Cyclic Plate Load Tests Research Articles

Performance evaluation of marginal materials in geosynthetic reinforced base layers

The high-altitude regions are prone to natural disasters such as landslides, and tunnelling that generate substantial amounts of debris. Utilising these waste (marginal) materials in the pavement sector offers a viable solution. This study aims to stabilise tunnel muck, landslide debris, and Reclaimed Asphalt Pavement using geosynthetics (geogrid, geocell, double geogrid, and geogrid + geocell) for the base course. Cyclic Plate Load tests were performed on pavement prototypes built with available marginal materials and conventional GSB as the base/subbase course, with Black cotton and silty soil subgrades. The results indicated that geosynthetic reinforcement significantly improved the performance of marginal materials by lowering permanent deformation and increasing design life. The pavement prototypes reinforced with double geogrid and geogrid + geocell indicated rutting performance equivalent to conventional GSB for specific combinations. Additionally, incorporating geosynthetics in pavement layers increased the structural strength of the base layers by a layer coefficient ratio factor ranging from 1.1 to 2.5.

Performance evaluation of recycled concrete aggregates with geosynthetics as an alternative subbase course material in pavement construction

This study investigates the feasibility of using recycled concrete aggregates (RCA) as subbase materials in roads through laboratory experiments. Various physical tests were conducted on the soil subgrade and RCA subbase, followed by cyclic plate load tests to assess the impact of geosynthetic reinforcement on the bearing capacity of RCA materials. The ultimate bearing capacities of different RCA configurations ranged from 186 to 480 kPa, similar to previous studies on natural and recycled aggregates. The geocell-reinforced section exhibited excellent performance, with a measured ultimate bearing capacity of 480 kPa. The Geocell-Geogrid and Geocell-Geotextile sections showed the highest bearing capacity ratios at 2.58 each, indicating superior performance. Reinforced RCA infills demonstrated improved settlement values under repeated loading, with the geocell-geogrid section effectively reducing permanent settlement. The study concludes that RCA can be a substitute for natural aggregates in road subbase materials, mitigating the environmental impact of construction and demolition waste.

Performance evaluation of geosynthetic reinforced marginal material as base layer over weak subgrade

ABSTRACT The availability of quality materials for construction has been an issue in some regions. This scarcity obliged using marginal materials reinforced with geosynthetic materials as one of the quests for sustainability in the pavement industry. In this study, an attempt was made to stabilize the marginal materials by incorporating geosynthetics. The different geosynthetics used in the study are geogrid, geocell, double geogrid, and geocell + geogrid. A series of unreinforced (UR) and geosynthetic reinforced (GR) pavement prototypes were constructed in the laboratory with landslide debris as base material underlain by black cotton soil subgrade. Large-scale cyclic plate load (CPL) tests were performed on test prototypes constructed in the laboratory under cyclic loading following the trapezoidal loading pattern with 0.77 Hz frequency. The efficacy of geosynthetic reinforcement was quantified concerning permanent deformation (PD), resilient deformation (RD), Rut depth reduction (RDR), Traffic improvement ratio (TIR), and reduction in vertical stresses transmitted to the subgrade and reduction in base layer thickness. The test results indicate that the GR significantly reduced the rut depth and improved the traffic capacity. In addition, over all types of GRs, the combination of geogrid and geocell outperformed in terms of permanent deformation and rut depth reduction.

Laboratory Evaluation of Marginal and Industrial Waste Material in Geocell-Reinforced Pavements under Cyclic Loading

Abstract The availability of quality materials for the construction of pavements has been a problem in some regions. This scarcity enforced geosynthetic materials as one of the quests for su1stainability in the pavement industry. This study attempted to stabilize marginal (tunnel muck, reclaimed asphalt pavement material) and industrial waste (zinc slag) materials by employing high density polyethylene geocell to appraise the effectiveness of geosynthetic reinforcement in enhancing the characteristics of pavement materials and mitigating their rutting. The cyclic plate load tests are performed on marginal and industrial waste material with geocell-reinforced and unreinforced base layers over black cotton soil as the subgrade. The tests were conducted following the trapezoidal loading pattern with a 0.77-Hz frequency. The geocell-reinforced pavement performance was evaluated for resilient deformation, accumulated permanent deformation, rut depth reduction, traffic benefit ratio, and base layer thickness reduction. The mechanistic empirical pavement design guide (MEPDG) permanent deformation performance (PDP) model framework was used to predict the accumulated permanent deformation in unbound granular layers and to differentiate the rutting performance in geocell-reinforced and unreinforced sections. This study determined the material constants of the MEPDG PDP model for marginal and industrial waste materials used in the pavement section for quantifying the reduction in base layer thickness.

Evaluation of Granular Fill Layer Underlain by Soft Clay Soil Using Large Scale Cyclic Plate Loading Tests

Evaluation of Granular Fill Layer Underlain by Soft Clay Soil Using Large Scale Cyclic Plate Loading Tests

Amelioration of flexible pavement subbases using fly ash and natural fibres

The use of fly ash as a stabilizing element has already been demonstrated to be successful. Moreover, the CBR values of fly ash do not meet IRC criteria. This study intends to analyze the addition of coir fibre, a natural and environmentally sustainable resource, as a reinforcing material. Fly ash and coconut coir are waste materials that can be locally sourced, making them cost-effective and environmentally friendly materials. The article discusses the benefits of fly ash and coconut coir in flexible pavement subbases, highlighting their potential as a sustainable solution for road construction and maintenance. The laboratory experiments conducted on fly ash subbases reinforced with various percentages of coconut coir ranging from 0.1, 0.2, and 0.3 prove that the addition of natural fibres can enhance the subbase's strength properties, with a maximum improvement observed at a 0.2% reinforcement level. Further, the cyclic plate load tests conducted on the treated fly ash subbase at optimum conditions provide valuable insights into the subbase's performance under repeated loading conditions. The results suggest that the natural fibres performed satisfactorily in improving the subbase's load-carrying capacity and reducing rebound deformations, indicating that this approach can be a viable alternative to conventional pavement subbase materials.

Geocell-reinforced bed under static and cyclic loads: Soil density and grain size effects

This paper reports on a series of static and cyclic plate loading tests performed on a weak unreinforced sand bed in a test pit. The weak sand was covered by a 160 mm thick layer comprised of one of three compacted soil types which was either unreinforced or geocell-reinforced. The purpose was to investigate the effects of soil density and grain size as filler materials for the covering layer. The three covering soils were granular with average particle sizes of 2.2 (Soil 1), 6.14 (Soil 2), and 8.47 (Soil 3) mm. Under static loading, the bearing pressure increased on average 23% when the average grain size of the upper, unreinforced, soil layer changed from 2.20 mm to 8.47 mm. The improvement in bearing pressure was about 37% due to the use of a soil-filled geocell but, unlike the unreinforced situation, employing larger soil grains to fill the geocell pockets didn't show significant further improvement. For cyclic loading tests, the maximum settlement reduction by employing a geocell layer was about 50% for Soil 1. Whether loaded statically or cyclically, increasing soil density likely would be more efficient for improving geocell performance than employing a soil having larger particle sizes.

Uses of Usumacinta River sediments as a sustainable resource for unpaved roads: An experimental study on a full-scale pilot unit

PurposeTransportation is a key factor for economic growth and poverty reduction because it improves access to services and opportunities for rural communities. Unpaved roads, however, still represent 80% of the global road network. The state of Tabasco, Mexico, is not an exception. Materials and methodsGeotechnical identifications of raw and lime-treated sediments are performed. A methodology is developed to reproduce a soil-model close to the raw sediment's properties. The reconstituted soil-model is used for full-scale testing including CBR indexes determination, cyclic vertical plate testing and horizontal traffic loads tests. ResultsThe rutting generated from the cyclic plate and traffic load tests, on both the untreated and the lime-treated soil-model, are compared. The lime treatment appears to improve the properties of both the soil-model and the sediments. ConclusionsThe findings give promising perspectives regarding the use of Usumacinta River sediments for the construction of unpaved roads.

Behaviour of a weakly bonded residual soil subjected to monotonic and cyclic loading

Residual soils are found all around the world. Their behaviour is different from ‘classic’ soils due to the structure resulting from the geological formation processes, which can eventually undergo degradation under static and cyclic loads, with a decrease in both stiffness and strength. In this context, the aim of the present study was to evaluate the behaviour of weakly bonded residual soil in the face of loading and unloading cycles using field plate load tests. Preliminary field and laboratory tests were carried out to characterise the residual soil at the experimental site. Monotonic and cyclic plate load tests – with circular and square plates – were performed under three different load amplitudes. The results showed no shape effect of the loaded area for both monotonic and cyclic loading, considering the same loading pattern. Also, there is a threshold load, which indicates a yielding point and a change in soil behaviour and can be estimated from simple laboratory tests. Below this load, the residual soil presented a rigid behaviour even when subjected to cyclic loads.

Quantifying the Benefits of Geosynthetics Reinforcement in Flexible Pavement Design Using Cyclic Plate Load Testing

Development of pavement design over the past decades has focused on moving from empirical design equations to more powerful and adaptive design schemes. The AASHTO mechanistic–empirical pavement design guide (MEPDG) has been developed to model pavement structure and predict its service life more accurately. Although MEPDG has been widely implemented to design conventional pavement, it is not yet capable of predicting the service life of pavement reinforced with geosynthetics. Given the above concerns, seven full-scale test sections that were constructed at Louisiana Transportation Research Center-Pavement Research Facility (LTRC-PRF) were devoted to a structural experiment to investigate the performance of geosynthetic reinforced pavements. The benefits of using geosynthetics to enhance the performance of pavements constructed over soft subgrades was evaluated using cyclic plate load testing. Cyclic load at a frequency of 0.77 Hz was applied through a 305 mm diameter steel plate. The test results clearly show the benefits of geosynthetics in significantly reducing pavement rutting. The test section with double geosynthetic layers performed better than the other six sections studied. After eliminating the effect of variations in construction, the benefits of geosynthetic reinforcement are quantified within the context of the AASHTOWare Pavement ME Design Guide. The developed design procedure is capable of quantifying the contribution of geosynthetics in pavements to base reinforcement as well as subgrade stabilization. A design methodology is proposed that falls within the context of MEPDG.

Experimental evaluation of wicking geotextile-stabilized aggregate bases over subgrade under rainfall simulation and cyclic loading

Wicking geotextile has been increasingly utilized in field projects to mitigate water-related roadway problems. The previous studies showed that the wicking geotextile could provide mechanical stabilization, serve as capillary barrier, and enhance lateral drainage. The wicking geotextile differentiates itself from non-wicking geotextiles by providing capillary or wicking drainage in unsaturated conditions, whereas non-wicking geotextiles only provide gravitational drainage under saturated or near-saturated conditions. Although the previous studies have demonstrated the benefits of soil water content reduction by the wicking drainage, it is not well understood how the wicking geotextile stabilization improves overall performance of aggregate bases over subgrade under traffic or cyclic loading. This paper presents an experimental study where large-scale cyclic plate loading tests were conducted under different conditions: (1) non-stabilized base, (2) non-wicking geotextile-stabilized base, and (3) wicking geotextile-stabilized base, over soft and moderate subgrades. Rainfall simulation was carried out for each test section. After each rainfall simulation, a drainage period was designed to allow water to drain from the section. The amounts of water applied and exiting from the test section were recorded and are compared. Cyclic loading was applied after each drainage period. The test results show that the combined hydraulic and mechanical stabilization effect by the wicking geotextile reduced the permanent deformation of the aggregate base over the subgrade as compared with the non-stabilized and non-wicking geotextile-stabilized sections.

Dynamic Analysis of Machine Foundation with and without Geosynthetic Reinforced Soil Beds

Most of the machine foundations are located in the regions with poorly graded soil including loose sand. Hence, the experimental studies are undertaken to evaluate the dynamic parameters of geosynthetics using cyclic PLT. This paper presents the results of the 10 m2 area of the model cyclic plate load test conducted on geosynthetics reinforced soil beds with similar density, supporting square footing, the results of cyclic PLT from the laboratory-model tests on square footings resting on a sand bed. The various intensity of cyclic load (loading-unloading) applying on the footing and then the elastic recovery of the footing alike to each intensity of loading obtains during the tests to determine the coefficient of elastic uniform compression (Cu) of sand. Results showes that the provision of geosynthetics like geogrid and jute the value of Cu decreases due to elastic recovery increases as compared to unreinforced soil bed, by 06% to 94% and natural frequency 03% to 76% . Introduction of planer geogrid at the base of the geosynthetic matress not only enhance the load carrying capacity but also increasing the elastic recovery to making them more elastic and prevents footing to failure due to vibration. In addition to the experiments also analyses various dynamic parameters of the machine foundation using cyclic PLT on the geosynthetics

WITHDRAWN: Reinforced sand bed bearing capacity prediction in presence of cyclic & monotonic loading

Technique of reinforcing soil beds it was very common & old method for enhancing load keeping capability of soil & decreasing settlement. Whatever, method has been not adopted totally, as in past there has been rare researches available including this technique of design & analysis. So soil reinforcement communication should analyse properly. Possibility of technique for assuming bearing capacity enhance underground of reinforced sandy has examined through user utilizing test executed in different test situations. In the present investigation, total four different types of reinforcing materials have been used. Four model circular footings of various internal diameters are been used for investigating affect of annular ratio on bearing capability of the sand bed along different reinforcing conditions. Model plate load test have been performed under monotonic & cyclic loading in three series which are mentioned for Monotonic plate load tests on a ring footing resting on sand beds reinforced along Geogrid-Netlon-CE121 as reinforcing material- Fifteen numbers, Cyclic plate-load tests along Geogrid-Netlon-CE121 as reinforcing material - Fifteen numbers, Monotonic plate-load tests along Geo-jute as reinforcing material - Nine numbers, Cyclic plate-load tests along Geo-jute as reinforcing material - Nine numbers.

Evaluation of Reclaimed Hydrated Fly Ash as an Aggregate for Sustainable Roadway Base Material

This paper summarizes the findings from laboratory and field performance testing of reclaimed hydrated class C fly ash (HFA) stabilized with a triangular aperture geogrid. This phase of testing was performed on HFA laboratory specimens and field test sections. The laboratory test results provided estimates for design input values, while the field testing assessed performance characteristics including the as-constructed modulus of the subgrade reaction, the in situ resilient modulus, and permanent deformation. For the laboratory portion, all results were derived from tests conducted on specimens immediately after sample preparation and after a 7-day cure. The compressive strength of reclaimed hydrated class C fly ash increases with curing. The strength of the HFA material can be further increased when mixed with a chemical stabilizer. For this project, chemical stabilization with lime was not viable because the lime supplier was too far from both HFA source and project site. Based on cyclic plate load tests, the in situ resilient modulus of the HFA and geogrid-stabilized HFA layers were determined on site. This paper reports the findings from the laboratory and field plate load test and highlights the potential use of geogrids in the stabilization of HFA.

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.

Evaluating and improving the construction and demolition waste technical properties to use in road construction

Abstract The volume of Construction and Demolition Wastes is dramatically increasing around the world, mainly in urban areas, giving rise to environmental damage. In Tehran, producing 50,000 tons of the construction and demolition wastes (CDW) has made the lack of suitable sites for the disposal. This study aims were to evaluate the physical and mechanical properties of the CDW to possibly use in road construction, specifically as sub-base materials. To do so, after crushing the selected material from the disposal, a few important physical tests, including soil grading, Atterberg limits, modified compaction, California Bearing Ratio, and direct shear test were carried out to assess the obtained values with those exerted by standards in road construction. Furthermore, a series of cyclic plate load tests have been carried out to evaluate the effectiveness of geocell reinforcement on the bearing capacity of CDW materials. The results showed that the physical and mechanical properties of the studied CDW materials agreed with the majority of the standard criteria to be used as sub-base materials in road construction. The results of plate load tests revealed that cyclic bearing capacity of CDW backfills was 20–40% lower than that of standard material. However, geocell reinforcement could not only improve the CDW cyclic response approaching to natural aggregate (NA) response, but also boost bearing capacity ratio well above than one for all CDW materials.

Performance of Geosynthetics Reinforced Subgrade Subjected to Repeated Vehicle Loads: Experimental and Numerical Studies

Use of the geosynthetics to strengthen the soil is one of the highly desirable techniques under static and dynamic loads. The present study describes the experimental and numerical studies performed on the geosynthetic reinforced subgrade subjected to repeated vehicle loads. The cyclic plate load tests were conducted on the sand subgrade reinforced with planar and 3D geosynthetic reinforcements. The vehicle load was simulated by applying a repeated load of magnitude 275 kPa with 1Hz frequency on the reinforced subgrade. Results of the experimental investigations revealed that the performance of the subgrade soil improved significantly in the presence of reinforcements. The estimated parameters illustrated the three-fold reduction in settlement of the subgrade in the presence of reinforcement. Further, the heaving of the subgrade soil was found completely arrested with the use of geosynthetic reinforcement. The three-dimensional geocell reinforcement performed effectively as compared to planar geogrids under dynamic load. The measured pressure values at different depth demonstrated a significant reduction in the pressure in the presence of reinforcements. Besides, numerical simulations were performed using PLAXIS2D to understand pressure and settlement distribution patterns in the reinforced subgrade. In overall, a good agreement was observed between numerical and experimental results.

Influence of Shape of Footing on Coefficient of Elastic Uniform Compression of Foundation Soils

Coefficient of elastic uniform compression (Cu) of soil, used in the determination of soil spring stiffness for design of foundations of industrial structures and structures subjected to dynamic loads, is generally determined from cyclic plate load tests. The values of Cu determined with respect to test plate size are corrected for actual foundation size based on Barkan’s equation. However, no established shape factor is available from the literature for arriving at the value of Cu of circular footing from Cu determined from plate load test results on square test plates. Hence, in the present work, the effect of shape of loading plate on Cu is studied in cohesionless and cohesive soils through small-scale cyclic load tests conducted in the laboratory using square and circular loading plates of same size. The results of study revealed that the value of coefficient of elastic uniform compression (Cu) of square test plate is about 0.85 and 1.2 times of Cu of circular plate in fine sand and cohesive soils, respectively.

Cyclic plate testing of geosynthetic-reinforced airfield pavements

Numerous cyclic plate load tests have been performed over the past several years to investigate the potential performance benefits of including geosynthetics in paved and unpaved applications. A majority of these studies have focused on relatively thin pavement structures subjected to highway loads. Airfield pavements can be substantially thicker and include multiple aggregate layers, and data are needed to quantify geosynthetic contributions under high contact pressures (CPs). Eleven representative airfield pavement structures (four unreinforced sections, four containing geosynthetics at the subbase−subgrade interface and three containing geosynthetics at the base−subbase interface) were constructed in a laboratory containment facility and subjected to cyclic loading under 1750 kPa simulated aircraft CP. Permanent surface deformation and vertical pressure response data were collected to determine relative improvement when compared with an unreinforced pavement structure and to evaluate the influence of geosynthetics. Some geosynthetics increased the number of cycles to failure, and it was found that some level of permanent deformation (e.g. 25 mm) may be required to engage reinforcing benefits when placement occurs at the subgrade−subbase interface. Changing subbase material from a California bearing ratio of 15–18 to 55 resulted in 1·5 orders of magnitude more cycles to 25 mm of permanent deformation than any of the geosynthetic-reinforced sections evaluated.

Response of pavement foundations incorporating both geocells and expanded polystyrene (EPS) geofoam

The suitability of geocell reinforcement in reducing rut depth, surface settlements and/or pavement cracks during service life of the pavements supported on expanded polystyrene (EPS) geofoam blocks is studied using a series of large-scale cyclic plate load tests plus a number of simplified numerical simulations. It was found that the improvement due to provision of geocell constantly increases as the load cycles increase. The rut depths at the pavement surface significantly decrease due to the increased lateral resistance provided by the geocell in the overlying soil layer, and this compensates the lower competency of the underlying EPS geofoam blocks. The efficiency of geocell reinforcement depends on the amplitude of applied pressure: increasing the amplitude of cyclic pressure increasingly exploits the benefits of the geocell reinforcement. During cyclic loading application, geocells can reduce settlement of the pavement surface by up to 41% compared to an unreinforced case – with even greater reduction as the load cycles increase. Employment of geocell reinforcement substantially decreases the rate of increase in the surface settlement during load repetitions. When very low density EPS geofoam (EPS 10) is used, even though accompanied with overlying reinforced soil of 600 mm thickness, the pavement is incapable of tolerating large cyclic pressures (e.g. 550 kPa). In comparison with the unreinforced case, the resilient modulus is increased by geocell reinforcement by 25%, 34% and 53% for overlying soil thicknesses of 600, 500 and 400 mm, respectively. The improvement due to geocell reinforcement was most pronounced when thinner soil layer was used. The verified three-dimensional numerical modelings assisted in further insight regarding the mechanisms involved. The improvement factors obtained in this study allow a designer to choose appropriate values for a geocell reinforced pavement foundation on EPS geofoam.