decrease; albeit, Optimum Moisture Content (OMC) decreases. After the improvement process, almost all the unsuitable soil samples became suitable for use as pavement layer materials. Consequently, a blend of 6% lime and 8% ESA content is recommended for soil improvement, especially for road pavement layers in southwestern Nigeria.

Easy Way To Determine The Feasibility Of Coarse Aggregate On All Pavement Layers Using The Los Angeles Tatonas TA-700 Machine

The use of coarse aggregate with poor quality can cause bumpy roads, cracked roads, potholes, and others. Coarse aggregate wear is an indicator of the aggregate resistance index against friction with other objects. Any aggregate to be used in a pavement mix must meet the wear requirements. Low wear causes the aggregate to be easily crushed when exposed to friction and has an impact on a low level of stability. The purpose of this research is to determine the feasibility of coarse aggregate in Kedak Village, Kediri. One of the feasibility of coarse aggregate is reviewed based on wear with abrasion testing. This research was conducted by using an abrasion test using the Los Angeles TA-700 machine and SNI 2417:2008 as a reference. The specimens were taken at random and met the criteria for passing the number 3/4 sieve and stuck on the 2500 gram sieve number 1/2 and the aggregate that passed the 1/2 sieve was stuck on the 3/8 sieve as much as 2500 grams. The results obtained stated that the average wear of the abrasion test was 26.6%. Based on these results, the aggregate can be said to be feasible because it does not exceed 40% in accordance with the provisions of the 2018 Binamarga General Specifications. So that coarse aggregate from Kedak Village, Kediri can be used for all mixtures of road pavement layers.

Forensic Study on Federal Road Pavement Failures at Rengit and Semerah, Batu Pahat

Forensic investigations in engineering term may be conducted to identify the causes of failure to facilitate the design of proper repairs, or to improve the performance or lifespan of a component, assembly, or structure. This paper presents the combination of geotechnical investigation and geophysical survey method as a forensic tool to predict the causes of pavement failure occurred along the coastal area of federal road FT005. The number and type of field testing are varying on each selected study area at Rengit and Semerah, Batu Pahat as this location constructed on soft soil area. Non-destructive testing (NDT) method using electrical resistivity tomography (ERT) were chosen to be applied at the worst severity of the road failure. Three number of resistivity lines of 100m and 200m were laid out using ABEM Terrameter LS2 with gradient method of electrode arrays covering up to 40-meters depth. Then, further testing of destructive testing (DT) method using borehole drilling conducted near the ERT lines to obtain soil profile with SPT N-value measurement. The disturbed and undisturbed samples were obtained to carried out laboratory test for soil classification. After that, inspection of road pavement layers were implemented at five number of trial pit tests which excavated up to subgrade layer to determine the thickness of the materials used in road construction. Three number of mackintosh probe test were also conducted on top of the subgrade layer after the trenching to obtain the strength of the subgrade layer. The results presented showed that severe longitudinal cracking were the predominant premature failures on the roads studied due to settlement effect of soft soil. The analysis obtained from RES2DINV program stated that the subsurface profiling was dominantly in saturated condition which the resistivity value was less than 100 ohm.m. From the SPT N-value it is observed that, the very soft soil layer is up to 8 m followed by the soft to stiff clays soil. Another cause of failure was resulted from the differential settlement due to the effect of different design of road construction with varies material used. The reliability and efficiency of the instruments used were also discussed in this study.

Аnalysis of methods of calculating road structures based by shear resistance in the soil

Introduction. Checking the soil of the subgrade and the layers of road pavement made of loosely cohesive materials by shear resistance is one of the three mandatory conditions for calculating road clothing according to strength criteria. The methodology for checking the soil of the subgrade and the sandy layers of the road pavement is constantly being modified, which is why changes concerning certain calculation details appear in each new version of the regulatory document. The purpose of this work is to analyze the advantages of the classical solution of A.M. Krivissky and to reveal the essence of the errors made in subsequent modifications of this calculation.Materials and methods. The analysis of solutions is carried out from the standpoint of compliance with the basics of mechanics. It is shown that the calculation of the total shear stress in the classical solution of A.M. Krivissky is performed in accordance with the principle of force superposition, which consists in calculating the components of the stress tensor from each force (time load and the own weight of the layer materials) separately, followed by summing the corresponding components. In this case, the active shear stresses from the temporary load and the own weight of the materials are calculated as the equivalent stress of the Mohr-Coulomb criterion. The calculation of these two components of the total shear stress is performed at the same value of the internal friction angle. Since the angle of inclination of the sliding surface to the main axes is determined by the sum or difference of 45 degrees and half of the internal friction angle, the tangential and normal stresses, which are components of the active shear stress, both from the temporary load and the own weight of the materials, are determined for the same shear surface rotated to the main axes at the same angle. In the current normative calculations, the active shear stresses from the temporary load and the own weight of the materials are determined at different angles of internal friction. This means that the active shear stresses from the temporary load and the own weight of the materials act on two different shear surface rotated to the main axes at different angles. Such stresses cannot be summed up or compared with each other. In addition to this error of the normative calculation methods, their other disadvantages are given.Results. As a result of a detailed analysis of the known modifications of the classical solution, obvious contradictions to the principles of continuum mechanics are established. As an alternative to modern calculation criteria for shear resistance, the article presents criteria for soil strength in which the shear stress exceeds the equivalent stress in the Mohr-Coulomb criterion. The principle of deducing formulas for calculating the first critical load and the total shear stress from the strength criteria under consideration is shown.Conclusion. Conclusions are drawn about the need to return to the classical solution obtained by specialists of the Leningrad School of the USSR, or to develop a fundamentally new solution based on a new plasticity condition in which the total shear stress exceeds the similar characteristic of the stress state of the original Mohr - Coulomb criterion.

Effect of Assumed Boundary Conditions in Numerical Model of Road Pavement-Mining Subsoil System on Criterial Values Used in Design Using Mechanistic Methods

Underground mining brings benefits in the form of the extracted mineral. The negative effects of mining exploration are deformations of the rock mass, which also cause deformations on the ground surface. There are continuous deformations, discontinuous deformations and mining-induced tremors. Recommendations regarding the protection of the structure of cubature building against the negative effect of mining operations are discussed in detail, for example, in the recommendation published by the Building Research Institute (ITB) in Warsaw. In the case of road structures, the situation is different. Firstly, there are no general rules that would provide clear guidelines for the procedure for designing road pavement in mining areas, similarly to cubature buildings. Secondly, in the computer programs used for the individual design of road pavement, it is not possible to assign additional actions, including mining impact. Therefore, in order to analyze the behavior of the pavement-mining subsoil system, an advanced numerical analyze should be carried out. In this case, the subsoil thickness, the boundary conditions and the constitutive relationships of the materials of the road pavement layers and subsoil should be determined. This paper presents an attempt to select kinematic boundary conditions for the FEM model of the road pavement-mining subsoil system, analogically to the model of the building-mining subsoil system. The paper is aimed at assessment of the influence of kinematic boundary conditions selection on the criterial values that are taken into account during the design process of road pavement using mechanistic methods. For this purpose, three cases were considered: (i) horizontal mining strain (εdesign ), (ii) curvature of surface (Kdesign ), (iii) combined impact of these actions. In these cases, each time vehicle wheel load was assumed. Based on the analyzes, the computational horizontal strain of the mining area εcomp is decisive when assessing the criterial values taken into account in the design process of road pavement structures.

Structure formation of dispersion hardened organomineral mixtures

The relevance of the work is determined by the need to improve the properties of the road pavement layers. Under conditions of increasing carrying capacity of vehicles and traffic intensity, pavements designed and constructed in accordance with the regulatory documents are destroyed without reaching the required service life. The pavement reinforcement with chemical fibers is one of the ways to solve this problem. The aim of this work is to study the structure formation of dispersion reinforcement of the pavement layers made of organomineral mixtures. Theoretical calculations are presented for the structural formation with directional reinforcement by using meshes and interlayers with dispersed reinforcement. It is shown that directional reinforcement of the structural layers provides compensation of tensile stresses only at the bottom layer, where the mesh locates. At the edges of the deflection bowl in the upper layer, tensile stresses are not compensated because the reinforcing mesh locates at the bottom layer. With dispersed reinforcement, chemical fiber penetrates in the structural layer, including its top and perceive tensile loads and reduce the likelihood of cracking. The implementation of the liquidphase method of dispersed reinforcement of organomineral mixtures improves the bitumen adhesion to the fiber surface of the dispersed reinforcement.

Engineering Properties of New-Age (Nano) Modified Emulsion (NME) Stabilised Naturally Available Granular Road Pavement Materials Explained Using Basic Chemistry

Nanoscale organofunctional silanes have been developed, tested and successfully applied to protect stone buildings in Europe against climatic effects since the 1860s. The same nanotechnologies can also be used in pavement engineering to create strong chemical bonds between a stabilising agent and granular material. The attachment of the organofunctional silane to a material also changes the surface of the material to become hydrophobic, thereby considerably reducing future chemical weathering. These properties allow naturally available materials to be used in any pavement layer at a low risk. In the built environment, scientists soon determined that the successful use of an organo-silane depends on the type and condition of the stone to be treated. The same principles apply to the implementation of applicable nanotechnologies in pavement engineering. Understanding the basic chemistry, determining the properties of the stabilising agent and the organofunctional modifying agent and the chemical interaction with the primary and secondary minerals of the material are essential for the successful application of these technologies in pavement engineering. This paper explains some basic chemistry, which fundamentally influences engineering outputs that can be achieved using New-age (Nano) Modified Emulsions (NME) stabilising agents with naturally available granular materials in all road pavement layers below the surfacing.

Cement-Treated Volcanic Scoria for Low-Traffic Road Pavements in the Azores Archipelago.

The Azoreans rely on an extensive network of rural roads for the most of the rural population’s activities (primary sector) and accessibility. To rehabilitate and maintain this network, asphalt concrete and crushed rock aggregate are usually used. However, in the region, the application of such paving technology can be extremely costly. It requires specialized contractors, dedicated equipment and raw materials that must be imported to most of the islands. Therefore, the use of locally available materials would result in more flexibility and fewer costs for planned interventions. In the Azores, known as bagacina, the volcanic scoria is a pyroclastic material, generally highly abundant in volcanic islands. This natural aggregate is inexpensive, easy to extract, and presents good geotechnical characteristics. However, due to its porous nature, it generally does not comply with the current specifications for pavement materials. Therefore, this study aims to evaluate cement-treated volcanic scoria to be used as low-traffic road pavement layers. The geotechnical properties and mechanical performance of the two types of scoriae were analyzed. As a result, both types of scoriae presented good behavior, according to the expected for a cement-treated material, and proved to be a suitable alternative for road pavements in the Azores Archipelago.

Feasibility Study Comparison of Pavement Designs Using Local Materials

The possibility of using local materials in the construction of structural layers of pavement is considered in the paper. The paper presents a method of technical and economic analysis, for which it is necessary to know the calculated deformation moduli of the materials being compared. Knowing the turnaround time for each of the options under consideration, it is possible, by comparing them with the payback periods, to more fully identify the technical and economic features of such options. The main criterion for the admissibility of the use of local material in the corresponding structural layer is the equal strength of pavement structures or individual structural layers made of local and imported materials. The criterion of economic feasibility of using local material can be written as an inequality. Using the principle of equivalence of systems, it is possible to replace individual structural layers of pavement, made of certain materials, with equivalent layers of stiffness from other materials, increasing or decreasing their thickness, depending on the strength characteristics of the materials themselves. The main condition for the technical feasibility of using local material has been determined on the basis of the condition of equal strength structures made from local and imported materials. A schedule for preliminary determination of the technical and economic feasibility of using local materials in the structural layers of road pavements has been built. The total value of the investment costs can be used as an additional criterion for the economic benefits of the compared options.

A Practice for the Application of Waste in Road Asphalt Pavements in an Eco-Friendly Way

The integration of circular economy principles in the design of road pavements raises the problem of obtaining high-performance asphalt mixtures for reduction of waste and environmental pollution compared to traditional solutions. In this study, the base and binder layers of road asphalt pavements were prepared by using reclaimed asphalt pavement and construction and demolition waste as coarse aggregates, while jet grouting waste and fly ash served as fillers. A leaching test was performed for the marginal materials, after which the engineering performances of the designed asphalt mixtures were investigated through laboratory tests. A life cycle assessment methodology was applied to determine the life cycle impacts of one cubic meter of each asphalt solution. Next, a multi-criteria decision analysis (MCDA) was performed for the solutions suggested for the binder and base layers. Finally, a sensitivity analysis was conducted to identify the most suitable MCDA solutions by varying the weights for a total of 24 different weight configurations. The results of this work revealed that the solutions utilizing jet grouting waste (in particular, the hot asphalt mixture for the binder layer and cold asphalt mixture for the base layer) were preferred to other traditional and alternative solutions in most decision-making scenarios.

СRUSHED STONE MATERIALS AND GRAVEL MATERIALS BOUND BY MINERAL BINDERS. STANDARDIZATION

Introduction. This paper presents the results of the standardization of requirements for granular mixtures bound by mineral binders for bases, sub-bases and top layers of road pavements used as framework for national standard «Crushed stone materials and gravel materials for the road building industry — Specifications. Part 3: The materials bound by mineral binders». Standardization. The standard covers the requirements for crushed stone-sand and sand-gravel mixtures treated with mineral binders and derived from them hardened materials as well as the requirements for source constituents. Mineral binder for the standardized type of road materials shall be selected from following main constituents: cement, slag or fly ash each separately or combinations thereof using an activator if required. Standard mixtures shall be produced in a factory or mixed in situ on the road surface. Clauses of the standard also comprise the requirements for mixtures and related hardened materials from active slag or ash-slag materials which can act as the main constituent of the mixture (aggregate) and part of the binder. Standardized mandatory characteristics include mixtures physical properties comprising grading envelopes, and mechanical properties; the obligatory sections of the standard include requirements on quality control, transporting and marking of mixtures. Conclusions. Conclusions outline main results of standardization in view of the ongoing works on processing the related European Norms as national normative documents. It is emphasized that the developed standard supplements the fundamental requirements of adapted European normative documents regarding the composition and properties of said mixtures, particularly the requirements on frost resistance. The subsequent work shall be aimed at the adaptation of national regulations on road pavement design and construction to implement the newly standardized requirements for hydraulically bound mixtures.

Potential Investigation of Stabilised Fuming Furnace Slag for Road Construction

Fuming furnace (FF) slag is one of the industrial waste materials which is generated during extraction of zinc metal at the zinc industry. It is deposited at the designated FF slag yard near the plant area with very limited use. As a result, the deposits are increasing year after year posing threat to the environment and occupying large area of precious land. The present research explores the possibility of using this waste material in the road construction. The tests like Scanning electron microscope (SEM), Energy dispersive spectrometer (EDS) and X-ray diffraction was carried out on FF slag. To improve its geotechnical properties, it was mechanically stabilised with jarofix (another waste material generated from the same zinc industry) in the range of 25 to 75 percent. Apart from compaction characteristics, shear strength and consolidation characteristics of these mixes were studied to conclude about its feasibility in embankment and granular layers of road pavement. These mixes were further chemically stabilized with cement in the range of 3 to 9 percent to investigate their potential application in sub base and base layers of road construction. Compressive and durability characteristics of these mixes were also studied. Detailed laboratory study concluded that FF slag is a porous; amorphous cohesionless coarse grained material with high angle of internal friction. Engineering properties viz. dry density, CBR, and shear strength characteristics improved significantly after mechanical stabilisation with jarofix. These parameters of FF slag were compared with other industrial waste materials. Unconfined compressive strength and durability characteristics indicated suitability of cement stabilised slag-jarofix mixes for sub base and base layers of road pavement. It was concluded that about 20-30 percent of FF slag can be used as a replacement of fine aggregate in these granular layers. A typical pavement design indicated that it is possible to reduce the total pavement thickness of about 13 percent by using cement stabilised slag-jarofix mix.

Reusing Jet Grouting Waste as Filler for Road Asphalt Mixtures of Base Layers.

Secondary raw materials consist of production waste or material resulting from recycling processes, currently in large quantities, which can be injected back into the economic system as new raw materials. This study proposes jet grouting waste (JGW) as filler for hot and cold asphalt mixtures applied as base layers of road pavements and investigates the physical and mechanical properties. JGW is derived from soil consolidation performed during underground roadway tunnel construction. The research compares three asphalt mixtures: (a) hot mixture containing limestone aggregate-filler (HMA), (b) HMA containing JGW (HMAJ), (c) cold recycled asphalt mixture containing JGW (CRAJ). Leaching tests of JGW and reclaimed asphalt pavement (RAP) were conducted; the best configurations of the three mixtures were determined by using the volumetric method through gyratory compaction. Three mastics with filler-to-binder ratios reflecting those of the asphalt mixtures were investigated through delta ring and ball test and frequency sweep test at 0.05% stress by using a dynamic shear rheometer. The morphology of each mixture was further investigated by scanning electron microscopy. The results showed that CRAJ with 28 days of curing time reached the indirect tensile strength (ITS) of HMA (0.73 MPa) within 14 days and, among all studied mixtures, returned the lowest cumulative strain, which was on average 30% lower than that of HMA and HMAJ. The results of this study have shown that the cold alternative mixture, CRAJ, promotes the reuse of two types of waste, RAP and JGW, as it fully meets the reference Italian Technical Standard and ensures good mixture performance in addition to conserving natural resources.

STUDY OF THE INFLUENCE OF GEOTEXTILE MATERIALS DURING CONSTRUCTION OF DAMS

One of the real and promising ways to expand the range and types of structures for strengthening the slopes of embankments and dams is the use of geotextile materials. In the structures under consideration, they can perform protective, filtering, separating, reinforcing functions and moreover they improve the working conditions of the soil and layers of road pavements on the sides of the road and in the slope parts, increasing their stability. The use of geotextiles makes it possible to develop technically and economically effective design solutions. As the analysis of literature data has shown, soil reinforcement is an effective method for increasing the bearing capacity of foundations at a relatively low cost. Therefore, research, both theoretical and experimental, the development and creation of computational models taking into account the influence of reinforcing elements is an urgent problem. The paper considers the stress-strain state of a bulk dam without and with two options for the location of geotextiles. On the basis of the carried out numerical modeling, it is shown how when using geotextiles, the bearing capacity of a structure increases, while the volume of materials decreases. At the second stage, on the basis of the calculations, the optimal variant of the location of the geotextile material in the body of the structure was selected with the best technical and economic indicators. The research results show that when reinforcing the embankment with open clips in two rows – in the upper and lower parts-the smallest horizontal and vertical movements are obtained at almost the same total stresses. At the same time, the required value of the resistance coefficient is achieved, and the volume of soil is reduced. Thus, it can be concluded that the use of geotextile materials can reduce the cost of basic building materials while increasing operational characteristics and extending the service life of the structure.

Effect of Tropical Natural Rubber on the Hot Rolled Sheet (HRS) Wearing Course

One effort to improve the performance of road pavement layers and the quality of asphalt mixes is through the modification of asphalt by polymeric materials addition. Latex is a polymer material that can be used and easily found in Indonesia, known as one of the world’s largest natural rubber producer countries. This study intended to improve the quality of Hot Rolled Sheet Wearing Course (HRS-WC) mixture by utilizing latex 1%, 2%, 3%, 4%, 5%, 6%, 7%, and 8% as a partial replacement of asphalt material through Marshall testing. From the test results, it can be summarized that the Optimum Asphalt Content (OAC) value of the HRS-WC mixture was 7%. Furthermore, the Optimum Latex Content (OLC) meeting the specifications was 1% with a Density value of 2.25, a VMA value of 19.68%, a VFA value of 76.78%, a VIM value of 4.57%, a stability value of 1766.44 kg, a Flow value of 3.14 mm, and MQ value of 629.01 kg/mm

Performance Evaluation of Crushed Glass in Stabilizing Lateritic Soil for Road Pavement Layers

Performance Evaluation of Crushed Glass in Stabilizing Lateritic Soil for Road Pavement Layers

Model for determining the elastic moduli of road pavement layers

Model for determining the elastic moduli of road pavement layers

Multi-scale study of bio-binder mixtures as surface layer: Laboratory evaluation and field application and monitoring

The potential use of bio-binders as full or partial substitutes of petroleum-based binders have gained interest from the paving researches in recent years. Although there are many studies about rheological characterization of alternative binders, there is still lack of knowledge about mixtures and field performance of this type of materials. In this sense, this paper presents an evaluation of bio-binder produced from vegetal biomass, by-product of the treatment of pine wood resin, as the total substitute of the asphalt binder for surface pavement layer, comparing its performance with a neat asphalt binder, used as reference, at three study levels: binder evaluation, mixture evaluation and field performance monitoring. Linear viscoelastic characterization, permanent deformation and fatigue responses were studied for the binders. The mixtures designed with both binders were tested in terms of stiffness, moisture sensitivity and permanent deformation. The performance in the field test sections was monitored during three years by structural evaluation (FWD) and roughness test (IRI). Results showed that the bio-binder studied presented acceptable behavior, with similar responses of that exhibited by the petroleum-based asphalt binder. The bio-binder studied could be used as binder in mixtures for surface layers of road pavements, however, the durability of that type of mixtures and the environmental impact of the production process need to be further studied in order to complement the feasibility of this alternative as a sustainable solution.