Search Results (21)

Compacted and degraded soils pose increasing challenges to agricultural practices, necessitating innovative approaches to soil tillage. This paper evaluates the performance of a vibratory-enhanced moldboard plowing system, designed to improve energy efficiency and tillage quality under compacted and moisture-deficient conditions, typical of low-moisture soils. Field experiments were conducted across four distinct Romanian regions with varying soil types and climatic conditions, all characterized by significant compaction and limited soil moisture. The vibratory system, mounted directly on each plow body, employed sinusoidal oscillations generated by a DC moto-vibrator, to reduce soil adhesion and traction force requirements, thereby lowering fuel consumption. Key parameters including fuel consumption, working speed, soil fragmentation, weed incorporation, and traction force were measured and compared with the conventional plowing method. The results showed enhanced soil fragmentation and more effective residue incorporation, along with notable reductions in traction effort and fuel use at optimal oscillation settings. These findings highlight the potential of vibratory tillage to be used as a soil preparation method for compaction-prone areas, improving the soil structure while increasing operational energy efficiency. Full article

Smart construction technology integrates artificial intelligence, Internet of Things, UAVs, and building information modeling to improve productivity and quality in construction. In road embankment earthworks, ground compaction quality is critical for structural stability and maintenance. This study proposes a methodology combining UAV photogrammetry with intelligent compaction quality management systems to evaluate surface flatness and compaction homogeneity in real-time. High-resolution UAV images were used to generate digital elevation models, from which surface roughness was extracted using terrain element analysis and fast Fourier transform. Local terrain changes were interpreted through contour gradient, outline gradient, and tangential gradient curvature analysis. Field tests were conducted at a pilot site using a vibratory roller, followed by four compaction quality assessments: plate load test, dynamic cone penetration test, light falling weight deflectometer, and compaction meter value. UAV-based flatness analysis revealed that, when surface flatness met the standard, a strong correlation was observed, with results from conventional field tests and intelligent compaction data. The proposed method effectively identified poorly compacted zones and spatial inhomogeneity without interrupting construction. These findings demonstrate that UAV-based terrain analysis can serve as a nondestructive real-time monitoring tool and contribute to automated quality control in smart construction environments. Full article

The present study investigates the effects of different compaction methods on the properties of roller-compacted concrete (RCC) used for road pavements. The study focuses on comparing the Proctor compaction method utilizing different compaction efforts and molds (2.5 kg rammer with three layers of 56 blows and 4.5 kg with three and five layers of 56 blows, cylindrical and cube molds) with a slab compactor in static and vibratory setting. The samples produced in a slab compactor were obtained by drilling from the prepared slab. The evaluated properties of the samples included compressive strength and bulk density. The study involved a C25/30 concrete with the intention to be used in low volume roads according to national standards. The study concluded that the utilization of Proctor compaction and slab compactor with vibratory setting provided similar levels of strength performance of the RCC mixture, regardless of the shape of the Proctor compacted samples. In terms of the bulk densities, the main differentiating factor in the case of Proctor compaction was the weight of the rammer. The compressive strength of the samples was also strongly related to their bulk densities. Full article

The compaction of asphalt pavement is a crucial step to ensure its service life. Although intelligent compaction technology can monitor compaction quality in real time, its application to individual asphalt surface courses still faces limitations. Therefore, it is necessary to study the compaction mechanism of asphalt pavements from the particle level to optimize intelligent compaction technology. This study constructed an asphalt pavement compaction model using the Discrete Element Method (DEM). First, the changes in pavement smoothness during the compaction process were analyzed. Second, the changes in the angular velocity of the mixture and the triaxial angular velocity (TAV) of the mortar, aggregates, and mixture during vibratory compaction were examined. Finally, the correlations between the TAV amplitude and the coordination number (CN) amplitude with the compaction degree of the mixture were investigated. This study found that vibratory compaction can significantly reduce asymmetric wave deformation, improving pavement smoothness. The mixture primarily rotates in the vertical plane during the first six passes of vibratory compaction and within the horizontal plane during the seventh pass. Additionally, TAV reveals the three-dimensional dynamic rotation characteristics of the particles, and the linear relationship between its amplitude and the pavement compaction degree aids in controlling the compaction quality of asphalt pavements. Finally, the linear relationship between CN amplitude and pavement compaction degree can predict the stability of the aggregate structure. This study significantly enhances quality control in pavement compaction and advances intelligent compaction technology development. Full article

Full-depth reclamation with Portland cement (FDR-PC) represents an innovative cold recycling technology for pavements, holding significant promise due to its capacity to reuse deteriorated pavement base layers. This paper investigates the key factors influencing the strength properties of FDR-PC. The results indicate that, compared to the static compaction method, the vibratory compaction method yields cold-recycled mixtures with higher maximum dry density and unconfined compressive strength (UCS). Increasing the cement content and base-to-surface ratio, extending the curing time, and raising the curing temperature all contribute to enhancing UCS. Furthermore, increasing the base-to-surface ratio and cement content enhances both indirect tensile strength and flexural strength. An approximate linear correlation exists between indirect tensile strength and UCS, as well as between flexural strength and UCS. The strength characteristics of FDR-PC were comprehensively characterized in this study, providing effective verification of its applicability. Full article

To address the uncertainty of optimal vibratory frequency f_ov of high-speed railway graded gravel (HRGG) and achieve high-precision prediction of the f_ov, the following research was conducted. Firstly, commencing with vibratory compaction experiments and the hammering modal analysis method, the resonance frequency f₀ of HRGG fillers, varying in compactness K, was initially determined. The correlation between f₀ and f_ov was revealed through vibratory compaction experiments conducted at different vibratory frequencies. This correlation was established based on the compaction physical–mechanical properties of HRGG fillers, encompassing maximum dry density ρd_max, stiffness K_rd, and bearing capacity coefficient K₂₀. Secondly, the gray relational analysis algorithm was used to determine the key feature influencing the f_ov based on the quantified relationship between the filler feature and f_ov. Finally, the key features influencing the f_ov were used as input parameters to establish the artificial neural network prediction model (ANN-PM) for f_ov. The predictive performance of ANN-PM was evaluated from the ablation study, prediction accuracy, and prediction error. The results showed that the ρ_dmax, K_rd, and K₂₀ all obtained optimal states when f_ov was set as f₀ for different gradation HRGG fillers. Furthermore, it was found that the key features influencing the f_ov were determined to be the maximum particle diameter d_max, gradation parameters b and m, flat and elongated particles in coarse aggregate Q_e, and the Los Angeles abrasion of coarse aggregate LAA. Among them, the influence of d_max on the ANN-PM predictive performance was the most significant. On the training and testing sets, the goodness-of-fit R² of ANN-PM all exceeded 0.95, and the prediction errors were small, which indicated that the accuracy of ANN-PM predictions was relatively high. In addition, it was clear that the ANN-PM exhibited excellent robust performance. The research results provide a novel method for determining the f_ov of subgrade fillers and provide theoretical guidance for the intelligent construction of high-speed railway subgrades. Full article

Various designs of furnaces for melting alloys are used in the foundry industry. Regardless of their design, they have one common detail, which is the lining of their interiors with refractory materials. This component in the design of a metal-melting furnace has a very important task—to protect the rest of the furnace assemblies from thermal and mechanical damage. Continuous technical progress and the quality requirements of casting production produce increasingly higher demands for refractory materials in connection with their development as well. The article presents the results of an innovative method of vibratory compaction of refractory material (high-alumina aluminosilicate) using reduced pressure. The analysis presents a comparative study of two methods used for forming refractory materials, i.e., the application of the mentioned innovative method and the classical (standard) method of compaction by vibration only. The effects of the introduced modification in the manufacture of ceramic shapes were evaluated by means of the material’s resistance to thermal shock, linear expansion, and dimensional change due to firing, apparent density, open porosity, and apparent specific gravity, determination of total pore volume and pore size distribution by mercury porosimetry, and slag resistance. The tests performed indicate that the procedure of lowering the pressure during the vibratory compaction of the refractory material creates a more homogeneous structure with a smaller number and size of pores. This makes it possible to improve most of the parameters that determine the quality of the refractories used for the linings of the foundry furnace. Full article

This paper presents results obtained for the vibratory compaction process of road structures, in which the natural soil is used for the foundation infrastructure. The experiments and the optimization of the compaction process were carried out on five road lanes in Transilvania, Romania. A self-propelled single-drum roller compactor, BOMAG BW 213 S-5, was used for the compaction, layer by layer, with six successive passes over each layer. For each layer, the initial degree of compaction was measured, and after the fifth pass, it achieved the value prescribed in the road construction project. After each pass over the same layer, its settlement increased due to the plastic deformation and the soil’s rigidity receiving discrete higher values. This is how five different discrete values for rigidity were obtained. Modeling the compaction process is carried out using the Kelvin–Voigt model, with discrete variable experimental values for soil rigidity and assumed constant viscous damping values. Based on the two-degree-of-freedom linear elastic model, graphs were plotted for vibration amplitude variation and for the force transmitted to the soil when the excitation pulsation varies continuously and the soil rigidity varies discretely. There is a relationship between the initial and final degree of compaction values in the ratio that was proven to be dependent on the ratio of amplitude values corresponding to the final and initial roller passes cycle. The result is a useful relationship for the “in-situ” estimation of the compaction process effect. The novelty of this research is that it demonstrates the change in soil rigidity values after each pass of the vibratory roller and, thus, the increase of its settlement (plastic deformation) and the “slipping” for the amplitude resonance peak by discrete increasing values. Calibration of the resonance vibrations regime in accordance with the degree of compaction determined by geotechnical methods for “in-situ” sample prelevation stands as a fast and efficient method for the evaluation of the final degree of compaction value. This is, implicitly, the method for estimating the number of vibratory roller passes in the road construction project. In conclusion, the novelty of the research consists in the fact that, through using the resonance response of the vibratory roller, a correlation was made with the degree of compaction achieved after each pass. Full article

The accumulation of discarded tire rubber poses significant challenges in terms of land usage and environmental hazards. To address this issue, this article explores the potential reuse of rubber in roadbed engineering. This study conducts a comprehensive examination of the vibration compaction process involving a vibratory roller and rubber–sand mixtures, utilizing the discrete element method (DEM) in a two-dimensional (2D) framework to investigate the impact of dynamic vibration compaction on sand mixtures with varying rubber contents under different roller working conditions, while also evaluating the associated energy consumption. The results reveal that both the rubber content and operational parameters of the roller significantly influence compaction vibration effects. Notably, optimal rolling frequency, velocity, and rolling mass show correlations with the rubber content. Furthermore, this research provides a microscopic understanding of the compaction process, offering detailed insights into displacement fields, velocity fields, and contact forces. Full article

In order to solve the equilibrium problem related to compaction degree, structural integrity of skid resistance, and skid resistance of asphalt wearing layer on a concrete bridge deck, the influence of rolling mode on compaction degree, structural integrity of skid resistance, and skid resistance performance was analyzed according to compaction curve characteristics, image processing technology, and laser method from the compaction mechanism and temperature control of rolling equipment. The results showed that the compaction degree and rolling times of an SMA-13 asphalt wearing course on the bridge deck could be characterized by a logarithmic model, and the model parameters had clear physical significance. Compared with the vibratory roller, the oscillation roller could achieve a greater and more stable compaction degree of the mixture and maintain a better density, compaction degree, and void ratio after 5 times of oscillation rolling. The pavement wear characteristics were extracted by a digital image method. The results showed that with the increase in rolling times, the rolling temperature decreased gradually, and the wear rate of surface texture increased significantly. The multiscale evaluation of pavement antiskid performance by a laser method showed that the surface structure gradually decreased and tended to be stable (1.2 mm) with the increase in rolling times of the vibratory roller, the microscopic texture density increased with the increase in rolling times, and the proportion of acute angle (<90°) in the peak angle of the surface texture profile decreased with the increase in rolling times. The SMA-13 asphalt wearing course on the bridge deck was rolled by a vibratory roller for 6 times, so as to achieve the balance of compaction degree, structural integrity, and skid resistance. Full article

Due to their advantages of compact size, high reduction ratio, large stiffness and high load capacity, RV reducers have been widely used in industrial robots. The dynamic characteristics of RV reducers in terms of vibratory response and dynamic transmission error have a significant influence on positioning accuracy and service life. However, the current dynamic studies on RV reducers are not extensive and require deeper study. To bridge this gap, a more effective and realistic lumped parameter dynamic model for RV reducers is developed, considering the tooth profile modification of cycloid gears and system errors. Firstly, for an efficient solution, the equivalent pressure angle and equivalent mesh stiffness of the cycloid–pin gear pair are introduced in the dynamic model based on the loaded tooth contact analysis. Secondly, the differential equations of the system are derived by analyzing the relative displacement relationships between each component, which are solved using the Runge–Kutta method. With this, the effects of errors such as machining errors, assembly errors and bearing clearances on the dynamic behaviors and transmission precision are investigated by comparison to quantify or qualify their influence. This research is helpful in characterizing the multi-tooth mesh and dynamic behavior, and revealing the underlying physics of the RV reducer. Full article

The ASTM D6951 suggests a test method using the dynamic cone penetrometer (DCP) for the assessment of shallow pavement strength. This study is dedicated to evaluating a similar test method to be used for fine-grained clay–sand mixtures, which are commonly used to construct liners and fluid barriers. The liner layers include clay, which is water-sensitive. The shear strength of the liners depends mainly on the composition and proportions of the mixtures adopted. A series of tests were conducted in the laboratory for compacted clay–sand mixtures, including 5% and 10% bentonite material. The responses to advancing a dynamic probe into compacted material at three various moisture conditions—namely, the optimum, dry of optimum, and wet of optimum water contents—are investigated. The penetration profiles are compared for the two clay content levels selected and for three moisture state conditions. The clay–sand liners support vehicles and vibratory compactors during construction and when waste material is placed. The shear strengths of the mixtures are evaluated in the laboratory using direct shear tests. From the results obtained in this investigation, general guidelines and recommendations are presented to help with the efficient assessment of liners consisting of clay–sand mixtures. A cheap and quick approach to assess the density and shear strength of landfill liners or clay–sand layers can be achieved using a hand-held dynamic cone penetrometer. The state of moisture during compaction was found to influence the DCP results. The compaction of layers in a wet of optimum state is not expected to be an ideal alternative. Full article

The tunneling rock wastes (TRW) have been increasingly generated and stockpiled in massive quantities. Recycling them for use as unbound granular pavement base/subbase materials has become an alternative featuring low carbon emission and sustainability. However, the field compaction of such large-size, open-graded materials remains challenging, thus affecting post-construction deformation and long-term stability of such pavement base/subbase layers. This study conducted a series of proctor compaction and new plate vibratory compaction tests to analyze the compaction characteristics of such TRW materials. A total of six different open gradations were designed from particle packing theory. In addition, the effects of gradation and compaction methods on the compaction characteristics, particle breakage of TRW materials, and the optimal combination of vibratory parameters were investigated by normalizing the curves of achieved dry density versus degree of saturation for various combinations of gradations, compaction methods, and compaction energy levels. The post-compaction characteristics of interparticle contact, pore structure, and particle breakage were analyzed from the X-ray computed topography (XCT) scanning results of TRW specimens with different gradations. The findings showed that the gravel-to-sand ratio (G/S) based gradation design method can effectively differentiate distinct types of particle packing structures. There exists an optimal G/S range that could potentially result in the highest maximum dry density, the lowest particle breakage, and the best pore structure of compacted unbound permeable aggregate base (UPAB) materials. The achieved dry density (ρ_d) of UPAB materials subjected to vibratory plate compaction exhibited three distinct phases with compaction time, from which the optimal excitation frequency range was found to be 25–27 Hz and the optimal combination of vibratory parameters were determined. The normalized compaction curves of degree of saturation versus achieved dry density were found insensitive to changes in material gradations, compaction methods and energy levels, thus allowing for a more accurate evaluation and control of field compaction quality. Full article

In recent years, an intelligent vibratory roller with adjustable mode has become the leading direction for the development of compaction equipment that can obtain the state of the pressed material during the compaction operation and then control the working parameters and the excitation mode of the whole machine according to the condition of the pressed material. The intelligent vibratory roller can better meet today’s requirements for compaction. This paper proposes a compaction operation monitoring system for an intelligent vibratory roller based on the Internet of Things. Firstly, a hardware system for real-time compaction operation monitoring was established, including the selection of a sensor module and signal conditioning module. Secondly, a method for real-time compaction monitoring data evaluation and analysis of compaction was proposed and a detailed analysis process of the compaction data was designed. Finally, the compaction operation monitoring prototype system based on the Internet of Things technology was designed and constructed. Full article

Electrostatic voltage is a vital parameter in industrial production lines, for reducing electrostatic discharge harms and improving yields. Due to such drawbacks as package shielding and low resolution, previously reported electric field microsensors are still not applicable for industrial static monitoring uses. In this paper, we introduce a newly designed microsensor package structure, which enhances the field strength inside the package cavity remarkably. This magnification effect was studied and optimized by both theoretical calculation and ANSYS simulation. By means of the digital synthesizer and digital coherent demodulation method, the compact signal processing circuit for the packaged microsensor was also developed. The meter prototype was calibrated above a charged metal plate, and the electric field resolution was 5 V/m, while the measuring error was less than 3 V, from −1 kV to 1 kV in a 2 cm distance. The meter was also installed into a production line and showed good consistency with, and better resolution than, a traditional vibratory capacitance sensor. Full article