Cyclic Plate Load Testing of Geosynthetic-Reinforced Unbound Aggregate Roads

2005 ◽  
Vol 1936 (1) ◽  
pp. 60-69 ◽  
Author(s):  
Jeb S. Tingle ◽  
Sarah R. Jersey
Keyword(s):  
Permanent Deformation ◽  
Construction Materials ◽  
Laboratory Research ◽  
Load Testing ◽  
Test Analysis ◽  
Additional Information ◽  
Road Section ◽  
Standard Construction ◽  
Load Tests ◽  
Mechanistic Response

A laboratory research program designed to investigate geotextile and geogrid reinforcement of the aggregate layer in unbound pavement sections was performed by the U.S. Army Engineer Research and Development Center. The investigation's objective was to evaluate the performance of geosynthetic-reinforced aggregate road sections over a very soft subgrade. Standard construction materials were used to construct six aggregate road sections in a large steel box. Each instrumented road section was subjected to cyclic plate load tests to evaluate the performance of the model pavement sections under simulated truck traffic. The mechanistic response and permanent deformation of each instrumented pavement section were monitored periodically during each test. Analysis of the experiment data indicated that the geosynthetics improved the performance of the reinforced pavement sections compared with the unreinforced section in terms of improved load distribution and reduced permanent deformation or rutting. Additional information regarding the reinforcement mechanisms is summarized.

Investigation of Grouted Coupler Connection Details for Accelerated Bridge Construction

2021 ◽  
pp. 036119812199939
Author(s):  
Brent Phares ◽  
Yoon-Si Lee ◽  
Travis K. Hosteng ◽  
Jim Nelson
Keyword(s):  
Crack Width ◽  
High Performance ◽  
Static Load ◽  
High Performance Concrete ◽  
Precast Concrete ◽  
Chloride Penetration ◽  
Load Testing ◽  
Test And Evaluation ◽  
Load Tests ◽  
Precast Elements

This paper presents a laboratory investigation on the performance of grouted rebar couplers with the connection details similar to those utilized on the precast concrete elements of the Keg Creek Bridge on US 6 in Iowa. The testing program consisted of a series of static load tests, a fatigue test, and evaluation of the chloride penetration resistance of laboratory specimens. The goal of this testing was to evaluate the ability of the grouted rebar couplers to develop flexural capacity at the joint between the precast elements as well as the durability of the connection. For structural load testing, seven full-scale specimens, each with #14 epoxy-coated rebars spliced by epoxy-coated grouted couplers, were fabricated and tested in three different loading cases: four-point bending, axial tension plus bending, and a cyclic test of the system in bending. The static load testing demonstrated that the applied axial load had a minimal effect on the formation of cracks and overall performance of the connection. When ultra-high performance concrete was used as a bedding grout, the initiation of crack was slightly delayed but no considerable improvement was observed in the magnitude of the crack width during loading or the crack closure on unloading. The results of the seventh specimen, tested in fatigue to 1 million cycles, showed little global displacement and crack width throughout the test, neither of which expanded measurably. No evidence of moisture or chloride penetration was detected at the grouted joint during the 6-month monitoring.

Driven cast-in-situ pile capacity: insights from dynamic and static load testing

2021 ◽  
Author(s):  
Kevin N. Flynn ◽  
Bryan A. McCabe
Keyword(s):  
Dynamic Load ◽  
Shear Stresses ◽  
Load Testing ◽  
Pile Capacity ◽  
Compression Load ◽  
Shaft Resistance ◽  
Pile Installation ◽  
Cast Concrete ◽  
Load Tests

Driven cast-in-situ (DCIS) piles are classified as large displacement piles. However, the use of an oversized driving shoe introduces additional complexities influencing shaft resistance mobilisation, over and above those applicable to preformed displacement piles. Therefore, several design codes restrict the magnitude of shaft resistance in DCIS pile design. In this paper, a series of dynamic load tests was performed on the temporary steel driving tubes during DCIS pile installation at three UK sites. The instrumented piles were subsequently subjected to maintained compression load tests to failure. The mobilised shear stresses inferred from the dynamic tests during driving were two to five times smaller than those on the as-constructed piles during maintained load testing. This was attributed to soil loosening along the tube shaft arising from the oversized base shoe. Nevertheless, the radial stress reductions appear to be reversible by the freshly-cast concrete fluid pressures which provide lower-bound estimates of radial total stress inferred from the measured shear stresses during static loading. This recovery in shaft resistance is not recognised in some European design practices, resulting in conservative design lengths. Whilst the shaft resistance of DCIS piles was underpredicted by the dynamic load tests, reasonable estimates of base resistance were obtained.

Predicting the Ultimate Bearing Capacity of Single Piles Based on CPTU

2011 ◽  
Vol 243-249 ◽  
pp. 4402-4407
Author(s):  
Yong Hong Miao ◽  
Guo Jun Cai ◽  
Song Yu Liu
Keyword(s):  
Load Test ◽  
Load Testing ◽  
Pile Capacity ◽  
Piezocone Penetration Test ◽  
Load Carrying ◽  
Load Tests ◽  
Pile Load Test ◽  
Single Piles ◽  
Pile Load Tests ◽  
Best Fit

Six methods to determine axial pile capacity directly based on piezocone penetration test (CPTU) data are presented and evaluated. Analyses and evaluation were conducted on three types piles that were failed during pile load testing. The CPT methods, as well as the CPTU methods, were used to estimate the load carrying capacities of the investigated piles (Qp ). Pile load test were used to determine the measured load carrying capacities (Qm). The pile capacities determined using the different methods were compared with the measured pile capacities obtained from the pile load tests. Two criteria were selected as bases of evaluation: the best fit line for Qp versus Qm and the arithmetic mean and standard deviation for the ratio Qp /Qm. Results of the analyses showed that the best methods for determining pile capacity are the CPTU methods.

Effects of Compaction Moisture Content on Permanent Deformation of Soils Subjected to Repeated Triaxial Load Tests

2019 ◽  
Vol 2673 (2) ◽  
pp. 466-476 ◽  
Author(s):  
Caroline Dias Amancio de Lima ◽  
Laura Maria Goretti da Motta ◽  
Francisco Thiago Sacramento Aragão
Keyword(s):  
Moisture Content ◽  
Permanent Deformation ◽  
Tropical Soils ◽  
Asphalt Pavements ◽  
Design Guide ◽  
Compaction Curve ◽  
Triaxial Loads ◽  
Load Tests ◽  
Deformation Tests ◽  
Elastic And Plastic Deformation

Water content is one of the key parameters that can cause variations in the elastic and plastic deformation of pavement layers. More specifically, both the compaction moisture and the post-compaction moisture should be carefully controlled. The objective of this study is to analyze the effects of compaction moisture on the accumulation of permanent deformation when unbound materials are subjected to repeated triaxial loads. The moisture contents were defined according to the compaction curve of each soil, being one above and one below the optimum moisture content which has been typically considered for the design of asphalt pavements in Brazil. The four soils evaluated in the study are commonly used in flexible pavements and have different classifications according to the Brazilian Miniature, Compacted, Tropical (MCT) methodology tailored to classify tropical soils. Specimens were subjected to permanent deformation tests and the results obtained show that the moisture content can significantly affect the mechanical behavior of soils. That effect is significant on both sides of the compaction curve, but the permanent deformation increases as the compaction moisture content increases on the wet side. This work is part of a broader and comprehensive research project in progress in Brazil to continuously update the current version of the Brazilian mechanistic-empirical pavement design guide. The proper understanding and characterization of the resistance to permanent deformation of unbound materials is a key part of that design guide.

scholarly journals Bi-Directional Static Load Tests of Pile Models

2020 ◽  
Vol 10 (16) ◽  
pp. 5492
Author(s):  
Michał Baca ◽  
Włodzimierz Brząkała ◽  
Jarosław Rybak
Keyword(s):  
Bearing Capacity ◽  
Static Load ◽  
Load Testing ◽  
Pile Capacity ◽  
Pile Shaft ◽  
Load Tests ◽  
S Curve ◽  
Definition Of ◽  
Standard Tests ◽  
Static Load Testing

This work examined a new method of bi-directional static load testing for piles, referencing the Osterberg test. Measurements were taken, on a laboratory scale, using six models of piles driven into a box filled with sand. This method allowed for separate measurements of pile base and pile shaft bearing capacities. Based on the results, the total pile bearing capacity and equivalent Q–s diagrams were estimated. The results obtained show that the structure of the equivalent curve according to Osterberg is a good approximation of the standard Q–s curve obtained from load tests, except for loads close to the limit of bearing capacity (those estimates are also complicated by the inapplicability and ambiguity of a definition of the notion of limit bearing capacity); the equivalent pile capacity in the Osterberg method represents, on average, about 80% of the capacity from standard tests.

scholarly journals Recent developments and perspectives on the treatment of industrial wastes by mineral carbonation — a review

2013 ◽  
Vol 3 (4) ◽  
Author(s):  
Marius Bodor ◽  
Rafael Santos ◽  
Tom Gerven ◽  
Maria Vlad
Keyword(s):  
Structural Integrity ◽  
Waste Treatment ◽  
Construction Materials ◽  
Industrial Sector ◽  
Industrial Wastes ◽  
Laboratory Research ◽  
Stable Form ◽  
Mineral Carbonation ◽  
Precipitated Calcium Carbonate ◽  
Carbonation Reaction

AbstractBesides producing a substantial portion of anthropogenic CO2 emissions, the industrial sector also generates significant quantities of solid residues. Mineral carbonation of alkaline wastes enables the combination of these two by-products, increasing the sustainability of industrial activities. On top of sequestering CO2 in geochemically stable form, mineral carbonation of waste materials also brings benefits such as stabilization of leaching, basicity and structural integrity, enabling further valorization of the residues, either via reduced waste treatment or landfilling costs, or via the production of marketable products. This paper reviews the current state-of-the-art of this technology and the latest developments in this field. Focus is given to the beneficial effects of mineral carbonation when applied to metallurgical slags, incineration ashes, mining tailings, asbestos containing materials, red mud, and oil shale processing residues. Efforts to intensify the carbonation reaction rate and improve the mineral conversion via process intensification routes, such as the application of ultrasound, hot-stage processing and integrated reactor technologies, are described. Valorization opportunities closest to making the transition from laboratory research to commercial reality, particularly in the form of shaped construction materials and precipitated calcium carbonate, are highlighted. Lastly, the context of mineral carbonation among the range of CCS options is discussed.

scholarly journals Olfaction in patients with Parkinson’s disease: a new threshold test analysis through turning points trajectories

2021 ◽  
Author(s):  
Maria Paola Cecchini ◽  
Elisa Mantovani ◽  
Angela Federico ◽  
Alice Zanini ◽  
Sarah Ottaviani ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Test Pattern ◽  
Turning Points ◽  
Motor Symptom ◽  
Olfactory Threshold ◽  
Test Analysis ◽  
Threshold Test ◽  
Additional Information ◽  
Olfactory Deficit

AbstractOlfactory deficit is a widely documented non-motor symptom in Parkinson’s disease (PD). Abnormal turning points trajectories through olfactory threshold testing have been recently reported in patients with olfactory dysfunction, who seem to adapt faster to olfactory stimuli, but data on PD patients are lacking. The aim of this study is to perform olfactory threshold test and explore the turning points trajectories in PD patients in comparison to normal controls. We recruited 59 PD patients without dementia, and no conditions that could influence evaluation of olfaction and cognition. Sixty healthy subjects served as controls. Patients and controls underwent a comprehensive olfactory evaluation with the Sniffin’ Sticks extended test assessing threshold, discrimination and identification and a full neuropsychological evaluation. Besides, threshold test data were analyzed examining all the turning points trajectories. PD patients showed a different olfactory threshold test pattern, i.e., faster olfactory adaptation, than controls with no effect of age. Normosmic PD patients showed different olfactory threshold test pattern, i.e., better threshold score, than normosmic controls. Visuospatial dysfunction was the only factor that significantly influenced this pattern. Olfactory threshold trajectories suggested a possible adaptation phenomenon in PD patients. Our data offered some new insights on normosmic PD patients, which appear to be a subset with a specific psychophysical profile. The analysis of the turning points trajectories, through an olfactory threshold test, could offer additional information on olfactory function in PD patients. Future larger studies should confirm these preliminary findings.

scholarly journals Intermittent cyclic load testing of polymer railway sleepers

2021 ◽  
pp. 095440972110454
Author(s):  
Aran van Belkom ◽  
Matthias Pittrich ◽  
Vit Lojda
Keyword(s):  
Laboratory Tests ◽  
Cyclic Load ◽  
Strain Curve ◽  
Elastic Behaviour ◽  
Test Time ◽  
Loading Frequency ◽  
Load Testing ◽  
Heat Accumulation ◽  
Strength Assessment ◽  
Load Tests

Before a new type of railway sleeper can be used in track, standardised laboratory tests must be carried out to determine its suitability. In addition to static load tests, assessments usually include cyclic load tests consisting of millions of load cycles, representing passing trains during the sleeper’s service life. In these laboratory tests, the loading cycles are applied continuously without resting periods to condense the test time. Traditional sleeper materials (timber, concrete) possess elastic properties for which such testing is appropriate. However, polymer sleepers exhibit viscoelastic properties, such as creep, a loading rate-dependent stiffness and heating due to non-linearity of the stress-strain curve. Subjecting polymer sleepers to continuous cyclic load tests with a load frequency reflecting permissible track speed can cause the sleeper to heat up. Intermittent testing with pauses between numbers of load cycles is proposed in this paper as a possible solution. The aim is to propose a laboratory loading procedure that adopts a traffic-resembling load of a railway line, considering an effective compromise between polymer visco-elastic behaviour and time consumption of the laboratory tests. The loading frequency is kept at the desired strain rate for track evaluation, giving a representative sleeper stiffness and strength assessment. Exemplary tests with varying test arrangements and loading procedures were performed to quantify the effects of intermittent loading in comparison with continuous loading. The proposed method eliminated most of the test-induced creep and heat accumulation, resulting in a more representative stiffness and strength assessment, which justifies the proposed intermittent testing for polymer sleepers. The proposed intermittent procedure is an optional test regime in ISO 12856-2 for polymer sleeper testing.

scholarly journals The Effects of Yoga Practice on Practitioners' Environmental Behaviours & Sustainability

2021 ◽  
Vol 10 (3) ◽  
pp. 76
Author(s):  
Aglaia Zafeiroudi ◽  
Mathildi Pipinia ◽  
Georgia Yfantidou ◽  
Sotiriοs Georgomanos
Keyword(s):  
Codes Of Conduct ◽  
Leisure Activity ◽  
Yoga Practice ◽  
Individual Values ◽  
Test Analysis ◽  
Environmental Behaviour ◽  
Additional Information ◽  
Responsible Behaviour ◽  
The Individual ◽  
Environmental Behaviours

Yoga philosophy includes ethical codes of conduct, guidelines, meditation and other practices that respect the Earth, its natural resources, humans and other living beings. The purpose of the present study was to investigate the effects of yoga practice on practitioners' environmental behaviours and sustainability. A total of 195 adults (66 men and 129 women) from two cities in Greece participated in this study. The participants completed the General Environmental Responsible Behaviour scale (Zafeiroudi & Hatzigeorgiadis, 2013) and provided additional information about their personal lifestyles, leisure activity preferences and frequency of participation in outdoor activities. Independent sample T-test analysis was used to investigate differences between practitioners' demographics and the General Environmental Responsible Behaviour scale as the dependent variable. The results indicated statistically significant differences in environmental behaviour scores among practitioners in different yoga demographics. On the basis of yoga philosophy, the study findings suggested that participation in yoga practices strengthens beliefs, behaviours and awareness regarding the environment. The individual values taught by the philosophy of yoga also foster friendlier attitudes and behaviours towards the environment. Moreover, the findings indicated that yoga practice might be an effective supplement and tool to promote green sustainable programs currently run by environmental and social organizations.

A Review of the Utilisation of Recycled Waste Material as an Alternative Modifier in Asphalt Mixtures

2020 ◽  
Vol 6 ◽  
pp. 42-60
Author(s):  
Abdalrhman Abrahim Milad ◽  
Ahmed Suliman B. Ali ◽  
Nur Izzi Md Yusoff
Keyword(s):  
Mechanical Performance ◽  
Permanent Deformation ◽  
Steel Slag ◽  
Asphalt Mixture ◽  
Construction Materials ◽  
Crumb Rubber ◽  
Asphalt Mixtures ◽  
Waste Material ◽  
Waste Materials ◽  
The Road

The possibility of using waste materials in road construction is of great interest as their utilisation may contribute to reducing the problems of hazard and pollution and conserve natural resources. Thus, there is an urgent need to find a sustainable method for using waste materials as a substitute in the standard asphalt binders. There are several concerns about the physical and chemical properties and mechanical performance of asphalt pavements incorporated with waste material in the effort to reduce permanent deformation of the road surface. This review article presents a brief discussion of the asphalt mixtures modified with waste material, and the recycled materials used as a modifier in the asphalt mixture. The present paper summarises the use of crumb rubber, crushed concrete, steel slag, glass fibre and plastic waste in asphalt mixtures. The use of waste materials as a modifier in asphalt mixture resulted in improved asphalt pavement performance. Results advocate that rubberised asphalt mixture with desired properties can be designed as an additive with a friendly environmental approach in construction materials. The researches that adopted the influence of usage, recycle waste material to improve the performance of the asphalt of the road are still limited compared to other construction fields. Doi: 10.28991/cej-2020-SP(EMCE)-05 Full Text: PDF

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