Gravel Material Research Articles

Characterization of gravel borrow pits materials for construction of low volume roads in Dodoma Tanzania

The study was conducted to investigate suitability of gravel materials from borrow pits which are used for low volume roads construction in Dodoma region Tanzania. Characterization of four borrow pits gravel materials from Dinda, Mahomanyika, Nkulabi and Ntyuka were conducted. Blending process of the borrow pits materials with sand from Ihumwa and clay from Michese in order to improve missed engineering properties were conducted. The GC, SP and PI were 25.4 units, 391.3 units and 16% for Dinda, 32.3 units, 56.0 units and 10% for Mahomanyika, 33.7 units, 148.1 units and 14% for Nkulabi and 32.8 units, 111.2 units and 13% for Ntyuka borrow pit materials respectively. Results of CBR for source materials were 14%, 16%, 29%, and 30% for Dinda, Nkulabi, Mahomanyika, Ntyuka borrow pits materials respectively. The results indicated that all source gravel materials did not comply with requirements as gravel materials for low volume roads. This is because Mahomanyika borrow pit materials has low SP values which required blending with clay materials and Dinda, Nkulabi and Ntyuka have high PI values which required blending with sand. Results of GC, SP and PI for the blended materials were 20.1 units, 259.9 units and 12% for 75Dind25San, 31.3 units, 126.7 units and 11.9% for 85Mah15Cla, 31.0 units, 120.0 units and 11.2% for 80Nku20San and 30.3 units, 104.2 units and 10.4% for 80Nty20San respectively. CBR values of blended materials were 19%, 32%, 16% and 26%, for 75Din25San, 85Mah15Cla, 80Nku20San and 80Nty20San respectively. It has been investigated that all blended materials are suitable for construction of low volume roads in Dodoma region since they have satisfied GC, SP, PI and CBR requirements as surfacing materials for construction of low volume roads. It is important to characterized source materials before use in order to investigate engineering properties. In case source materials lack some engineering properties it is necessary to blend with other materials in order to improve missing engineering properties before use. Keywords: Gravel Materials, Low Volume Roads, Characterization, CBR, Blending.

Effect of Silt Content on Mechanical Behavior of River Gravel Material

Effect of Silt Content on Mechanical Behavior of River Gravel Material

Experimental Study on Key Techniques for the Construction of High Asphalt Concrete Core Rockfill Dam under Unfavorable Geological Conditions

Asphalt concrete core dams (ACCDs) have been widely constructed in Xinjiang, yet the design of materials and structures has mainly relied on empirical knowledge without substantial theoretical grounding. In this study, we carried out a large-scale relative density test of gravel material in Bamudun dam, studied the compaction characteristics of gravel material, and determined the relative density characteristic index, in order to provide a basis for the subsequent dam material rolling test and construction quality inspection. Furthermore, in order to improve the efficiency of dam construction in narrow valleys, we optimized the connection type between asphalt concrete core wall and bedrock, and proposed a rapid construction method of paving core wall after pouring mass concrete base on bedrock. Finally, we established a three-dimensional finite element model to systematically analyze the stress and deformation patterns of the dam body, core wall, and base of the ACCD at Bamudun. The results show that the maximum compressive stress suffered by the core wall during the full storage period is 1.62 MPa, there is no tensile stress, and the risk of hydraulic splitting is small. The stress and deformation levels of each part are within the safe range. This verifies the rationality of the rapid construction method. The research findings can provide a great theoretical significance and engineering value for the safe design and construction of ACCDs.

A New Method for Constructing the Protection and Seepage Control Layer for CSGR Dam and Its Application

Effective seepage control is crucial for maintaining the structural integrity of Cemented Sand, Gravel and Rock (CSGR) dams. Traditional methods using conventional concrete (CVC) or grout-enriched roller-compacted concrete (GERCC) are costly and disruptive. This paper presents a novel technique for constructing the protection and seepage control layer in Cemented Sand, Gravel and Rock (CSGR) dams. The method involves grouting and vibrating the loosened Cemented Sand, Gravel and Rock (CSGR) material to create vibrated grout-enriched Cemented Sand, Gravel and Rock, which performs similarly to concrete. A new surface water stop structure has also been developed for the structural joints. Laboratory tests revealed that Cemented Sand, Gravel and Rock (CSGR) with a vibrating–compacted (VC) value of 2–6 s and a compressive strength of 4 MPa meets design requirements for medium and low dams when the slurry addition rate is 8–12%. The T-shaped surface water stop demonstrated a bonding strength of over 1.8 MPa, withstanding a water pressure of 1.6 MPa. This method, integrated with dam body construction, reduces material costs by about 50% and eliminates construction interference. Specialized equipment for this technique has been developed, with a capacity of 12 m2/h. Implemented in the Minjiang Navigation and Hydropower Qianwei Project and Shaping I Hydropower Station, it has shown significant economic, environmental and safety benefits, promoting sustainable dam construction.

Enhancing pollutant removal efficiency in urban domestic wastewater treatment through the hybrid multi-soil-layering (MSL) system: A case study in Morocco.

This paper evaluates the performance and potential of a full-scale hybrid multi-soil-layering (MSL) system for the treatment of domestic wastewater for landscape irrigation reuse. The system integrates a solar septic tank and sequential vertical flow MSL and horizontal flow MSL components with alternating layers of gravel and soil-based material. It operates at a hydraulic loading rate of 250 L/m2/day. Results show significant removal of pollutants and pathogens, including total suspended solids (TSS) (97%), chemical oxygen demand (COD) (88.57%), total phosphorus (TP) (79.93%), and total nitrogen (TN) (88.49%), along with significant reductions in fecal bacteria indicators (4.21 log for fecal coliforms and 3.90 log for fecal streptococci) and the pathogen Staphylococcus sp. (2.43 log). The principal component analysis confirms the effectiveness of the system in reducing the concentrations of NH4, COD, TP, PO4, fecal coliforms, fecal streptococci, and fecal staphylococci, thus supporting the reliability of the study. This work highlights the promising potential of the hybrid MSL technology for the treatment of domestic wastewater, especially in arid regions such as North Africa and the Middle East, to support efforts to protect the environment and facilitate the reuse of wastewater for landscape irrigation and agriculture.

Deterioration Index Analysis of Cemented Sand and Gravel Materials under Freeze–Thaw Action

Deterioration Index Analysis of Cemented Sand and Gravel Materials under Freeze–Thaw Action

Discrete Element Simulation of Macro and Micro Mechanical Properties of Round Gravel Material under Triaxial Stress

In this study, the effects of relative density and confining pressure on the shear characteristics of round gravel are investigated using a large-scale triaxial apparatus and the discrete element method. A simple and efficient numerical method for simulating flexible membranes is introduced. The results show that the stress-strain curves develop from hardened to softened type with increasing relative density, while the stress-strain curves develop from softened to hardened type with increasing confining pressure. As the axial strain increases, the strong contact force chains are vertically distributed, and the larger the relative density and confining pressure, the greater the number and thickness of the strong contact force chains. In the shear process, the distribution of average normal and tangential contact forces show “peanut-shaped” and “petal-shaped”, respectively. The increase in relative density increases the anisotropy of the specimen, while the increase in confining pressure results in a decrease. A linear relationship exists between the macroscopic stress ratio and the anisotropy coefficient. The anisotropy coefficient of the normal contact force provides the greatest contribution to the macroscopic shear strength (about 55%), followed by the anisotropy coefficient of the contact normal (about 26%) and that of the tangential contact force (about 19%).

Effects of Loading and Compaction Conditions on Permanent Strains of Unbound Lateritic Soils from Senegal and Burkina Faso

Permanent strains of granular materials result from the repetitive passage of heavy trucks on the pavement. Pavement design relies mainly on permanent strains to predict rut depths. In order to contribute to the improvement of technical documents used for the design and modelling of pavements in tropical African countries, the researchers have focused on the determination of the permanent deformation parameters of laterites (axial (εp,1) and radial (εp,3) permanent strains). The Repeated Triaxial cyclic Loading (RTL) apparatus was used according to the European standard (EN 13286-7: 2004, Multistage method). Four sites of gravelly lateritic soils chosen, two from Burkina Faso (Badnogo2 and Dédougou) and two from Senegal (Sindia and Lam-Lam) were tested in this research. They are compacted to 95% and more of the optimum with a variation in water content of ±2% of the optimum. The permanents deformations are influenced by the water content, the compaction rate and the stress level. The axial permanent deformation ε1,p (max) decreases by 83.4% when the water content decreases from 12.10% to 7.59%. Moreover with a compactness rate that varies from 95.58% to 100.06%, respectively from a water content that varies from 10.04% to 9.36%, we observe a decrease in deformation ε_(1,p) from 224.340*10-4 to 148.150*10-4 from the 50,000 cycles, which shows the effect of the compactness rate and the stress level on the lateritic gravels materials soils. however, for a good control of permanent deformations on flexible pavements using gravel materials, it is necessary to compact at water contents lower than the optimum added to average compaction rates. Keywords: permanent strains (p), lateritic soils, Repeated Triaxial cyclic Loading (RTL), Sindia, Badnogo2, Dedougou, Lam-lam.

GEOTECHNICAL INVESTIGATION OF ROAD FAILURE ALONG ABUJA- LOKOJA ROAD

A comprehensive investigation of soil properties along the Abuja-Lokoja Road, focusing on samples A and B located between KM51 + 300 to KM51 + 200 and KM45+100 to M51+000 respectively utilizing site analysis, laboratory testing, and comparative analysis, the study identifies critical distinctions in soil composition and engineering behaviours. Sample A, classified as CH (clay of high plasticity), exhibits a moisture content of 12.6% and a density of 1.940 g/cc in contrast, Sample B, classified as GM (gravelly material), has a higher moisture content of 13.8% and a denser structure at 2.100g/cc. Despite differing compositions, both samples demonstrate comparable load-bearing capacities, reflected in California Bearing Ratio (CBR) values at 100% moisture content. Sample A records 32.7% (unsoaked) and 24.6% (soaked), while Sample B exhibits 32.7% (unsoaked) and 26.2% (soaked), indicating similar strength under specific moisture conditions. Further analysis reveals a slightly higher Liquid Limit (LL) for Sample A at 41% compared to Sample B's 40%, with closely aligned Plasticity Index (PI) values, suggesting comparable plasticity characteristics. These findings align with established trends in cohesive and gravelly soils from past research. Recognizing these distinctions is crucial for informed construction practices. The study recommends tailored engineering strategies, based on precise soil characterization, to optimize infrastructure performance and longevity in diverse soil environments. The emphasis on soil analysis and tailored engineering approaches underscores their significance in enhancing infrastructure stability and durability across varying soil conditions.

Mechanical properties of reinforced loess soils in road pavements

The modern development of road construction promotes the tasks of not only increasing the strength of road structures, but also the need to effectively use local materials and soils in road construction. During the design and construction of highways, many road scientists of the world have carried out their scientific and research work on soil strengthening based on the road bed. Several methods and techniques have been developed for this. Also, developed countries are producing a lot of surfactants, modifiers and additives for soil strengthening. In this article, research work was carried out in laboratory conditions to study the mechanical properties of soil strengthened with the help of a modifier. Measurement, comparison, experimental laboratory, mathematical statistical analysis in the processing of test results, analytical methods specified in regulatory documents were used in the performance of research work. The results of the conducted laboratory research are specific to loess soils found in the conditions of Uzbekistan. The use of construction work on the foundation of the road bed from reinforced soil allows to reduce the volume of construction work, reduces the consumption of transported sand and gravel materials, and increases the service life of the road.

Assessment of Surface Layer Characteristic on Flexible Pavement Design Life

The surface, a layer directly under tire load, is often made of crushed aggregate, gravel, or recycled materials. In order to extend the operational lifetime of the road, the surface serves as higher properties of materials. The impact of performance for the surface layer on the design life was examined in this research. Employing the KENPAVE software, the study examined the impact of changing the thickness of the surface layer (2″, 2.5″, and 3″) and the resilient modulus (300, 400, and 500 ksi) on the expected service life of the flexible pavement for both repeated loads 30000 and 40000. The results show that the increased surface layer thickness lead to the increase in pavement design life for all resilient modulus and both repeated loads. The percentage of increase of design life of pavement grew as the resilient modulus grew (for all repeated loads). As resilient modulus of surface layer increased, so did the pavement design life increase. The percentage of increasing the design life of pavement results from increased resilient modulus was increased with the increasing thickness layer. The percentage of improvement the design life of pavement caused by increase of resilient modulus, increase with increase the surface layer thickness (for all repeated loads).

Characterization and Geotechnical Classification of Soils and Lateritic Gravelly Materials along the Songololo-Lufu Road Axis (Kongo Central Province, DR Congo)

Characterization and Geotechnical Classification of Soils and Lateritic Gravelly Materials along the Songololo-Lufu Road Axis (Kongo Central Province, DR Congo)

Optimization of Effective Working Hours for Coal Transportation from Rom to Port: Study at Pt. Maruwai Coal Central Kalimantan

Adaro Mineral Indonesia is one of the pillars of Adaro's mining business which focuses on coking coal mining in Central Kalimantan, planning to increase its coal production. The aim of this research is to optimize effective working hours for transporting coal from ROM to the port. This is done to increase the low productivity of coal transportation activities from mines to ports, which will bring benefits in the form of increased operational efficiency. This research was conducted quantitatively. The data used is primary data and secondary data. Primary data in this research was obtained from direct observations in the coal transportation area from the ROM of coal products to port, which includes cycle time, rain duration, shift changes, road conditions. The research method was carried out quantitatively. Optimization of coal transportation can be improved by improving delay parameters, improving communication between transportation operators, carrying out real time communication and data validation, expanding the Change Shift Area, fulfilling man power, making strip maps and road worthiness tests, making work plans, as well as procurement of gravel material and hauling road maintenance as well as All Weather Road conditions.

ОСОБЛИВОСТІ РОЗПОВСЮДЖЕННЯ ТЕХНОЛОГІЧНИХ СКРІПНИХ РОЗЧИНІВ В ПОРИСТІЙ СТРУКТУРІ ЩЕБЕНЕВОЇ ОСНОВИ АСФАЛЬТОБЕТОННОГО ПОКРИТТЯ ПРИ ІМПУЛЬСНОМУ ІН’ЄКЦІЙНОМУ ЗАКРІПЛЕННІ

The article is dedicated to the investigation of the peculiarities of spreading technological binding solutions within the porous structure of gravel base in asphalt concrete pavement through impulse injection fixation. The research utilizes a mathematical model based on Darcy's, Navier-Stokes, and Shvedov-Bingham equations to analyze the process of solution penetration into the material pores under the influence of impulse hydrodynamic pressures. The study is conducted on samples of various gravel bases, applying impulse solution injection. The obtained results provide a better understanding of the solution penetration process into the material pores and canals and examine the influence of various factors such as intensity, magnitude, and amplitude of periodic impulse hydrodynamic pressures, properties of technological binding solution, and fractionation of the gravel material. They also serve as a basis for optimizing the technology of asphalt concrete pavement construction on fixed gravel base, which can enhance the quality and durability of the road structure. The obtained results and utilized mathematical models can be beneficial not only for the road construction industry but also for other fields that utilize porous materials with binding solutions, such as technologies for improving the load-bearing capacity of foundation soil bases, landslide mitigation, and other similar cases.

An investigation of the efficacy of nanoemulsions as alternative treatment for a marginal quality pavement material

Stabilisation of road materials that do not meet specified requirements is a common practice in road construction. Cement and lime are among the most commonly used products for stabilisation. However, these products pose challenges in particular conditions, including rigidity and proneness to cracking, incompatibility with certain materials types and susceptibility to particular environmental conditions. In this regard, alternatives have been considered and nanotechnology-based materials have emerged as a viable option. For this study, the efficacy of Nano-Modified Emulsion (NME) for stabilisation of gravel material was investigated. The gravel material, stabilised with up to 1.5% NME was evaluated in the laboratory for mechanical strength characteristics and resistance to moisture damage. Results obtained for Static Triaxial Tests (STT) show that the NME improves the cohesion of the material by up to 54% but has no significant effect on the friction angle. Significant improvements are also noted in the results for California Bearing Ratio (CBR), Unconfined Compression Strength (UCS) and Indirect Tensile Strength (ITS) tests. The results also show that NME stabilisation improves the gravel material's resistance to moisture damage. Further investigations are recommended for repeated load triaxial tests, field trials, environmental risks and life cycle costs.

Egg-laying habitat selection of the invasive slug Krynickillus melanocephalus Kaleniczenko, 1851 (Gastropoda: Eupulmonata: Agriolimacidae)

Invasive slugs cause damage to biodiversity as well as to horticultural and agricultural crops. To develop methods to mitigate problems with recently emerging invasive species, basic ecological knowledge about them in their new environment is crucial. We investigated the egg-laying substrate preference of Krynickillus melanocephalus in a laboratory experiment in which the slugs could choose between four different substrates. Slugs were mainly observed in contact with birch leaf compost, and less so with gravel, potting soil and sphagnum moss. Almost 90% of the eggs were found buried in birch leaves, although eggs were found also in the other substrates. In addition, we tested the winter survival of the eggs by examining their susceptibility to low temperatures. Eggs subjected to freezing temperatures did not survive, and at 8 °C, 60–70% of the eggs hatched after three months (640 degree days). In areas where K. melanocephalus is present, transporting any soil, gravel or compost material could potentially contribute to spreading the species. Particularly, leaf composts may warrant attention in this areas.

Study on the performance of gravel stabilization by red mud-based cementitious materials

In this paper, red mud and slag were used as the main cementitious materials, and desulfurization gypsum and exciter materials were mixed to prepare red mud-based cementitious materials with excellent performance. The mechanical properties of red mud-based cementitious material stabilized gravel material were investigated by carrying out the compaction test, unconfined compressive strength test, splitting strength test and fatigue performance test. The test results show that with the increase in the dose of cementitious material, the hydration is more significant, generating more hydrated calcium silicate (C-S-H) gel, which in turn makes the unconfined compressive strength and splitting strength increase to a certain extent. Adding exciter and desulfurization gypsum in the appropriate amount is conducive to improving the hydration of red mud, improving the structural compactness, and improving the mechanical properties, volumetric stability and seepage resistance of the cementitious material.

Shear Resistance of Gravel Materials for Structural Layers of Road Clothes

Statement of the problem. The normative method for calculating the pavement of a road with low traffic intensity is based on two strength criteria which include checking the thickness of the pavement according to the general modulus of deformation and accumulated residual deformation of the surface of the coa-ting. Both calculation criteria assume the use of linear dependencies linking the precipitation with the pressure. It is known that the linear dependence of the precipitation on the pressure is possible only when the load does not exceed the first critical load of N. M. Gersevanov, at which a limiting state occurs at the most dangerous point of the soil mass according to the Mohr-Coulomb criterion. Thus, the necessity of calculating the pavement by shear resistance has been established. This implies the relevance of the work aimed at determining the adhesion and the angle of internal friction for materials and industrial waste that are not controlled by the regulatory documents of the Russian Federation. Results. The parameters of the limiting Coulomb straight line (coupling and angle of internal friction) of the gravel mix compacted to the requirements for the structural layers of road paving were determined. In solving this problem, the justification for the application of triaxial tests according to the consolidated untrained (CN) test scheme was carried out. The method of ramming a cylindrical sample in a small device of standard sealing equipped with two extension nozzles has been developed. The statistical processing of the test results was carried out and the calculated values of the adhesion and the angle of internal friction of the gravel mixture were established at a humidity of 0.72 of the moisture content of the loamy soil binding crushed stone at the yield boundary. Conclusions. The results make it possible to more reasonably calculate the thickness of the structural layer of a dirt-gravel mix of lower-type road clothes for roads with a low traffic intensity. The results of the work were implemented by designing lower-type road clothes for pilot construction in the conditions of the II, III and IV road-climatic zones of the Omsk region.

A Practical Group Symbol and Group Name Approach (PSNA) according to EN ISO 14688-2:2018

Classification systems are crucial to the description and classification of soils, helping to facilitate soil identification, as well as the understanding, and interpretation of soil materials worldwide. In this study, EN ISO 14688-2:2018 and ASTM D2487-17e1 were employed to develop a practical soil identification approach called Practical Group Symbol and Group Name Approach (PSNA). The method presented herein is not a classification system or a standard but is rather an approach that makes EN ISO 14688-2:2018 usable in practice and enables soil particle identification in detail. The use of this practical method can eliminate any ambiguity in communicating soil characteristics. Practical flow charts were prepared for defining group names and symbols of soil particles. The method enables the classification of gravel, sand, silt, clay, and organic material. A user-friendly macro was also developed in Microsoft Excel, utilizing the integrated programming language Visual Basic for Applications (VBA) to facilitate the implementation of this approach. In the present study, an Excel-based triangular diagram was developed. In addition to the triangular diagram, two charts were considered. From these contributions, the group symbol and group name of soil mixtures can be easily and practically defined.

Alternative uses for crushed stone products generated to meet the raw material needs of asphalt production in Hungary

In Hungary, quarries that produce stone products for wearing courses of asphalt pavements also produce a significant amount of 0/4, 0/8 and 4/8 mm fractions. Because of Hungary’s pavement design and asphalt production practices, these fractions do not have a suitable market and can thus be sold on alternative markets. Purpose. To demonstrate the feasibility of using crushed fractions of 0/4 and 0/8 mm in the protection and base layers of asphalt pavements instead of sandy gravel with 0/22 mm fraction. Methodology. The CBR method was applied to evaluate the comparability of characteristics such as particle size distribution and load-bearing capacity. The combination of the Proctor and CBR tests allowed someone to compare the expected technological characteristics of the dominant and alternative aggregate types, such as their sensitivity to water and load-bearing capacity. Findings. The results demonstrated that the performance characteristics of conventionally used sandy gravel with a size of 0/22 mm can be achieved and exceeded by crushed material with much smaller maximum grain sizes – i.e., 0/4 and 0/8 mm. Originality. The paper presents an original study that contradicts the industry’s actual decline of crushed stone (0/4 and 0/8 mm fractions) for asphalt pavement protection layers. The potential effectiveness and functionality of the proposed coating are demonstrated through convincing tests, and thus new data and insights are introduced into the Hungarian construction industry’s practice. Practical value. The test results greatly helped in achieving the high demands of the private industrial project by proposing an alternative variant of crushed stone of 0/8 mm fraction rather than the originally planned dominant sand and gravel material. The asphalt paving experience on this site clearly demonstrated the viability of the alternative aggregate option for Hungarian roads.