USE OF ACRYLIC COPOLYMER ADDITIVE SOIL STABILIZATION PLUS FOR PREPARATION OF MIXTURES MADE BY COLD RESYCLING TECHNOLOGY AND CRUSHED STONE-SAND MIXTURES IN PAVEMENT FOUNDATION LAYERS

ntroduction. Rehabilitation of public roads network requires a comprehensive recovery with strengthening of the bearing capacity of the pavement foundation. Rehabilitation of the foundation bearing capacity performed by arranging layers of road material made by cold recycling technology (hereinafter — CRRM) in accordance with [4] or by arranging a layer of crushed stone — sand mixture reinforced with cement or complex binder (hereinafter — CSSM 20) according to [13]. Purpose. The purpose of the work is to study the feasibility of using acrylic additives for the preparation of mixtures made by cold recycling technology and crushed stone-sand mixtures treated with cement in the layers of pavement foundation. Materials and methods. Experimental comparative tests of CRRM and CSSM 20 with different content of complex binder were performed. Results. Feasibility of acrylic additives use has been established (hereinafter — the additive) for the preparation of CRRM and CSSM 20 in the pavement foundation layers. Recommendations on technological parameters of preparation, transportation, laying and compaction of mentioned mixtures are given. Conclusions. Performed researches have shown that according to physical and mechanical indicators CRRM and CSSM20 meet the requirements of the current normative documents of Ukraine. The advantages of use are noted.

Optimum Pavement Thickness for Rigid Pavement in UP Eastern Region

Highways are important in the growth of the economy of the nation. Pavement distributes and reduces the loads to the subgrade so as not to destruct the pavement foundation and subgrade. Thermal stresses are more vulnerable and to be included as the ability to contract and expand concrete is very less. The roads provide vehicle access to various points in all weather conditions and provide road users with a clean, smooth, and comfortable ride without unnecessary delay or excessive wear and tear. Since the UP eastern region faces tremendous temperature differences, load variations, and moisture conditions. This paper puts an attempt to identify the optimum thickness of the rigid pavement to sustain these extreme temperature variations, high humidity, and various load configurations. In this paper the various configurations of the loads are taken from the IRC 6: 2016 along with the various moisture and temperature data are taken from the Indian Meteorological Department (IMD) ministry of Earth and Science government of India. The paper gives a brief idea of pavement thickness selection. This paper utilizes Finite Element Method (FEM) based Software’s KENPAVE along with ANSYS 12.1 for a better understanding of the critical stress and its positions where the pavement needs attention in the design. All these varying conditions are incorporated in these software’s and the results obtained were in the form of figures, graphs, and deflected shapes. Parametric variation in the pavement section (i.e. variation in thickness of PQC, DLC layer, and in Modulus of Elasticity), variation in poisons ratio and temperature by using these results and doing cost analysis the optimum pavement thickness was obtained.

Classification of Variable Foundation Properties Based on Vehicle–Pavement–Foundation Interaction Dynamics

The dynamic interaction between vehicle, roughness, and foundation is a fundamental problem in road management and also a complex problem, with their coupled and nonlinear behavior. Thus, in this study, the vehicle–pavement–foundation interaction model was formulated to incorporate the mass inertia of the vehicle, stochastic roughness, and non-uniform and deformable foundation. Herein, a quarter-car model was considered, a filtered white noise model was formulated to represent the road roughness, and a two-layered foundation was employed to simulate the road structure. To represent the non-uniform foundation, stiffness and damping coefficients were assumed to vary either in a linear or in a quadratic manner. Subsequently, an augmented state-space representation was formulated for the entire system. The time-varying equation governing the covariance of the response was solved to examine the vehicle response, subject to various foundation properties. Finally, a linear discriminant analysis method was employed for classifying the foundation types. The performance of the classifier was validated by test sets, which contained 100 cases for each foundation type. The results showed an accuracy of over 90%, indicating that the machine learning-based classification of the foundation had the potential of using vehicle responses in road managements.

Effect of Modulus of Bituminous Layers and Utilization of Capping Layer on Weak Pavement Subgrades

The majority of the world’s highways consist of a flexible pavement commonly built of several layers (both asphaltic and granular) that have been laid over a pavement foundation known as the subgrade. A subgrade that is considered to be of a satisfying bearing capacity is expected to restrict not only the immediate distresses occurring during the construction phases, but also later deformations appearing during the service life of the pavement as it subjected to traffic loads. If the subgrade proves to be structurally weak, the highway’s flexible pavement can be supported by adding such modifications as a capping layer, which serves to greatly reduce the stress being applied to the pavement. This study aims to further our knowledge about maximum pavement functionality by investigating those parameters considered crucial to pavement design: the correspondence of material properties, the number of layers, and the layer thickness. These parameters were analyzed to determine the best performing composition, while also considering the financial aspects of road construction. To achieve such an aim, we chose to use KENLAYER software to assist us in determining the design of a flexible pavement in line with a specific Equivalent Single Axle Load (ESAL). The KENLAYER configuration provided us with the required ESAL targets for specific design lives. We next calculated the relative costs of these targets and chose those that proved to be most cost-effective and economical. The results indicate that when considering feasible pavements to meet a design of high ESAL applications, those utilizing high modulus asphaltic materials are most suitable for subgrade CBR of at least 3%, while weaker subgrade constructions must be provided with a capping layer.

Stiffness and Strength Improvement of Geosynthetic-Reinforced Pavement Foundation Using Large-Scale Wheel Test

Laboratory cyclic plate load tests are commonly used in the assessment of geosynthetic performance in pavement applications due to the repeatability of testing results and the smaller required testing areas than traditional Accelerated Pavement Testing facilities. While the objective of traditional plate load testing procedure is to closely replicate traffic conditions, the reality is that rolling wheel loads produce different stresses in pavement layers than traditional cyclic plate load tests. This two-fold study investigates the differences between the stress response of subgrade soil from a rolling wheel load (replicating rolling traffic conditions) and a unidirectional dynamic load (replicating traditional plate load test procedures) in order to obtain a more realistic stress response of pavement layers from rolling wheel traffic. Ultimately, results show that the testing specimens that experienced rolling wheel loading had an average of 17% higher pressure measurements in the top of the subgrade than vertically loaded (unidirectional dynamic load) specimens. The second segment of this study is used in conjunction with the first to analyze aggregate base material behavior when using a geosynthetic for reinforcement. The study aimed to determine the difference in the post-trafficked strength and stiffness of pavement foundation. A Dynamic Cone Penetrometer and Light Weight Deflectometer were utilized to determine material changes from this trafficking and revealed that all specimens that included a geosynthetic had a higher base stiffness and strength while the specimen with geotextile and geogrid in combination created the highest stiffness and strength after large-scale rolling wheel trafficking.